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| author | Keiron Liddle <keiron@apache.org> | 2002-12-02 10:19:43 +0000 |
|---|---|---|
| committer | Keiron Liddle <keiron@apache.org> | 2002-12-02 10:19:43 +0000 |
| commit | eb328349433beebe9441d6b89c7a554e11f0f198 (patch) | |
| tree | 6c10218fa7641efcd85e45c67f3852b71fb6377d /src/documentation/content/xdocs/design/alt.design | |
| parent | a369435ba96c4467b05f9776f49c00238822ac30 (diff) | |
| download | xmlgraphics-fop-eb328349433beebe9441d6b89c7a554e11f0f198.tar.gz xmlgraphics-fop-eb328349433beebe9441d6b89c7a554e11f0f198.zip | |
initial conversion of alt.design docs
git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@195701 13f79535-47bb-0310-9956-ffa450edef68
Diffstat (limited to 'src/documentation/content/xdocs/design/alt.design')
21 files changed, 3589 insertions, 0 deletions
diff --git a/src/documentation/content/xdocs/design/alt.design/AbsolutePosition.png.xml b/src/documentation/content/xdocs/design/alt.design/AbsolutePosition.png.xml new file mode 100644 index 000000000..46a6999a3 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/AbsolutePosition.png.xml @@ -0,0 +1,21 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>AbsolutePosition diagram</title> + <authors> + <person id="pbw" name="Peter B. West" + email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>Properties$AbsolutePosition</title> + <figure src="AbsolutePosition.png" alt="AbsolutePosition diagram"/> + </section> + + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/BorderCommonStyle.png.xml b/src/documentation/content/xdocs/design/alt.design/BorderCommonStyle.png.xml new file mode 100644 index 000000000..e9fad3d77 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/BorderCommonStyle.png.xml @@ -0,0 +1,20 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>BorderCommonStyle diagram</title> + <authors> + <person id="pbw" name="Peter B. West" + email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>Properties$BorderCommonStyle</title> + <figure src="BorderCommonStyle.png" alt="BorderCommonStyle diagram"/> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/PropNames.png.xml b/src/documentation/content/xdocs/design/alt.design/PropNames.png.xml new file mode 100644 index 000000000..6f552009b --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/PropNames.png.xml @@ -0,0 +1,19 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>..fo.PropNames diagram</title> + <person id="pbw" name="Peter B. West" + email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>PropNames.class</title> + <figure src="PropNames.png" alt="PropNames.class diagram"/> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/Properties.png.xml b/src/documentation/content/xdocs/design/alt.design/Properties.png.xml new file mode 100644 index 000000000..8bcf88943 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/Properties.png.xml @@ -0,0 +1,20 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>..fo.Properties diagram</title> + <authors> + <person id="pbw" name="Peter B. West" + email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>Properties.class</title> + <figure src="Properties.png" alt="Properties.class diagram"/> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/PropertyConsts.png.xml b/src/documentation/content/xdocs/design/alt.design/PropertyConsts.png.xml new file mode 100644 index 000000000..2e2763026 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/PropertyConsts.png.xml @@ -0,0 +1,20 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>..fo.PropertyConsts diagram</title> + <authors> + <person id="pbw" name="Peter B. West" + email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>PropertyConsts.class</title> + <figure src="PropertyConsts.png" alt="PropertyConsts.class diagram"/> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/VerticalAlign.png.xml b/src/documentation/content/xdocs/design/alt.design/VerticalAlign.png.xml new file mode 100644 index 000000000..400d43cf7 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/VerticalAlign.png.xml @@ -0,0 +1,20 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>VerticalAlign diagram</title> + <authors> + <person id="pbw" name="Peter B. West" + email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>Properties$VerticalAlign</title> + <figure src="VerticalAlign.png" alt="VerticalAlign diagram"/> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/alt.properties.xml b/src/documentation/content/xdocs/design/alt.design/alt.properties.xml new file mode 100644 index 000000000..a1e7fcf09 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/alt.properties.xml @@ -0,0 +1,172 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>Implementing Properties</title> + <authors> + <person id="pbw" name="Peter B. West" email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>An alternative properties implementation</title> + <note> + The following discussion focusses on the relationship between + Flow Objects in the Flow Object tree, and properties. There + is no (or only passing) discussion of the relationship between + properties and traits, and by extension, between properties + and the Area tree. The discussion is illustrated with some + pseudo-UML diagrams. + </note> + <p> + Property handling is complex and expensive. Varying numbers of + properties apply to individual Flow Objects + <strong>(FOs)</strong> in the <strong>FO + tree </strong> but any property may effectively be + assigned a value on any element of the tree. If that property + is inheritable, its defined value will then be available to + any children of the defining FO. + </p> + <note> + <em>(XSL 1.0 Rec)</em> <strong>5.1.4 Inheritance</strong> + ...The inheritable properties can be placed on any formatting + object. + </note> + <p> + Even if the value is not inheritable, it may be accessed by + its children through the <code>inherit</code> keyword or the + <code>from-parent()</code> core function, and potentially by + any of its descendents through the + <code>from-nearest-specified-value()</code> core function. + </p> + <p> + In addition to the assigned values of properties, almost every + property has an <strong>initial value</strong> which is used + when no value has been assigned. + </p> + <section> + <title>The history problem</title> + <p> + The difficulty and expense of handling properties comes from + this univeral inheritance possibility. The list of properties + which are assigned values on any particular <em>FO</em> + element will not generally be large, but a current value is + required for each property which applies to the <em>FO</em> + being processed. + </p> + <p> + The environment from which these values may be selected + includes, for each <em>FO</em>, for each applicable property, + the value assigned on this <em>FO</em>, the value which + applied to the parent of this <em>FO</em>, the nearest value + specified on an ancestor of this element, and the initial + value of the property. + </p> + </section> + <section> + <title>Data requirement and structure</title> + <p> + This determines the minimum set of properties and associated + property value assignments that is necessary for the + processing of any individual <em>FO</em>. Implicit in this + set is the set of properties and associated values, + effective on the current <em>FO</em>, that were assigned on + that <em>FO</em>. + </p> + <p> + This minimum requirement - the initial value, the + nearest ancestor specified value, the parent computed value + and the value assigned to the current element - + suggests a stack implementation. + </p> + </section> + <section> + <title>Stack considerations</title> + <p> + One possibility is to push to the stack only a minimal set + of required elements. When a value is assigned, the + relevant form or forms of that value (specified, computed, + actual) are pushed onto the stack. As long as each + <em>FO</em> maintains a list of the properties which were + assigned from it, the value can be popped when the focus of + FO processing retreats back up the <em>FO</em> tree. + </p> + <p> + The complication is that, for elements which are not + automatically inherited, when an <em>FO</em> is encountered + which does <strong>not</strong> assign a value to the + property, the initial value must either be already at the + top of the stack or be pushed onto the stack. + </p> + <p> + As a first approach, the simplest procedure may be to push a + current value onto the stack for every element - initial + values for non-inherited properties and the parental value + otherwise. Then perform any processing of assigned values. + This simplifies program logic at what is hopefully a small + cost in memory and processing time. It may be tuned in a + later iteration. + </p> + <section> + <title>Stack implementation</title> + <p> + Initial attempts at this implementation have used + <code>LinkedList</code>s as the stacks, on the assumption + that + </p> + <sl> + <!-- one of (dl sl ul ol li) --> + <li>random access would not be required</li> + <li> + pushing and popping of list elements requires nearly + constant (low) time + </li> + <li> no penalty for first addition to an empty list</li> + <li>efficient access to both bottom and top of stack</li> + </sl> + <p> + However, it may be required to perform stack access + operations from an arbitrary place on the stack, in which + case it would probably be more efficient to use + <code>ArrayList</code>s instead. + </p> + </section> + </section> + <section> + <title>Class vs instance</title> + <p> + An individual stack would contain values for a particular + property, and the context of the stack is the property class + as a whole. The property instances would be represented by + the individual values on the stack. If properties are to be + represented as instantiations of the class, the stack + entries would presumably be references to, or at least + referenced from, individual property objects. However, the + most important information about individual property + instances is the value assigned, and the relationship of + this property object to its ancestors and its descendents. + Other information would include the ownership of a property + instance by a particular <em>FO</em>, and, in the other + direction, the membership of the property in the set of + properties for which an <em>FO</em> has defined values. + </p> + <p> + In the presence of a stack, however, none of this required + information mandates the instantiation of properties. All + of the information mentioned so far can be effectively + represented by a stack position and a link to an + <em>FO</em>. If the property stack is maintained in + parallel with a stack of <em>FOs</em>, even that link is + implicit in the stack position. + </p> + </section> + <p> + <strong>Next:</strong> <link href="classes-overview.html" + >property classes overview.</link> + </p> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/book.xml b/src/documentation/content/xdocs/design/alt.design/book.xml new file mode 100644 index 000000000..2324a6d33 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/book.xml @@ -0,0 +1,37 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//APACHE//DTD Cocoon Documentation Book V1.0//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-cocoon2/src/documentation/xdocs/dtd/book-cocoon-v10.dtd"> + +<book software="FOP" + title="ALT Design" + copyright="@year@ The Apache Software Foundation" + xmlns:xlink="http://www.w3.org/1999/xlink"> + + <menu label="Index"> + <menu-item label="FOP Home" href="../../index.html"/> + <menu-item label="Design" href="../index.html"/> + </menu> + <menu label="About"> + <menu-item label="Alt Design" href="index.html"/> + <menu-item label="co-routines" href="coroutines.html"/> + <menu-item label="galleys" href="galleys.html"/> + <menu-item label="footnotes" href="footnotes.html"/> + <menu-item label="keeps" href="keeps.html"/> + <menu-item label="space-specifiers" href="spaces.html"/> + <menu-item label="alt.properties" href="alt.properties.html"/> + <menu-item label="Classes overview" href="classes-overview.html"/> + <menu-item label="Properties classes" href="properties-classes.html"/> + <menu-item label="Properties" href="Properties.png.html"/> + <menu-item label="PropertyConsts" href="PropertyConsts.png.html"/> + <menu-item label="PropNames" href="PropNames.png.html"/> + <menu-item label="AbsolutePosition" href="AbsolutePosition.png.html"/> + <menu-item label="VerticalAlign" href="VerticalAlign.png.html"/> + <menu-item label="BorderCommonStyle" href="BorderCommonStyle.png.html"/> + <menu-item label="XML parsing" href="xml-parsing.html"/> + <menu-item label="Property parsing" href="propertyExpressions.html"/> + <menu-item label="Compound properties" href="compound-properties.html"/> + <menu-item label="Traits" href="traits.html"/> + <menu-item label="User agent refs" href="user-agent-refs.html"/> + </menu> +</book> + diff --git a/src/documentation/content/xdocs/design/alt.design/classes-overview.xml b/src/documentation/content/xdocs/design/alt.design/classes-overview.xml new file mode 100644 index 000000000..b5e2be845 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/classes-overview.xml @@ -0,0 +1,203 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>Property classes overview</title> + <authors> + <person id="pbw" name="Peter B. West" + email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>Classes overview</title> + <section> + <title>The class of all properties</title> + <p> + If individual properties can have a "virtual reality" on the + stack, where is the stack itself to be instantiated? One + possibility is to have the stacks as <code>static</code> + data structures within the individual property classes. + However, the reduction of individual property instances to + stack entries allows the possibility of further + virtualization of property classes. If the individual + properties can be represented by an integer, i.e. a + <code>static final int</code>, the set of individual + property stacks can be collected together into one array. + Where to put such an overall collection? Creating an + über-class to accommodate everything that applies to + property classes as a whole allows this array to be defined + as a <em><code>static final</code> something[]</em>. + </p> + </section> + <section> + <title>The overall property classes</title> + <p> + This approach has been taken for the experimental code. + Rather than simply creating a overall class containing + common elements of properties and acting as a superclass, + advantage has been taken of the facility for nesting of + top-level classes. All of the individual property classes + are nested within the <code>Properties</code> class. + This has advantages and disadvantages. + </p> + <dl> + <dt>Disadvantages</dt> + <dd> + The file becomes extremely cumbersome. This can cause + problems with "intelligent" editors. E.g. + <em>XEmacs</em> syntax highlighting virtually grinds to a + halt with the current version of this file.<br/> <br/> + + Possible problems with IDEs. There may be speed problems + or even overflow problems with various IDEs. The current + version of this and related files had only been tried with + the <em>[X]Emacs JDE</em> environment, without difficulties + apart from the editor speed problems mentioned + above.<br/> <br/> + + Retro look and feel. Not the done Java thing.<br/> <br/> + </dd> + <dt>Advantages</dt> + <dd> + Everything to do with properties in the one place (more or + less.)<br/> <br/> + + Eliminates the need for a large part of the (sometimes) + necessary evil of code generation. The One Big File of + <code>foproperties.xml</code>, with its ancillary xsl, is + absorbed into the One Bigger File of + <code>Properties.java</code>. The huge advantage of this + is that it <strong>is</strong> Java. + </dd> + </dl> + </section> + <section> + <title>The property information classes</title> + <p> + In fact, in order to keep the size of the file down to more + a more manageable level, the property information classes of + static data and methods have been split tentatively into + three: + </p> + <figure src="PropertyStaticsOverview.png" alt="Top level + property classes"/> + <dl> + <dt><link href="PropNames.html">PropNames</link></dt> + <dd> + Contains an array, <code>propertyNames</code>, of the names of + all properties, and a set of enumeration constants, one + for each property name in the <code>PropertyNames</code> + array. These constants index the name of the properties + in <code>propertyNames</code>, and must be manually kept in + sync with the entries in the array. (This was the last of + the classes split off from the original single class; + hence the naming tiredness.) + <br/> <br/> + </dd> + <dt><link href="PropertyConsts.html">PropertyConsts</link></dt> + <dd> + Contains two basic sets of data:<br/> + Property-indexed arrays and property set + definitions.<br/> <br/> + + <strong>Property-indexed arrays</strong> are elaborations + of the property indexing idea discussed in relation to the + arrays of property stacks. One of the arrays is<br/> <br/> + + <code>public static final LinkedList[] + propertyStacks</code><br/> <br/> + + This is an array of stacks, implemented as + <code>LinkedList</code>s, one for each property.<br/> <br/> + + The other arrays provide indexed access to fields which + are, in most cases, common to all of the properties. An + exception is<br/> <br/> + + <code>public static final Method[] + complexMethods</code><br/> <br/> + + which contains a reference to the method + <code>complex()</code> which is only defined for + properties which have complex value parsing requirements. + It is likely that a similar array will be defined for + properties which allow a value of <em>auto</em>.<br/> <br/> + + The property-indexed arrays are initialized by + <code>static</code> initializers in this class. The + <code>PropNames</code> class and + <code>Properties</code> + nested classes are scanned in order to obtain or derive + the data necessary for initialization.<br/> <br/> + + <strong>Property set definitions</strong> are + <code>HashSet</code>s of properties (represented by + integer constants) which belong to each of the categories + of properties defined. They are used to simplify the + assignment of property sets to individual FOs. + Representative <code>HashSet</code>s include + <em>backgroundProps</em> and + <em>tableProps</em>.<br/> <br/> + </dd> + <dt><link href="Properties.html">Properties</link></dt> + <dd> + <br/> + This class contains only sets of constants for use by the + individual property classes, but it also importantly + serves as a container for all of the property classes, and + some convenience pseudo-property classes.<br/> <br/> + + <strong>Constants sets</strong> include:<br/> <br/> + + <em>Datatype constants</em>. A bitmap set of + integer constants over a possible range of 2^0 to 2^31 + (represented as -2147483648). E.g.<br/> + INTEGER = 1<br/> + ENUM = 524288<br/> <br/> + Some of the definitions are bit-ORed + combinations of the basic values. Used to set the + <em>dataTypes</em> field of the property + classes.<br/> <br/> + + <em>Trait mapping constants</em>. A bitmap set of + integer constants over a possible range of 2^0 to 2^31 + (represented as -2147483648), representing the manner in + which a property maps into a <em>trait</em>. Used to set + the <code>traitMapping</code> field of the property + classes.<br/> <br/> + + <em>Initial value constants</em>. A sequence of + integer constants representing the datatype of the initial + value of a property. Used to set the + <code>initialValueType</code> field of the property + classes.<br/> <br/> + + <em>Inheritance value constants</em>. A sequence + of integer constants representing the way in which the + property is normally inherited. Used to set the + <code>inherited</code> field of the property + classes.<br/> <br/> + + <strong>Nested property classes</strong>. The + <em>Properties</em> class serves as the holding pen for + all of the individual property classes, and for property + pseudo-classes which contain data common to a number of + actual properties, e.g. <em>ColorCommon</em>. + </dd> + </dl> + </section> + <p> + <strong>Previous:</strong> <link href= + "alt.properties.html" >alt.properties</link> + </p> + <p> + <strong>Next:</strong> <link href= + "properties-classes.html" >Properties classes</link> + </p> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/compound-properties.xml b/src/documentation/content/xdocs/design/alt.design/compound-properties.xml new file mode 100644 index 000000000..bd326a4da --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/compound-properties.xml @@ -0,0 +1,218 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>Compound properties</title> + <authors> + <person name="Peter B. West" email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>Compound properties in XSLFO</title> + <table> + <tr> + <th>Property type</th> + <th>Section</th> + <th>Inherited</th> + <th>'inherit'</th> + </tr> + <tr> + <th><length-range></th> + </tr> + <tr> + <th>minimum</th> + </tr> + <tr> + <th>optimum</th> + </tr> + <tr> + <th>maximum</th> + </tr> + <tr> + <td>block-progression-dimension</td> + <td>7.14.1</td> + <td>no</td> + <td>yes</td> + </tr> + <tr> + <td>inline-progression-dimension</td> + <td>7.14.5</td> + <td>no</td> + <td>yes</td> + </tr> + <tr> + <td>leader-length</td> + <td>7.21.4</td> + <td>yes</td> + <td>yes</td> + </tr> + <tr> + <th><length-conditional></th> + </tr> + <tr> + <th>length</th> + </tr> + <tr> + <th>conditionality</th> + </tr> + <tr> + <td>border-after-width</td> + <td>7.7.12</td> + <td>no</td> + <td>yes</td> + </tr> + <tr> + <td>border-before-width</td> + <td>7.7.9</td> + <td>no</td> + <td>yes</td> + </tr> + <tr> + <td>border-end-width</td> + <td>7.7.18</td> + <td>no</td> + <td>yes</td> + </tr> + <tr> + <td>border-start-width</td> + <td>7.7.15</td> + <td>no</td> + <td>yes</td> + </tr> + <tr> + <td>padding-after</td> + <td>7.7.32</td> + <td>no</td> + <td>yes</td> + </tr> + <tr> + <td>padding-before</td> + <td>7.7.31</td> + <td>no</td> + <td>yes</td> + </tr> + <tr> + <td>padding-end</td> + <td>7.7.34</td> + <td>no</td> + <td>yes</td> + </tr> + <tr> + <td>padding-start</td> + <td>7.7.33</td> + <td>no</td> + <td>yes</td> + </tr> + <tr> + <th><length-bp-ip-direction></th> + </tr> + <tr> + <th>block-progression-direction</th> + </tr> + <tr> + <th>inline-progression-direction</th> + </tr> + <tr> + <td>border-separation</td> + <td>7.26.5</td> + <td>yes</td> + <td>yes</td> + </tr> + <tr> + <th><space></th> + </tr> + <tr> + <th>minimum</th> + </tr> + <tr> + <th>optimum</th> + </tr> + <tr> + <th>maximum</th> + </tr> + <tr> + <th>precedence</th> + </tr> + <tr> + <th>conditionality</th> + </tr> + <tr> + <td>letter-spacing</td> + <td>7.16.2</td> + <td>yes</td> + <td>yes</td> + </tr> + <tr> + <td>line-height</td> + <td>7.15.4</td> + <td>yes</td> + <td>yes</td> + </tr> + <tr> + <td>space-after</td> + <td>7.10.6</td> + <td>no</td> + <td>yes</td> + </tr> + <tr> + <td>space-before</td> + <td>7.10.5</td> + <td>no</td> + <td>yes</td> + </tr> + <tr> + <td>space-end</td> + <td>7.11.1</td> + <td>no</td> + <td>yes</td> + </tr> + <tr> + <td>space-start</td> + <td>7.11.2</td> + <td>no</td> + <td>yes</td> + </tr> + <tr> + <td>word-spacing</td> + <td>7.16.8</td> + <td>yes</td> + <td>yes</td> + </tr> + <tr> + <th><keep></th> + </tr> + <tr> + <th>within-line</th> + </tr> + <tr> + <th>within-column</th> + </tr> + <tr> + <th>within-page</th> + </tr> + <tr> + <td>keep-together</td> + <td>7.19.3</td> + <td>yes</td> + <td>yes</td> + </tr> + <tr> + <td>keep-with-next</td> + <td>7.19.4</td> + <td>no</td> + <td>yes</td> + </tr> + <tr> + <td>keep-with-previous</td> + <td>7.19.5</td> + <td>no</td> + <td>yes</td> + </tr> + </table> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/coroutines.xml b/src/documentation/content/xdocs/design/alt.design/coroutines.xml new file mode 100644 index 000000000..31613ef52 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/coroutines.xml @@ -0,0 +1,118 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>Implementing co-routines</title> + <authors> + <person name="Peter B. West" email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>Implementing Co-routines in FOP</title> + <p> + All general page layout systems have to solve the same + fundamental problem: expressing a flow of text with its own + natural structure as a series of pages corresponding to the + physical and logical structure of the output medium. This + simple description disguises many complexities. Version 1.0 + of the Recommendation, in Section 3, <em>Introduction to + Formatting </em>, includes the following comments. + </p> + <note> + [Formatting] comprises several steps, some of which depend on + others in a non-sequential way.<br/> ...and...<br/> + [R]efinement is not necessarily a straightforward, sequential + procedure, but may involve look-ahead, back-tracking, or + control-splicing with other processes in the formatter. + </note> + <p>Section 3.1, <em>Conceptual Procedure</em>, includes:</p> + <note> + The procedure works by processing formatting objects. Each + object, while being processed, may initiate processing in + other objects. While the objects are hierarchically + structured, the processing is not; processing of a given + object is rather like a co-routine which may pass control to + other processes, but pick up again later where it left off. + </note> + <section> + <title>Application of co-routines</title> + <p> + If one looks only at the flow side of the equation, it's + difficult to see what the problem might be. The ordering of + the elements of the flow is preserved in the area tree, and + where elements are in an hierarchical relationship in the + flow, they will generally be in an hierarchical relationship + in the area tree. In such circumstances, the recursive + processing of the flow seems quite natural. + </p> + <p> + The problem becomes more obvious when one thinks about the + imposition of an unrelated page structure over the + hierarchical structure of the document content. Take, e.g., + the processing of a nested flow structure which, at a certain + point, is scanning text and generating line-areas, nested + within other block areas and possibly other line areas. The + page fills in the middle of this process. Processing at the + lowest level in the tree must now suspend, immediately + following the production of the line-area which filled the + page. This same event, however, must also trigger the closing + and flushing to the area tree of every open area of which the last + line-area was a descendant. + </p> + <p> + Once all of these areas have been closed, some dormant process + or processes must wake up, flush the area sub-tree + representing the page, and open a new page sub-tree in the + area tree. Then the whole nested structure of flow objects + and area production must be re-activated, at the point in + processing at which the areas of the previous page were + finalised, but with the new page environment. The most + natural way of expressing the temporal relationship of these + processes is by means of co-routines. + </p> + <p> + Normal sub-routines (methods) display a hierarchical + relationship where process A suspends on invoking process B, + which on termination returns control to A which resumes from + the point of suspension. Co-routines instead have a parallel + relationship. Process A suspends on invoking process B, but + process B also suspends on returning control to process A. To + process B, this return of control appears to be an invocation + of process A. When process A subsequently invokes B and + suspends, B behaves as though its previous invocation of A has + returned, and it resumes from the point of that invocation. + So control bounces between the two, each one resuming where it + left off.<br/><br/> + <strong>Figure 1</strong> + </p> + <figure src="coroutines.png" alt="Co-routine diagram"/> + <p> + For example, think of a page-production method working on a + complex page-sequence-master. + </p> + <source> + void makePages(...) { + ... + while (pageSequence.hasNext()) { + ... + page = generateNextPage(...); + boolean over = flow.fillPage(page); + if (over) return; + } + } + </source> + <p> + The <code>fillPage()</code> method, when it fills a page, will + have unfinished business with the flow, which it will want to + resume at the next call; hence co-routines. One way to + implement them in Java is by threads synchronised on some + common argument-passing object. + </p> + </section> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/footnotes.xml b/src/documentation/content/xdocs/design/alt.design/footnotes.xml new file mode 100644 index 000000000..16179c5f9 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/footnotes.xml @@ -0,0 +1,140 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>Implementing footnotes</title> + <authors> + <person name="Peter B. West" email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>Implementing footnotes in FOP</title> + <p> + Footnotes present difficulties for page layout primarily + because their point of invocation in the flow is different + from their point of appearance in the area tree. All of the + content lines of a footnote may appear on the same page as its + invocation point, all may appear on a following page, or the + lines may be split over a page or pages. (This characteristic + leads to another problem when a footnote overflows the last + page of flow content, but that difficulty will not be + discussed here.) This note considers some aspects of the + implementation of footnotes in a galley-based design. + </p> + <section> + <title>Footnotes and galleys</title> + <p> + In the structure described in the <link href= + "../galleys.html" >introduction to FOP galleys</link>, + footnotes would be pre-processed as galleys themselves, but + they would remain attached as subtrees to their points of + invocation in the main text. Allocation to a + footnote-reference-area would only occur in the resolution + to Area nodes. + </p> + <p> + When footnotes are introduced, the communication between + galleys and layout manager, as mentioned <link href= + "../galleys.html#pre-processing" >above</link>, would be + affected. The returned information would two b-p-d values: + the primary line-area b-p-d impact and the footnote b-p-d + impact. The distinction is necessary for two reasons; to + alert the layout manager to the first footnote of the page, + and because the footnote b-p-d will always impact the + main-reference-area b-p-d, whereas the primary inline-area + may not, e.g. in the case of multiple span-areas. + </p> + </section> + <section> + <title>Multiple columns and footnotes</title> + <note> + A possible method for multi-column layout and balancing + with footnotes, using a galley-based approach. + </note> + <p> + This note assumes a galley, as discussed <link href= + "../galleys.html" >elsewhere</link>, flowing text with + footnotes and possibly other blocks into a possibly + multi-column area. The logic of flowing into multiple + columns is trivially applied to a single column. The galley + is manipulated within the context of the <em>layout + tree</em>. + </p> + <p> + Associated with the galley are two sets of data. + One contains the maps of all "natural" break-points and + the of all hyphenation break-points. This set is + constructed at the time of construction of the galley and + is a constant for a given galley. The second contains + dynamic data which represents one possible attempt to lay + out the galley. There may be multiple sets of such data + to reflect varying attempts. The data of this set are, + essentially, representations of line-areas, with the supporting + information necessary to determine these line-areas. + </p> + <p> + The line-area data includes the boundaries within the + galley of each line-area, the boundaries of each column + and the boundaries of the "page", or main area. When a + line-area boundary occurs at a hyphenation point, a + "virtual hyphen" is assumed and accounted for in the + i-p-d. As mentioned, individual footnote galleys will + hang from the parent galley. The associated data of the + footnote galleys is similar: a once-only break-points map, + and one or more line-area maps. No column boundaries are + required, but a page boundary is required at the end of + the last footnote or where a footnote breaks across a page + boundary. + </p> + <p> + A number of b-p-d values are also maintained. For each + line-area, the b-p-d, the main area b-p-d increment, the + footnote b-p-d increment and the footnote's page-related + b-p-d increment are required. The main-area b-p-d + increments for any particular line-area are dependent on + the column position of the line-area. Total b-p-d's are + also kept: total footnote b-p-d, total main area b-p-d, + and totals for each column.<br/><br/> + <strong>Figure 1</strong> Columns before first footnote. + </p> + <figure src="initial-column-values.png" alt="Columns before + first footnote"/> + </section> + <section> + <title>Balancing columns</title> + <p> + <strong>Figure 2</strong> Adding a line area with first + footnote. + </p> + <figure src="line-area-5.png" + alt="Columns after adding first footnote"/> + <p> + Columns are balanced dynamically in the galley preliminary + layout. While the galley retains its basic linear + structure, the accompanying data structures accomplish + column distribution and balancing. As each line-area is + added, the columns are re-balanced. <strong>N.B.</strong> + This re-balancing involves only some of the dynamic data + associated with the participating galley(s). The data + structures associating breakpoints with the beginning and + end of individual line areas does not change in + re-balancing; only the association of line-area with column, + and, possibly, the various impact values for each line-area. + <br/><br/> + <strong>Figure 3</strong> Adding a line area with next + footnote. + </p> + <figure src="line-area-6.png" + alt="Columns after adding next footnote"/> + </section> + <section> + <title>Layout managers in the flow of control</title> + <note>To be developed.</note> + </section> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/galleys.xml b/src/documentation/content/xdocs/design/alt.design/galleys.xml new file mode 100644 index 000000000..f7ae3cbb9 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/galleys.xml @@ -0,0 +1,216 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>Galleys</title> + <authors> + <person name="Peter B. West" email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>Layout galleys in FOP</title> + <section> + <title>Galleys in Lout</title> + <p> + Jeffrey H. Kingston, in <link href = + "http://snark.niif.spb.su/~uwe/lout/design.pdf" ><em>The + Design and Implementation of the Lout Document Formatting + Language</em> Section 5</link>, describes the + <strong>galley</strong> abstraction which he implemented in + <em>Lout</em>. A document to be formatted is a stream of + text and symbols, some of which are <strong>receptive + symbols</strong>. The output file is the first receptive + symbol; the formatting document is the first galley. The + archetypical example of a receptive symbol is + <strong>@FootPlace</strong> and its corresponding galley + definition, <strong>@FootNote</strong>. + </p> + <p> + Each galley should be thought of as a concurrent process, and + each is associated with a semaphore (or synchronisation + object.) Galleys are free to "promote" components into + receptive targets as long as</p> + <ul> + <li> + an appropriate target has been encountered in the file, + </li> + <li> + the component being promoted contains no unresolved galley + targets itself, and + </li> + <li> + there is sufficient room for the galley component at the + target. + </li> + </ul> + <p> + If these conditions are not met, the galley blocks on its + semaphore. When conditions change so that further progress + may be possible, the semaphore is signalled. Note that the + galleys are a hierarchy, and that the processing and + promotion of galley contents happens <em>bottom-up</em>. + </p> + </section> + <section> + <title>Some features of galleys</title> + <p> + It is essential to note that galleys are self-managing; they + are effectively layout <em>bots</em> which require only a + receptive area. If a galley fills a receptive area (say, at + the completion of a page), the galley will wait on its + semaphore, and will remain stalled until a new receptive + area is uncovered in the continued processing (say, as the + filled page is flushed to output and a new empty page is + generated.) + </p> + <p> + Difficulties with this approach become evident when there + are mutual dependencies between receptive areas which + require negotiation between the respective galleys, and, in + some cases, arbitrary deadlock breaking when there is no + clear-cut resolution to conflicting demands. Footnote + processing and side floats are examples. A thornier example + is table column layout in <em>auto</em> mode, where the + column widths are determined by the contents. In + implementing galleys in FOP, these difficulties must be + taken into account, and some solutions proposed. + </p> + <p> + Galleys model the whole of the process of creating the final + formatted output; the document as a whole is regarded as a + galley which flushes in to the output file. + </p> + </section> + <section> + <title>The layout tree</title> + <anchor id="layout-tree"/> + <p> + This proposal for implementing galleys in FOP makes use of a + <strong>layout tree</strong>. As with the <link href= + "../layout.html" >layout managers</link><em></em> already + proposed, the layout tree acts as a bridge between the <link + href= "../fotree.html" >FO Tree</link> and the <link href= + "../areatree.html" >Area Tree</link>. If the elements of + the FO Tree are FO nodes, and the elements of the Area Tree + are Area nodes, representing areas to be drawn on the output + medium, the elements of the layout tree are <strong>galley + nodes</strong> and <strong>area tree fragments</strong>. + The area tree fragments are the final stages of the + resolution of the galleys; the output of the galleys will be + inserted directly into the Area Tree. The tree structure + makes it clear that the whole of the formatting process in + FOP, under this model, is a hierarchical series of galleys. + The dynamic data comes from fo:flow and fo:static-content, + and the higher-level receptive areas are derived from the + <em>layout-master-set</em>. + </p> + </section> + <section> + <title>Processing galleys</title> + <p> + Galleys are processed in two basic processing environments: + </p> + <section> + <title>Inline- and block-progression dimensions known</title> + <p> + The galley at set-up is provided with both an + <em>inline-progression-dimension</em> (<em>i-p-d</em>) and + a <em>block-progression-dimension</em> (<em>b-p-d</em>). + In this case, no further intervention is necessary to lay + out the galley. The galley has the possibility of laying + itself out, creating all necessary area nodes. This does + not preclude the possibility that some children of this + galley will not be able to be so directly laid out, and + will fall into the second category. + </p> + <p> + While the option of "automatic" layout exists, to use + such a method would relinquish the possibility of + monitoring the results of such layout and performing + fine-tuning. + </p> + </section> + <section> + <title>Inline- ior block-progression-dimensions unknown</title> + <p> + The galley cannot immediately be provided with an i-p-d + ior a b-p-d. This will occur in some of the difficult + cases mentioned earlier. In these cases, the parent + galley acts as a layout manager, similar to the sense used + in <link href= "../layout.html" >another + discussion</link>. The children, lacking full receptive + area dimensions, will proceed with galley pre-processing, + a procedure which will, of necessity, be followed + recursively by all of its children down to the atomic + elements of the galley. These atomic elements are the + individual <em>fo:character</em> nodes and images of fixed + dimensions. + </p> + </section> + </section> + <section> + <title>Galley pre-processing</title> + <anchor id="pre-processing"/> + <p> + Galley pre-processing involves the spatial resolution of + objects from the flows to the greatest extent possible + without information on the dimensions of the target area. + Line-areas have a block progression dimension which is + determined by their contents. To achieve full generality in + layouts of indeterminate dimensions, the contents of + line-areas should be laid out as though their inline + progression dimension were limited only by their content. + In terms of inline-areas, galleys would process text and + resolve the dimensions of included images. Text would be + collected into runs with the same alignment + characteristics. In the process, all possible "natural" and + hyphenation break-points can be determined. Where a + line-area contains mixed fonts or embedded images, the b-p-d + of the individual line-areas which are eventually stacked + will, in general, depend on the line break points, but the + advantage of this approach is that such actual selections + can be backed out and new break points selected with a + minimum of re-calculation. This can potentially occur + whenever a first attempt at page layout is backed out. + <br/><br/> + <strong>Figure 1</strong> + </p> + <figure src="galley-preprocessing.png" alt="Galley + pre-processing diagram"/> + <p> + Once this pre-processing has been achieved, it is + envisaged that a layout manager might make requests to the + galley of its ability to fill an area of a given + inline-progression-dimension. A positive response would + be accompanied by the block-progression-dimension. The + other possibilities are a partial fill, which would also + require b-p-d data, and a failure due to insufficient + i-p-d, in which case the minimum i-p-d requirement would + be returned. Note that decisions about the + actual dimensions of line-areas to be filled can be + deferred until all options have been tested. + </p> + <p> + The other primary form of information provided by a + pre-processed galley is its minimum and maximum i-p-d, so + that decisions can be made by the parent on the spacing of + table columns. Apart from information requests, + higher-level processes can either make requests of the + galleys for chunks of nominated sizes, or simply provide the + galley with an i-p-d and b-p-d, which will trigger the + flushing of the galley components into Area nodes. Until + they have flushed, the galleys must be able to respond to a + sequence of information requests, more or less in the manner + of a request iterator, and separately manage the flushing of + objects into the area tree. The purpose of the "request + iterator" would be to support "incremental" information + requests like <em>getNextBreakPosition</em>. + </p> + </section> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/index.xml b/src/documentation/content/xdocs/design/alt.design/index.xml new file mode 100644 index 000000000..08e60f059 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/index.xml @@ -0,0 +1,84 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>FOP Alternative Design</title> + <subtitle>Alternative Design Approach to FOP</subtitle> + <version>$Revision$ $Name$</version> + <authors> + <person name="Peter B. West" email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>Alternative Design</title> + <p> + This section of the FOP web site contains notes on approaches + to an alternative design for FOP. The individual documents + here are fragmentary, being notes of particular issues, + without an overall framework as yet. + </p> + <p> + The main aims of this redesign effort are: + </p> + <ul> + <li>full conformance with the Recommendation</li> + <li>increased performance</li> + <li>reduced memory footprint</li> + <li>no limitation on the size of files</li> + </ul> + <p> + In order to achieve these aims, the primary areas + of design interest are: + </p> + <ul> + <li> + Representing properties, for most purposes, as integers. + </li> + <li> + Distributing FOP processing over a number of threads with + single-point downstream communication and flow control by + means of traditional producer/consumer queues. The threads + so far under consideration are: + <ul> + <li>XML parser</li> + <li>FO tree builder</li> + <li>layout engine</li> + <li>Area tree builder</li> + </ul> + </li> + <li> + Representing trees with explicit Tree objects, rather than + as implicit relationships among other objects. + </li> + <li> + Caching integrated into the tree node access methods. + </li> + </ul> + <section> + <title>Status and availability</title> + <p> + The <em>ALT DESIGN</em> effort is not taking place on the + main line of development, represented by the <em>HEAD</em> + tag on the CVS trunk. The source is available via the + FOP_0-20-0_Alt-Design tag. This code has only a crude, + non-<em>Ant</em> build environment, and is expected only to + compile at this stage. Only the parser stage and the first + stage of FO tree building is present. However, the first + example of producer/consumer binding is working, the Tree + class with inner Tree.Node and inner + Tree.Node.<em>iterators</em> classes are available and + working. Property handling is quite advanced, and is likely + to be almost complete some time in July, 2002. + </p> + <p> + Only <link href="mailto:pbwest@powerup.com.au">Peter + West</link> is working on the ALT DESIGN sub-project. + </p> + </section> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/keeps.xml b/src/documentation/content/xdocs/design/alt.design/keeps.xml new file mode 100644 index 000000000..ffb29f5f1 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/keeps.xml @@ -0,0 +1,110 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>Keeps and breaks</title> + <authors> + <person name="Peter B. West" email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>Keeps and breaks in layout galleys</title> + <p> + The <link href= "galleys.html" >layout galleys</link> and the + <link href= "galleys.html#layout-tree" >layout tree</link> + which is their context have been discussed elsewhere. Here we + discuss a possible method of implementing keeps and breaks + within the context of layout galleys and the layout tree. + </p> + <section> + <title>Breaks</title> + <p> + Breaks may be handled by inserting a column- or page-break + pseudo-object into the galley stream. For break-before, the + object would be inserted before the area in which the flow + object, to which the property is attached, is leading. If + the flow object is leading in no ancestor context, the + pseudo-object is inserted before the object itself. + Corresponding considerations apply for break-after. + Selection of the position for these objects will be further + examined in the discussion on keeps. + </p> + </section> + <section> + <title>Keeps</title> + <p> + Conceptually, all keeps can be represented by a + keep-together pseudo-area. The keep-together property + itself is expressed during layout by wrapping all of the + generated areas in a keep-together area. Keep-with-previous + on formatting object A becomes a keep-together area spanning + the first non-blank normal area leaf node, L, generated by A + or its offspring, and the last non-blank normal area leaf + node preceding L in the area tree. Likewise, keep-with-next + on formatting object A becomes a keep-together area spanning + the last non-blank normal area leaf node, L, generated by A + or its offspring, and the first non-blank normal area leaf + node following L in the area tree. + <br/>TODO REWORK THIS for block vs inline + </p> + <p> + The obvious problem with this arrangement is that the + keep-together area violate the hierarachical arrangement of + the layout tree. They form a concurrent structure focussed + on the leaf nodes. This seems to be the essential problem + of handling keep-with-(previous/next); that it cuts across + the otherwise tree-structured flow of processing. Such + problems are endemic in page layout. + </p> + <p> + In any case, it seems that the relationships between areas + that are of interest in keep processing need some form of + direct expression, parallel to the layout tree itself. + Restricting ourselves too block-level elements, and looking + only at the simple block stacking cases, we get a diagram + like the attached PNG. In order to track the relationships + through the tree, we need four sets of links. + </p> + <p> + <strong>Figure 1</strong> + </p> + <anchor id="Figure1"/> + <figure src="block-stacking.png" alt="Simple block-stacking + diagram"/> + <p> + The three basic links are: + </p> + <ul> + <!-- one of (dl sl ul ol li) --> + <li>Leading edge to leading edge of first normal child.</li> + <li>Trailing edge to leading edge of next normal + sibling.</li> + <li>Trailing edge to trailing edge of parent.</li> + </ul> + <p> + Superimposed on the basic links are bridging links which + span adjacent sets of links. These spanning links are the + tree violators, and give direct access to the areas which + are of interest in keep processing. They could be + implemented as double-linked lists, either within the layout + tree nodes or as separate structures. Gaps in the spanning + links are joined by simply reproducing the single links, as + in the diagram. The whole layout tree for a page is + effectively threaded in order of interest, as far as keeps + are concerned. + </p> + <p> + The bonus of this structure is that it looks like a superset + of the stacking constraints. It gives direct access to all + sets of adjacent edges and sets of edges whose space + specifiers need to be resolved. Fences can be easily enough + detected during the process of space resolution. + </p> + </section> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/properties-classes.xml b/src/documentation/content/xdocs/design/alt.design/properties-classes.xml new file mode 100644 index 000000000..3345cadfa --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/properties-classes.xml @@ -0,0 +1,143 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>Properties$classes</title> + <authors> + <person name="Peter B. West" email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>fo.Properties and the nested properties classes</title> + <figure src="PropertyClasses.png" alt="Nested property and + top-level classes"/> + <section> + <title>Nested property classes</title> + <p> + Given the intention that individual properties have only a + <em>virtual</em> instantiation in the arrays of + <code>PropertyConsts</code>, these classes are intended to + remain as repositories of static data and methods. The name + of each property is entered in the + <code>PropNames.propertyNames</code> array of + <code>String</code>s, and each has a unique integer constant + defined, corresponding to the offset of the property name in + that array. + </p> + <section> + <title>Fields common to all classes</title> + <dl> + <dt><code>final int dataTypes</code></dt> + <dd> + This field defines the allowable data types which may be + assigned to the property. The value is chosen from the + data type constants defined in <code>Properties</code>, and + may consist of more than one of those constants, + bit-ORed together. + </dd> + <dt><code>final int traitMapping</code></dt> + <dd> + This field defines the mapping of properties to traits + in the <code>Area tree</code>. The value is chosen from the + trait mapping constants defined in <code>Properties</code>, + and may consist of more than one of those constants, + bit-ORed together. + </dd> + <dt><code>final int initialValueType</code></dt> + <dd> + This field defines the data type of the initial value + assigned to the property. The value is chosen from the + initial value type constants defined in + <code>Properties</code>. + </dd> + <dt><code>final int inherited</code></dt> + <dd> + This field defines the kind of inheritance applicable to + the property. The value is chosen from the inheritance + constants defined in <code>Properties</code>. + </dd> + </dl> + </section> + <section> + <title>Datatype dependent fields</title> + <dl> + <dt>Enumeration types</dt> + <dd> + <strong><code>final String[] enums</code></strong><br/> + This array contains the <code>NCName</code> text + values of the enumeration. In the current + implementation, it always contains a null value at + <code>enum[0]</code>.<br/> <br/> + + <strong><code>final String[] + enumValues</code></strong><br/> When the number of + enumeration values is small, + <code>enumValues</code> is a reference to the + <code>enums</code> array.<br/> <br/> + + <strong><code>final HashMap + enumValues</code></strong><br/> When the number of + enumeration values is larger, + <code>enumValues</code> is a + <code>HashMap</code> statically initialized to + contain the integer constant values corresponding to + each text value, indexed by the text + value.<br/> <br/> + + <strong><code>final int</code></strong> + <em><code>enumeration-constants</code></em><br/> A + unique integer constant is defined for each of the + possible enumeration values.<br/> <br/> + </dd> + <dt>Many types: + <code>final</code> <em>datatype</em> + <code>initialValue</code></dt> + <dd> + When the initial datatype does not have an implicit + initial value (as, for example, does type + <code>AUTO</code>) the initial value for the property is + assigned to this field. The type of this field will + vary according to the <code>initialValueType</code> + field. + </dd> + <dt>AUTO: <code>PropertyValueList auto(property, + list)></code></dt> + <dd> + When <em>AUTO</em> is a legal value type, the + <code>auto()</code> method must be defined in the property + class.<br/> + <em>NOT YET IMPLEMENTED.</em> + </dd> + <dt>COMPLEX: <code>PropertyValueList complex(property, + list)></code></dt> + <dd> + <em>COMPLEX</em> is specified as a value type when complex + conditions apply to the selection of a value type, or + when lists of values are acceptable. To process and + validate such a property value assignment, the + <code>complex()</code> method must be defined in the + property class. + </dd> + </dl> + </section> + </section> + <section> + <title>Nested property pseudo-classes</title> + <p> + The property pseudo-classes are classes, like + <code>ColorCommon</code> which contain values, particularly + <em>enums</em>, which are common to a number of actual + properties. + </p> + </section> + <p> + <strong>Previous:</strong> <link href= "classes-overview.html" + >property classes overview.</link> + </p> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/propertyExpressions.xml b/src/documentation/content/xdocs/design/alt.design/propertyExpressions.xml new file mode 100644 index 000000000..90d67349f --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/propertyExpressions.xml @@ -0,0 +1,343 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>Property Expression Parsing</title> + <authors> + <person id="pbw" name="Peter B. West" email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>Property expression parsing</title> + <note> + The following discussion of the experiments with alternate + property expression parsing is very much a work in progress, + and subject to sudden changes. + </note> + <p> + The parsing of property value expressions is handled by two + closely related classes: <code>PropertyTokenizer</code> and its + subclass, <code>PropertyParser</code>. + <code>PropertyTokenizer</code>, as the name suggests, handles + the tokenizing of the expression, handing <em>tokens</em> + back to its subclass, + <code>PropertyParser</code>. <code>PropertyParser</code>, in + turn, returns a <code>PropertyValueList</code>, a list of + <code>PropertyValue</code>s. + </p> + <p> + The tokenizer and parser rely in turn on the datatype + definition from the <code>org.apache.fop.datatypes</code> + package and the datatype <code>static final int</code> + constants from <code>PropertyConsts</code>. + </p> + <section> + <title>Data types</title> + <p> + The data types currently defined in + <code>org.apache.fop.datatypes</code> include: + </p> + <table> + <tr><th colspan="2">Numbers and lengths</th></tr> + <tr> + <th>Numeric</th> + <td colspan="3"> + The fundamental numeric data type. <em>Numerics</em> of + various types are constructed by the classes listed + below. + </td> + </tr> + <tr> + <td/> + <th colspan="3">Constructor classes for <em>Numeric</em></th> + </tr> + <tr> + <td/><td>Angle</td> + <td colspan="2">In degrees(deg), gradients(grad) or + radians(rad)</td> + </tr> + <tr> + <td/><td>Ems</td> + <td colspan="2">Relative length in <em>ems</em></td> + </tr> + <tr> + <td/><td>Frequency</td> + <td colspan="2">In hertz(Hz) or kilohertz(kHz)</td> + </tr> + <tr> + <td/><td>IntegerType</td><td/> + </tr> + <tr> + <td/><td>Length</td> + <td colspan="2">In centimetres(cm), millimetres(mm), + inches(in), points(pt), picas(pc) or pixels(px)</td> + </tr> + <tr> + <td/><td>Percentage</td><td/> + </tr> + <tr> + <td/><td>Time</td> + <td>In seconds(s) or milliseconds(ms)</td> + </tr> + <tr><th colspan="2">Strings</th></tr> + <tr> + <th>StringType</th> + <td colspan="3"> + Base class for data types which result in a <em>String</em>. + </td> + </tr> + <tr> + <td/><th>Literal</th> + <td colspan="2"> + A subclass of <em>StringType</em> for literals which + exceed the constraints of an <em>NCName</em>. + </td> + </tr> + <tr> + <td/><th>MimeType</th> + <td colspan="2"> + A subclass of <em>StringType</em> for literals which + represent a mime type. + </td> + </tr> + <tr> + <td/><th>UriType</th> + <td colspan="2"> + A subclass of <em>StringType</em> for literals which + represent a URI, as specified by the argument to + <em>url()</em>. + </td> + </tr> + <tr> + <td/><th>NCName</th> + <td colspan="2"> + A subclass of <em>StringType</em> for literals which + meet the constraints of an <em>NCName</em>. + </td> + </tr> + <tr> + <td/><td/><th>Country</th> + <td>An RFC 3066/ISO 3166 country code.</td> + </tr> + <tr> + <td/><td/><th>Language</th> + <td>An RFC 3066/ISO 639 language code.</td> + </tr> + <tr> + <td/><td/><th>Script</th> + <td>An ISO 15924 script code.</td> + </tr> + <tr><th colspan="2">Enumerated types</th></tr> + <tr> + <th>EnumType</th> + <td colspan="3"> + An integer representing one of the tokens in a set of + enumeration values. + </td> + </tr> + <tr> + <td/><th>MappedEnumType</th> + <td colspan="2"> + A subclass of <em>EnumType</em>. Maintains a + <em>String</em> with the value to which the associated + "raw" enumeration token maps. E.g., the + <em>font-size</em> enumeration value "medium" maps to + the <em>String</em> "12pt". + </td> + </tr> + <tr><th colspan="2">Colors</th></tr> + <tr> + <th>ColorType</th> + <td colspan="3"> + Maintains a four-element array of float, derived from + the name of a standard colour, the name returned by a + call to <em>system-color()</em>, or an RGB + specification. + </td> + </tr> + <tr><th colspan="2">Fonts</th></tr> + <tr> + <th>FontFamilySet</th> + <td colspan="3"> + Maintains an array of <em>String</em>s containing a + prioritized list of possibly generic font family names. + </td> + </tr> + <tr><th colspan="2">Pseudo-types</th></tr> + <tr> + <td colspan="4"> + A variety of pseudo-types have been defined as + convenience types for frequently appearing enumeration + token values, or for other special purposes. + </td> + </tr> + <tr> + <th>Inherit</th> + <td colspan="3"> + For values of <em>inherit</em>. + </td> + </tr> + <tr> + <th>Auto</th> + <td colspan="3"> + For values of <em>auto</em>. + </td> + </tr> + <tr> + <th>None</th> + <td colspan="3"> + For values of <em>none</em>. + </td> + </tr> + <tr> + <th>Bool</th> + <td colspan="3"> + For values of <em>true/false</em>. + </td> + </tr> + <tr> + <th>FromNearestSpecified</th> + <td colspan="3"> + Created to ensure that, when associated with + a shorthand, the <em>from-nearest-specified-value()</em> + core function is the sole component of the expression. + </td> + </tr> + <tr> + <th>FromParent</th> + <td colspan="3"> + Created to ensure that, when associated with + a shorthand, the <em>from-parent()</em> + core function is the sole component of the expression. + </td> + </tr> + </table> + </section> + <section> + <title>Tokenizer</title> + <p> + The tokenizer returns one of the following token + values: + </p> + <source> + static final int + EOF = 0 + ,NCNAME = 1 + ,MULTIPLY = 2 + ,LPAR = 3 + ,RPAR = 4 + ,LITERAL = 5 + ,FUNCTION_LPAR = 6 + ,PLUS = 7 + ,MINUS = 8 + ,MOD = 9 + ,DIV = 10 + ,COMMA = 11 + ,PERCENT = 12 + ,COLORSPEC = 13 + ,FLOAT = 14 + ,INTEGER = 15 + ,ABSOLUTE_LENGTH = 16 + ,RELATIVE_LENGTH = 17 + ,TIME = 18 + ,FREQ = 19 + ,ANGLE = 20 + ,INHERIT = 21 + ,AUTO = 22 + ,NONE = 23 + ,BOOL = 24 + ,URI = 25 + ,MIMETYPE = 26 + // NO_UNIT is a transient token for internal use only. It is + // never set as the end result of parsing a token. + ,NO_UNIT = 27 + ; + </source> + <p> + Most of these tokens are self-explanatory, but a few need + further comment. + </p> + <dl> + <dt>AUTO</dt> + <dd> + Because of its frequency of occurrence, and the fact that + it is always the <em>initial value</em> for any property + which supports it, AUTO has been promoted into a + pseudo-type with its on datatype class. Therefore, it is + also reported as a token. + </dd> + <dt>NONE</dt> + <dd> + Similarly to AUTO, NONE has been promoted to a pseudo-type + because of its frequency. + </dd> + <dt>BOOL</dt> + <dd> + There is a <em>de facto</em> boolean type buried in the + enumeration types for many of the properties. It had been + specified as a type in its own right in this code. + </dd> + <dt>MIMETYPE</dt> + <dd> + The property <code>content-type</code> introduces this + complication. It can have two values of the form + <strong>content-type:</strong><em>mime-type</em> + (e.g. <code>content-type="content-type:xml/svg"</code>) or + <strong>namespace-prefix:</strong><em>prefix</em> + (e.g. <code>content-type="namespace-prefix:svg"</code>). The + experimental code reduces these options to the payload + in each case: an <code>NCName</code> in the case of a + namespace prefix, and a MIMETYPE in the case of a + content-type specification. <code>NCName</code>s cannot + contain a "/". + </dd> + </dl> + </section> + <section> + <title>Parser</title> + <p> + The parser retuns a <code>PropertyValueList</code>, + necessary because of the possibility that a list of + <code>PropertyValue</code> elements may be returned from the + expressions of soem properties. + </p> + <p> + <code>PropertyValueList</code>s may contain + <code>PropertyValue</code>s or other + <code>PropertyValueList</code>s. This latter provision is + necessitated for the peculiar case of of + <em>text-shadow</em>, which may contain whitespace separated + sublists of either two or three elements, separated from one + another by commas. To accommodate this peculiarity, comma + separated elements are added to the top-level list, while + whitespace separated values are always collected into + sublists to be added to the top-level list. + </p> + <p> + Other special cases include the processing of the core + functions <code>from-parent()</code> and + <code>from-nearest-specified-value()</code> when these + function calls are assigned to a shorthand property, or used + with a shorthand property name as an argument. In these + cases, the function call must be the sole component of the + expression. The pseudo-element classes + <code>FromParent</code> and + <code>FromNearestSpecified</code> are generated in these + circumstances so that an exception will be thrown if they + are involved in expression evaluation with other + components. (See Rec. Section 5.10.4 Property Value + Functions.) + </p> + <p> + The experimental code is a simple extension of the existing + parser code, which itself borrowed heavily from James + Clark's XT processor. + </p> + </section> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/spaces.xml b/src/documentation/content/xdocs/design/alt.design/spaces.xml new file mode 100644 index 000000000..f2426347b --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/spaces.xml @@ -0,0 +1,179 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>Keeps and space-specifiers</title> + <authors> + <person name="Peter B. West" email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>Keeps and space-specifiers in layout galleys</title> + <p> + The <link href= "galleys.html" >layout galleys</link> and the + <link href= "galleys.html#layout-tree" >layout tree</link> + which is the context of this discussion have been discussed + elsewhere. A <link href="keeps.html">previous document</link> + discussed data structures which might facilitate the lining of + blocks necessary to implement keeps. Here we discuss the + similarities between the keep data structures and those + required to implement space-specifier resolution. + </p> + <section> + <title>Space-specifiers</title> + <note> + <strong>4.3 Spaces and Conditionality</strong> + ... Space-specifiers occurring in sequence may interact with + each other. The constraint imposed by a sequence of + space-specifiers is computed by calculating for each + space-specifier its associated resolved space-specifier in + accordance with their conditionality and precedence. + </note> + <note> + 4.2.5 Stacking Constraints ... The intention of the + definitions is to identify areas at any level of the tree + which have only space between them. + </note> + <p> + The quotations above are pivotal to understanding the + complex discussion of spaces with which they are associated, + all of which exists to enable the resolution of adjacent + <space>s. It may be helpful to think of <em>stacking + constraints</em> as <em><space>s interaction</em> or + <em><space>s stacking interaction</em>. + </p> + </section> + <section> + <title>Block stacking constraints</title> + <p> + In the discussion of block stacking constraints in Section + 4.2.5, the notion of <em>fence</em> is introduced. For + block stacking constraints, a fence is defined as either a + reference-area boundary or a non-zero padding or border + specification. Fences, however, do not come into play + when determining the constraint between siblings. (See + <link href="#Figure1">Figure 1</link>.) + </p> + <p><strong>Figure 1</strong></p><anchor id="Figure1"/> + <figure src="block-stacking-constraints.png" + alt="block-stacking-constraints.png"/> + <note> + Figure 1 assumes a block-progression-direction of top to + bottom. + </note> + <p> + In <link href="#Figure1">Diagram a)</link>, block A has + non-zero padding and borders, in addition to non-zero + spaces. Note, however, that the space-after of A is + adjacent to the space-before of block P, so borders and + padding on these siblings have no impact on the interaction + of their <space>s. The stacking constraint A,P is + indicated by the red rectangle enclosing the space-after of + A and the space-before of P. + </p> + <p> + In <link href="#Figure1">Diagram b)</link>, block B is the + first block child of P. The stacking constraint A,P is as + before; the stacking constraint P,B is the space-before of + B, as indicated by the enclosing magenta rectangle. In this + case, however, the non-zero border of P prevents the + interaction of the A,P and P,B stacking constraints. There + is a <em>fence-before</em> P. The fence is notional; it has + no precise location, as the diagram may lead one to believe. + </p> + <p> + In <link href="#Figure1">Diagram c)</link>, because of the + zero-width borders and padding on block P, the fence-before + P is not present, and the adjacent <space>s of blocks + A, P and B are free to interact. In this case, the stacking + constraints A,P and P,B are as before, but now there is an + additional stacking constraint A,B, represented by the light + brown rectangle enclosing the other two stacking + constraints. + </p> + <p> + The other form of fence occurs when the parent block is a + reference area. Diagram b) of <link href="#Figure2">Figure + 2</link> illustrates this situation. Block C is a + reference-area, involving a 180 degree change of + block-progression-direction (BPD). In the diagram, the + inner edge of block C represents the content rectangle, with + its changed BPD. The thicker outer edge represents the + outer boundary of the padding, border and spaces of C. + </p> + <p> + While not every reference-area will change the + inline-progression-direction (IPD) and BPD of an area, no + attempt is made to discriminate these cases. A + reference-area always a fence. The fence comes into play in + analogous circumstances to non-zero borders or padding. + Space resolution between a reference area and its siblings + is not affected. + </p> + <p> + In the case of <link href="#Figure2">Diagram b)</link>, + these are block stacking constraints B,C and C,A. Within + the reference-area, bock stacing constraints C,D and E,C are + unaffected. However, the fence prevents block stacking + constraints such as B,E or D,A. When there is a change of + BPD, as <link href="#Figure2">Diagram b)</link> makes + visually obvious, it is difficult to imagine which blocks + would have such a constraint, and what the ordering of the + constraint would be. + </p> + <p><strong>Figure 2</strong></p> + <anchor id="Figure2"/> + <figure src="block-stacking-keeps.png" + alt="block-stacking-keeps.png"/> + </section> + <section> + <title>Keep relationships between blocks</title> + <p> + As complicated as space-specifiers become when + reference-areas are involved, the keep relationships as + described in the <link + href="keeps.html#Figure1">keeps</link> document, are + unchanged. This is also illustrated in <link + href="#Figure2">Figure 2</link>. Diagram b) shows the + relative placement of blocks in the rendered output when a + 180 degree change of BPD occurs, with blocks D and E + stacking in the reverse direction to blocks B and C. + Diagram c) shows what happens when the page is too short to + accommodate the last block. D is still laid out, but E is + deferred to the next page. + </p> + <p> + Note that this rendering reality is expressed directly in + the area (and layout) tree view. Consequently, any keep + relationships expressed as links threading through the + layout tree will not need to be modified to account for + reference-area boundaries, as is the case with similar + space-specifier edge links. E.g., a keep-with-next + condition on block B can be resolved along the path of these + links (B->C->D) into a direct relationship of B->D, + irrespective of the reference-area boundary. + </p> + <p> + While the same relationships obviously hold when a reference + area induces no change of BPD, the situation for BPD changes + perpendicular to the parent's BPD may not be so clear. In + general, it probably does not make much sense to impose keep + conditions across such a boundary, but there seems to be + nothing preventing such conditions. They can be dealt with + in the same way, i.e., the next leaf block linked in area + tree order must be the next laid out. If a keep condition + is in place, an attempt must be made to meet it. A number + of unusual considerations would apply, e.g. the minimum + inline-progression-dimension of the first leaf block within + the reference-area as compared to the minimum IPD of + subsequent blocks, but <em>prima facie</em>, the essential + logic of the keeps links remains. + </p> + </section> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/traits.xml b/src/documentation/content/xdocs/design/alt.design/traits.xml new file mode 100644 index 000000000..365540060 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/traits.xml @@ -0,0 +1,369 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>Traits</title> + <authors> + <person name="Peter B. West" email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>Traits</title> + <table> + <tr> + <th>Trait</th> + <th>Applies to</th> + <th>Refs</th> + <th>Derived from</th> + </tr> + <tr> + <th>Common Traits</th> + </tr> + <tr> + <td>block-progression-direction</td> + <td>All areas</td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#area-common" + >4.2.2 Common Traits</link><br/> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#writing-mode" + >7.27.7 writing-mode</link> + </td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#reference-orientation" + >7.27.7 reference-orientation</link> + </td> + </tr> + <tr> + <td>inline-progression-direction</td> + <td>All areas</td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#area-common" + >4.2.2 Common Traits</link><br/> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#writing-mode" + >7.27.7 writing-mode</link> + </td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#reference-orientation" + >7.27.7 reference-orientation</link> + </td> + </tr> + <tr> + <td>shift-direction</td> + <td>Inline areas</td> + </tr> + <tr> + <td>glyph-orientation</td> + <td>Glyph-areas</td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#area-common" + >4.2.2 Common Traits</link><br/> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#area-glyph" + >4.6.2 Glyph-areas</link><br/> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#area-linebuild" + >4.7.2 Line-building</link><br/> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#rend-intrinsic" + >4.9.5 Intrinsic Marks</link><br/> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#font-model" + >7.8.1 Fonts and Font Data</link><br/> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#writing-mode-related" + >7.27 Writing-mode-related Properties</link> + </td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#glyph-orientation-horizontal" + >7.27.2 glyph-orientation-horizontal</link><br/> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#glyph-orientation-vertical" + >7.27.3 glyph-orientation-vertical</link><br/> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#direction" + >7.27.1 direction</link><br/> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#writing-mode" + >7.27.7 writing-mode</link> + </td> + </tr> + <tr> + <td>is-reference-area</td> + <td>All areas</td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice5.html#section-N6691-Non-property-Based-Trait-Generation" + >5.6 Non-property Based Trait Generation</link> + </td> + <td> + Set "true" on:<br/> + simple-page-master<br/> + title<br/> + region-body<br/> + region-before<br/> + region-after<br/> + region-start<br/> + region-end<br/> + block-container<br/> + inline-container<br/> + table<br/> + table-caption<br/> + table-cell + </td> + </tr> + <tr> + <td>is-viewport-area</td> + <td></td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#area-common" + >4.2.2 Common Traits</link> + </td> + </tr> + <tr> + <td>top-position</td> + </tr> + <tr> + <td>bottom-position</td> + </tr> + <tr> + <td>left-position</td> + </tr> + <tr> + <td>right-position</td> + </tr> + <tr> + <td>left-offset</td> + </tr> + <tr> + <td>top-offset</td> + </tr> + <tr> + <td>is-first</td> + </tr> + <tr> + <td>is-last</td> + </tr> + <tr> + <td>generated-by</td> + </tr> + <tr> + <td>returned-by</td> + </tr> + <tr> + <td>nominal-font</td> + </tr> + <tr> + <td>blink</td> + <td></td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice5.html#refine-text-decoration" + >5.5.6 Text-decoration Property + </link> + </td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#text-decoration" + >7.16.4 "text-decoration" + </link> + </td> + </tr> + <tr> + <td>underline-score</td> + <td></td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice5.html#refine-text-decoration" + >5.5.6 Text-decoration Property + </link> + </td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#text-decoration" + >7.16.4 "text-decoration" + </link> + </td> + </tr> + <tr> + <td>underline-score-color</td> + <td></td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice5.html#refine-text-decoration" + >5.5.6 Text-decoration Property + </link> + </td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#text-decoration" + >7.16.4 "text-decoration" + </link> + </td> + </tr> + <tr> + <td>overline-score</td> + <td></td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice5.html#refine-text-decoration" + >5.5.6 Text-decoration Property + </link> + </td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#text-decoration" + >7.16.4 "text-decoration" + </link> + </td> + </tr> + <tr> + <td>overline-score-color</td> + <td></td> + + <td> + <link href= + "http://www.w3.org/TR/xsl/slice5.html#refine-text-decoration" + >5.5.6 Text-decoration Property + </link> + </td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#text-decoration" + >7.16.4 "text-decoration" + </link> + </td> + </tr> + <tr> + <td>through-score</td> + <td></td> + + <td> + <link href= + "http://www.w3.org/TR/xsl/slice5.html#refine-text-decoration" + >5.5.6 Text-decoration Property + </link> + </td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#text-decoration" + >7.16.4 "text-decoration" + </link> + </td> + </tr> + <tr> + <td>through-score-color</td> + <td></td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice5.html#refine-text-decoration" + >5.5.6 Text-decoration Property + </link> + </td> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice7.html#text-decoration" + >7.16.4 "text-decoration" + </link> + </td> + </tr> + <tr> + <th>Other Indirectly Derived Traits</th> + </tr> + <tr> + <td>alignment-point</td> + <td/> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#area-intro" + >4.1 Introduction</link> + </td> + </tr> + <tr> + <td>alignment-baseline</td> + <td/> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#area-intro" + >4.1 Introduction</link> + </td> + </tr> + <tr> + <td>baseline-shift</td> + <td/> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#area-intro" + >4.1 Introduction</link> + </td> + </tr> + <tr> + <td>dominant-baseline-identifier</td> + <td/> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#area-intro" + >4.1 Introduction</link> + </td> + </tr> + <tr> + <td>actual-baseline-table</td> + <td/> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#area-intro" + >4.1 Introduction</link> + </td> + </tr> + <tr> + <td>start-intrusion-adjustment</td> + <td/> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#area-intro" + >4.1 Introduction</link> + </td> + </tr> + <tr> + <td>end-intrusion-adjustment</td> + <td/> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#area-intro" + >4.1 Introduction</link> + </td> + </tr> + <tr> + <td>page-number</td> + <td/> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#area-intro" + >4.1 Introduction</link> + </td> + </tr> + <tr> + <td>script</td> + <td/> + <td> + <link href= + "http://www.w3.org/TR/xsl/slice4.html#area-intro" + >4.1 Introduction</link> + </td> + </tr> + </table> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/user-agent-refs.xml b/src/documentation/content/xdocs/design/alt.design/user-agent-refs.xml new file mode 100644 index 000000000..47fe45f94 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/user-agent-refs.xml @@ -0,0 +1,909 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>User agent refs</title> + <authors> + <person name="Peter B. West" email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>User Agent references in XSLFO</title> + <section> + <title>4.9.2 Viewport Geometry</title> + <p> + If the block-progression-dimension of the reference-area is + larger than that of the viewport-area and the overflow trait + for the reference-area is scroll, then the + inline-scroll-amount and block-scroll-amount are determined + by a scrolling mechanism, if any, provided by the + <strong>user agent</strong>. Otherwise, both are zero. + </p> + </section> + <section> + <title>5.1.3 Actual Values</title> + <p> + A computed value is in principle ready to be used, but a + user agent may not be able to make use of the value in a + given environment. For example, a <strong>user + agent</strong> may only be able to render borders with + integer pixel widths and may, therefore, have to adjust the + computed width to an integral number of media pixels. + </p> + </section> + <section> + <title>5.5.7 Font Properties</title> + <p> + There is no XSL mechanism to specify a particular font; + instead, a selected font is chosen from the fonts available + to the <strong>User Agent</strong> based on a set of + selection criteria. The selection criteria are the following + font properties: "font-family", "font-style", + "font-variant", "font-weight", "font-stretch", and + "font-size", plus, for some formatting objects, one or more + characters. + </p> + </section> + <section> + <title>5.9.13.1 Pixels</title> + <p> + If the <strong>User Agent</strong> chooses a measurement for + a 'px' that does not match an integer number of device dots + in each axis it may produce undesirable effects... + </p> + </section> + <section> + <title>5.10.4 Property Value Functions</title> + <section> + <title>Function: object merge-property-values( NCName)</title> + <p> + The merge-property-values function returns a value of the + property whose name matches the argument, or if omitted + for the property for which the expression is being + evaluated. The value returned is the specified value on + the last fo:multi-property-set, of the parent + fo:multi-properties, that applies to the <strong>User + Agent</strong> state. If there is no such value, the + computed value of the parent fo:multi-properties is + returned... + </p> + <p> + The test for applicability of a <strong>User + Agent</strong> state is specified using the "active-state" + property. + </p> + </section> + </section> + <section> + <title>6.3 Formatting Objects Summary</title> + <section> + <title>multi-property-set</title> + <p> + The fo:multi-property-set is used to specify an + alternative set of formatting properties that, dependent + on a <strong>User Agent</strong> state, are applied to the + content. + </p> + </section> + <section> + <title>title</title> + <p> + The fo:title formatting object is used to associate a + title with a given page-sequence. This title may be used + by an interactive <strong>User Agent</strong> to identify + the pages. For example, the content of the fo:title can be + formatted and displayed in a "title" window or in a "tool + tip". + </p> + </section> + </section> + <section> + <title>6.4.1.2 Page-masters</title> + <p> + ... When pages are used with a <strong>User Agent</strong> + such as a Web browser, it is common that the each document + has only one page. The viewport used to view the page + determines the size of the page. When pages are placed on + non-interactive media, such as sheets of paper, pages + correspond to one or more of the surfaces of the paper. + </p> + </section> + <section> + <title>6.4.20 fo:title</title> + <section> + <title>Common Usage:</title> + <p> + ... This title may be used by an interactive <strong>User + Agent</strong> to identify the pages. + </p> + </section> + </section> + <section> + <title>6.6.3 fo:character</title> + <section> + <title>Constraints:</title> + <p> + The dimensions of the areas are determined by the font + metrics for the glyph. + </p> + <p> + When formatting an fo:character with a + "treat-as-word-space" value of "true", the <strong>User + Agent</strong> may use a different method for determining + the inline-progression-dimension of the area. + </p> + </section> + </section> + <section> + <title>6.9 Dynamic Effects: Link and Multi Formatting + Objects</title> + <section> + <title>6.9.1 Introduction</title> + <p> + Dynamic effects, whereby user actions (including + <strong>User Agent</strong> state) can influence the + behavior and/or representation of portions of a document, + can be achieved through the use of the formatting objects + included in this section: + </p> + <ul> + <li>One-directional single-target links.</li> + <li> + The ability to switch between the display of two or more + formatting object subtrees. This can be used for, e.g., + expandable/collapsible table of contents, display of an + icon or a full table or graphic. + </li> + <li> + The ability to switch between different property values, + such as color or font-weight, depending on a + <strong>User Agent</strong> state, such as "hover". + </li> + </ul> + </section> + </section> + <section> + <title>6.10 Out-of-Line Formatting Objects</title> + <section> + <title>6.10.1.3 Conditional Sub-Regions</title> + <p> + ... There may be limits on how much space conditionally + generated areas can borrow from the + region-reference-area. It is left to the <strong>user + agent</strong> to decide these limits. + </p> + <p> + ... An interactive <strong>user agent</strong> may choose + to create "hot links" to the footnotes from the + footnote-citation, or create "hot links" to the + before-floats from an implicit citation, instead of + realizing conditional sub-regions. + </p> + </section> + </section> + <section> + <title>6.10.2 fo:float</title> + <section> + <title>Constraints:</title> + <p> + ... The <strong>user agent</strong> may make its own + determination, after taking into account the intrusion + adjustments caused by one or more overlapping side-floats, + that the remaining space in the + inline-progression-direction is insufficient for the next + side-float or normal block-area. The <strong>user + agent</strong> may address this by causing the next + side-float or normal block-area to "clear" one of the + relevant side-floats, as described in the "clear" property + description, so the intrusion adjustment is sufficiently + reduced. Of the side-floats that could be cleared to meet + this constraint, the side-float that is actually cleared + must be the one whose after-edge is closest to the + before-edge of the parent reference-area. + </p> + <p> + The <strong>user agent</strong> may determine sufficiency + of space by using a fixed length, or by some heuristic + such as whether an entire word fits into the available + space, or by some combination, in order to handle text and + images. + </p> + </section> + </section> + <section> + <title>6.10.3 fo:footnote</title> + <section> + <title>Constraints:</title> + <p> + ... The second block-area and any additional block-areas + returned by an fo:footnote must be placed on the + immediately subsequent pages to the page containing the + first block-area returned by the fo:footnote, before any + other content is placed. If a subsequent page does not + contain a region-body, the <strong>user agent</strong> + must use the region-master of the last page that did + contain a region-body to hold the additional block-areas. + </p> + </section> + </section> + <section> + <title>7.3 Reference Rectangle for Percentage Computations</title> + <p>...</p> + <section> + <title>Exceptions ...</title> + <p> + 5. When the absolute-position is "fixed", the containing + block is defined by the nearest ancestor viewport area. If + there is no ancestor viewport area, the containing block + is defined by the <strong>user agent</strong>. + </p> + </section> + </section> + <section> + <title>7.6.5 "pause-after" 7.6.6 "pause-before" 7.6.17 "voice-family"</title> + <p>Initial: depends on <strong>user agent</strong></p> + </section> + <section> + <title>7.7.1 "background-attachment"</title> + <section> + <title>fixed</title> + <p> + ... <strong>User agents</strong> may treat fixed as + scroll. However, it is recommended they interpret fixed + correctly, at least for the HTML and BODY elements, since + there is no way for an author to provide an image only for + those browsers that support fixed. + </p> + </section> + </section> + <section> + <title>7.7.9 "border-before-width"</title> + <section> + <title><length-conditional></title> + <p> + ... If border-before-width is specified using one of the + width keywords the .conditional component is set to + "discard" and the .length component to a <strong>User + Agent</strong> dependent length. + </p> + </section> + </section> + <section> + <title>7.7.19 "border-top-color"</title> + <section> + <title><color></title> + <p> + ... If an element's border color is not specified with a + "border" property, <strong>user agents</strong> must use + the value of the element's "color" property as the + computed value for the border color. + </p> + </section> + </section> + <section> + <title>7.7.20 "border-top-style"</title> + <p> + Conforming HTML <strong>user agents</strong> may interpret + 'dotted', 'dashed', 'double', 'groove', 'ridge', 'inset', + and 'outset' to be 'solid'. + </p> + </section> + <section> + <title>7.7.21 "border-top-width"</title> + <section> + <title>thin ... medium ... thick ...</title> + <p> + ... The interpretation of the first three values depends + on the <strong>user agent</strong>. + </p> + </section> + </section> + <section> + <title>7.8.2 "font-family"</title> + <p>Initial: depends on <strong>user agent</strong></p> + </section> + <section> + <title>7.8.3 "font-selection-strategy"</title> + <p> + There is no XSL mechanism to specify a particular font; + instead, a selected font is chosen from the fonts available + to the <strong>User Agent</strong> based on a set of + selection criteria. The selection criteria are the following + font properties: "font-family", "font-style", + "font-variant", "font-weight", "font-stretch", and + "font-size", plus, for some formatting objects, one or more + characters. + </p> + <p> + ... This fallback may be to seek a match using a + <strong>User Agent</strong> default "font-family", or it may + be a more elaborate fallback strategy where, for example, + "Helvetica" would be used as a fallback for "Univers". + </p> + <p> + If no match has been found for a particular character, there + is no selected font and the <strong>User Agent</strong> + should provide a visual indication that a character is not + being displayed (for example, using the 'missing character' + glyph). + </p> + </section> + <section> + <title>7.8.4 "font-size"</title> + <section> + <title><absolute-size></title> + <p> + An <absolute-size> keyword refers to an entry in a + table of font sizes computed and kept by the <strong>user + agent</strong>. Possible values are:<br/>[ xx-small | + x-small | small | medium | large | x-large | xx-large ] + </p> + </section> + <section> + <title><relative-size></title> + <p> + A <relative-size> keyword is interpreted relative to + the table of font sizes and the font size of the parent + element. Possible values are:<br/>[ larger | smaller + ]<br/>For example, if the parent element has a font size + of "medium", a value of "larger" will make the font size + of the current element be "large". If the parent element's + size is not close to a table entry, the <strong>user + agent</strong> is free to interpolate between table + entries or round off to the closest one. The <strong>user + agent</strong> may have to extrapolate table values if the + numerical value goes beyond the keywords. + </p> + </section> + <section> + <title><length></title> + <p> + A length value specifies an absolute font size (that is + independent of the <strong>user agent</strong>'s font + table). + </p> + </section> + </section> + <section> + <title>7.8.8 "font-variant"</title> + <section> + <title>small-caps</title> + <p> + ... If a genuine small-caps font is not available, + <strong>user agents</strong> should simulate a small-caps + font... + </p> + </section> + </section> + <section> + <title>7.8.9 "font-weight"</title> + <section> + <title>XSL modifications to the CSS definition:</title> + <p> + ... The association of other weights within a family to + the numerical weight values is intended only to preserve + the ordering of weights within that family. <strong>User + agents</strong> must map names to values in a way that + preserves visual order; a face mapped to a value must not + be lighter than faces mapped to lower values. There is no + guarantee on how a <strong>user agent</strong> will map + fonts within a family to weight values. However, the + following heuristics... + </p> + </section> + </section> + <section> + <title>7.13.1 "alignment-adjust"</title> + <section> + <title>auto</title> + <p> + ... If the baseline-identifier does not exist in the + baseline-table for the glyph or other inline-area, then + the <strong>User Agent</strong> may either use heuristics + to determine where that missing baseline would be or may + use the dominant-baseline as a fallback. + </p> + </section> + </section> + <section> + <title>7.13.3 "baseline-shift"</title> + <section> + <title>sub/super</title> + <p> + ... Because in most fonts the subscript position is + normally given relative to the "alphabetic" baseline, the + <strong>User Agent</strong> may compute the effective + position for sub/superscripts <em>[sub: spec typo!]</em> + when some other baseline is dominant. ... If there is no + applicable font data the <strong>User Agent</strong> may + use heuristics to determine the offset. + </p> + </section> + </section> + <section> + <title>7.13.5 "dominant-baseline"</title> + <p> + ... If there is no baseline-table in the nominal font or if + the baseline-table lacks an entry for the desired baseline, + then the <strong>User Agent</strong> may use heuristics to + determine the position of the desired baseline. + </p> + </section> + <section> + <title>7.14.11 "scaling-method"</title> + <section> + <title>auto</title> + <p> + The <strong>User Agent</strong> is free to choose either + resampling, integer scaling, or any other scaling method. + </p> + </section> + <section> + <title>integer-pixels</title> + <p> + The <strong>User Agent</strong> should scale the image + such that each pixel in the original image is scaled to + the nearest integer number of device-pixels that yields an + image less-then-or-equal-to the image size derived from + the content-height, content-width, and scaling properties. + </p> + </section> + <section> + <title>resample-any-method</title> + <p> + The <strong>User Agent</strong> should resample the + supplied image to provide an image that fills the size + derived from the content-height, content-width, and + scaling properties. The <strong>user agent</strong> may + use any sampling method. + </p> + </section> + <p> + ... This is defined as a preference to allow the + <strong>user agent</strong> the flexibility to adapt to + device limitations and to accommodate over-constrained + situations involving min/max dimensions and scale factors. + </p> + </section> + <section> + <title>7.14.12 "width"</title> + <p> + ... The width of a replaced element's box is intrinsic and + may be scaled by the <strong>user agent </strong> if the + value of this property is different than 'auto'. + </p> + </section> + <section> + <title>7.15.4 "line-height"</title> + <section> + <title>normal</title> + <p> + Tells <strong>user agents</strong> to set the computed + value to a "reasonable" value based on the font size of + the element. + </p> + </s3> + <p> + ... When an element contains text that is rendered in more + than one font, <strong>user agents</strong> should determine + the "line-height" value according to the largest font size. + </p> + </section> + <section> + <title>7.15.9 "text-align"</title> + <p> + ... The actual justification algorithm used is <strong>user + agent</strong> and written language dependent.<br/> + Conforming <strong>user agents</strong> may interpret the + value 'justify' as 'left' or 'right', depending on whether + the element's default writing direction is left-to-right or + right-to-left, respectively. + </p> + </section> + <section> + <title>7.15.11 "text-indent"</title> + <p> + ... <strong>User agents</strong> should render this + indentation as blank space. + </p> + </section> + <section> + <title>7.16.2 "letter-spacing"</title> + <section> + <title>normal</title> + <p> + The spacing is the normal spacing for the current + font. This value allows the <strong>user agent</strong> to + alter the space between characters in order to justify + text. + </p> + </section> + <section> + <title><length></title> + <p> + This value indicates inter-character space in addition to + the default space between characters. Values may be + negative, but there may be implementation-specific + limits. <strong>User agents</strong> may not further + increase or decrease the inter-character space in order to + justify text. + </p> + </section> + <p> + Character-spacing algorithms are <strong>user agent</strong> + dependent. Character spacing may also be influenced by + justification (see the "text-align" property).<br/> When the + resultant space between two characters is not the same as + the default space, <strong>user agents</strong> should not + use ligatures.<br/> Conforming <strong>user agents</strong> + may consider the value of the 'letter-spacing' property to + be 'normal'. + </p> + <section> + <title>XSL modifications to the CSS definition:</title> + <p> + ... For "normal": .optimum = "the normal spacing for the + current font" / 2, .maximum = auto, .minimum = auto, + .precedence = force, and .conditionality = discard. A + value of auto for a component implies that the limits are + <strong>User Agent</strong> specific. + </p> + <p> + ... The CSS statement that "Conforming <strong>user + agents</strong> may consider the value of the + 'letter-spacing' property to be 'normal'." does not apply + in XSL, if the <strong>User Agent</strong> implements the + "Extended" property set. + </p> + <p> + ... The algorithm for resolving the adjusted values + between word spacing and letter spacing is <strong>User + Agent</strong> dependent. + </p> + </section> + </section> + <section> + <title>7.16.4 "text-decoration"</title> + <p> + ... If the element has no content or no text content (e.g., + the IMG element in HTML), <strong>user agents</strong> must + ignore this property. + </p> + <section> + <title>blink</title> + <p> + ... Conforming <strong>user agents</strong> are not + required to support this value. + </p> + </section> + </section> + <section> + <title>7.16.6 "text-transform"</title> + <p> + ... Conforming <strong>user agents</strong> may consider the + value of "text-transform" to be "none" for characters that + are not from the ISO Latin-1 repertoire and for elements in + languages for which the transformation is different from + that specified by the case-conversion tables of Unicode or + ISO 10646. + </p> + </section> + <section> + <title>7.16.8 "word-spacing"</title> + <p> + ... Word spacing algorithms are <strong>user + agent</strong>-dependent. + </p> + <section> + <title>XSL modifications to the CSS definition:</title> + <p> + ... The algorithm for resolving the adjusted values + between word spacing and letter spacing is <strong>User + Agent</strong> dependent. + </p> + </section> + </section> + <section> + <title>7.17.1 "color"</title> + <p>Initial: depends on <strong>user agent</strong></p> + </section> + <section> + <title>7.17.3 "rendering-intent"</title> + <section> + <title>auto</title> + <p> + This is the default behavior. The <strong>User + Agent</strong> determines the best intent based on the + content type. For image content containing an embedded + profile, it shall be assumed that the intent specified + within the profile is the desired intent. Otherwise, the + <strong>user agent</strong> shall use the current profile + and force the intent, overriding any intent that might be + stored in the profile itself. + </p> + </section> + </section> + <section> + <title>7.20.2 "overflow"</title> + <section> + <title>scroll</title> + <p> + This value indicates that the content is clipped and that + if the <strong>user agent</strong> uses a scrolling + mechanism that is visible on the screen (such as a scroll + bar or a panner), that mechanism should be displayed for a + box whether or not any of its content is clipped. + </p> + </section> + <section> + <title>auto</title> + <p> + The behavior of the "auto" value is <strong>user + agent</strong> dependent, but should cause a scrolling + mechanism to be provided for overflowing boxes. + </p> + </section> + </section> + <section> + <title>7.21.2 "leader-pattern"</title> + <section> + <title>dots</title> + <p> + ... The choice of dot character is dependent on the + <strong>user agent</strong>. + </p> + </section> + </section> + <section> + <title>7.21.4 "leader-length"</title> + <p> + ... <strong>User agents</strong> may choose to use the value + of "leader-length.optimum" to determine where to break the + line, then use the minimum and maximum values during line + justification. + </p> + </section> + <section> + <title>7.25.11 "media-usage"</title> + <section> + <title>auto</title> + <p> + The <strong>User Agent</strong> determines which value of + "media-usage" (other than the "auto" value) is used. The + <strong>User Agent</strong> may consider the type of media + on which the presentation is to be placed in making this + determination.<br/> NOTE:<br/> For example, the + <strong>User Agent </strong> could use the following + decision process. If the media is not continuous and is of + fixed bounded size, then the "paginate" (described below) + is used. Otherwise, the "bounded-in-one-dimension" is + used. + </p> + </section> + <section> + <title>bounded-in-one-dimension</title> + <p> + ... It is an error if more or less than one of + "page-height" or "page-width" is specified on the first + page master that is used. The <strong>User Agent</strong> + may recover as follows:... + </p> + </section> + <section> + <title>unbounded</title> + <p> + Only one page is generated per fo:page-sequence descendant + from the fo:root. Neither "page-height" nor "page-width" + may be specified on any page master that is used. If a + value is specified for either property, it is an error and + a <strong>User Agent</strong> may recover by ignoring the + specified value. ... + </p> + </section> + </section> + <section> + <title>7.25.13 "page-height"</title> + <section> + <title>auto</title> + <p> + The "page-height" shall be determined, in the case of + continuous media, from the size of the <strong>User + Agent</strong> window... + </p> + </section> + <section> + <title>NOTE:</title> + <p> + A <strong>User Agent</strong> may provide a way to declare + the media for which formatting is to be done. This may be + different from the media on which the formatted result is + viewed. For example, a browser <strong>User Agent</strong> + may be used to preview pages that are formatted for sheet + media. In that case, the size calculation is based on the + media for which formatting is done rather than the media + being currently used. + </p> + </section> + </section> + <section> + <title>7.25.15 "page-width"</title> + <section> + <title>auto</title> + <p> + The "page-width" shall be determined, in the case of + continuous media, from the size of the <strong>User + Agent</strong> window... + </p> + </section> + </section> + <section> + <title>7.26.5 "border-separation"</title> + <s3 title="<length-bp-ip-direction>"> + <p> + ... Rows, columns, row groups, and column groups cannot + have borders (i.e., <strong>user agents</strong> must + ignore the border properties for those elements). + </p> + </section> + </section> + <section> + <title>7.26.7 "caption-side"</title> + <p> + ... For a caption that is on the left or right side of a + table box, on the other hand, a value other than "auto" for + "width" sets the width explicitly, but "auto" tells the + <strong>user agent</strong> to chose a "reasonable width". + </p> + </section> + <section> + <title>7.27.2 "glyph-orientation-horizontal"</title> + <section> + <title><angle></title> + <p> + ... The <strong>User Agent</strong> shall round the value + of the angle to the closest of the permitted values. + </p> + </section> + </section> + <section> + <title>7.27.3 "glyph-orientation-vertical"</title> + <section> + <title>auto</title> + <p> + ... The determination of which characters should be + auto-rotated may vary across <strong>User Agents</strong>. + </p> + </section> + <section> + <title><angle></title> + <p> + ... The <strong>User Agent</strong> shall round the value + of the angle to the closest of the permitted values. + </p> + </section> + </section> + <section> + <title>7.27.6 "unicode-bidi"</title> + <section> + <title>XSL modifications to the CSS definition:</title> + <p> + ... Fallback:<br/> If it is not possible to present the + characters in the correct order, then the + <strong>UserAgent </strong> should display either a + 'missing character' glyph or display some indication that + the content cannot be correctly rendered. + </p> + </section> + </section> + <section> + <title>7.28.1 "content-type"</title> + <p> + ... This property specifies the content-type and may be used + by a <strong>User Agent</strong> to select a rendering + processor for the object. + </p> + <section> + <title>auto</title> + <p> + No identification of the content-type. The <strong>User + Agent</strong> may determine it by "sniffing" or by other + means. + </p> + </section> + </section> + <section> + <title>7.29.5 "border-color"</title> + <p> + ... If an element's border color is not specified with a + "border" property, <strong>user agents</strong> must use the + value of the element's "color" property as the computed + value for the border color. + </p> + </section> + <section> + <title>7.29.9 "border-spacing"</title> + <p> + ... Rows, columns, row groups, and column groups cannot have + borders (i.e., <strong>user agents</strong> must ignore the + border properties for those elements). + </p> + </section> + <section> + <title>7.29.13 "font"</title> + <p> + ... If no font with the indicated characteristics exists on + a given platform, the <strong>user agent</strong> should + either intelligently substitute (e.g., a smaller version of + the "caption" font might be used for the "small-caption" + font), or substitute a <strong>user agent</strong> default + font. + </p> + </section> + <section> + <title>7.29.19 "pause"</title> + <p>Initial: depends on <strong>user agent</strong></p> + </section> + <section> + <title>7.29.21 "size"</title> + <p> + ... Relative page boxes allow <strong>user agents</strong> + to scale a document and make optimal use of the target size. + </p> + <p> + ... <strong>User agents</strong> may allow users to control + the transfer of the page box to the sheet (e.g., rotating an + absolute page box that's being printed). + </p> + <ul> + <li> + Rendering page boxes that do not fit a target sheet<br/> + If a page box does not fit the target sheet dimensions, + the <strong>user agent</strong> may choose to: + <ul> + <li> + Rotate the page box 90 degrees if this will make the + page box fit. + </li> + <li>Scale the page to fit the target.</li> + </ul> + The <strong>user agent</strong> should consult the user + before performing these operations. + </li> + <li> + Positioning the page box on the sheet<br/> When the page + box is smaller than the target size, the <strong>user + agent</strong> is free to place the page box anywhere on + the sheet. + </li> + </ul> + </section> + <section> + <title>7.29.23 "white-space"</title> + <section> + <title>normal</title> + <p> + This value directs <strong>user agents</strong> to + collapse sequences of whitespace, and break lines as + necessary to fill line boxes. ... + </p> + </section> + <section> + <title>pre</title> + <p> + This value prevents <strong>user agents</strong> from + collapsing sequences of whitespace. ... + </p> + </section> + <p> + ... Conforming <strong>user agents</strong> may ignore the + 'white-space' property in author and user style sheets but + must specify a value for it in the default style sheet. + </p> + </section> + </section> + </body> +</document> + diff --git a/src/documentation/content/xdocs/design/alt.design/xml-parsing.xml b/src/documentation/content/xdocs/design/alt.design/xml-parsing.xml new file mode 100644 index 000000000..6151dae74 --- /dev/null +++ b/src/documentation/content/xdocs/design/alt.design/xml-parsing.xml @@ -0,0 +1,228 @@ +<?xml version="1.0" standalone="no"?> +<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.1//EN" + "http://cvs.apache.org/viewcvs.cgi/*checkout*/xml-forrest/src/resources/schema/dtd/document-v11.dtd"> + +<document> + <header> + <title>Integrating XML Parsing</title> + <authors> + <person name="Peter B. West" email="pbwest@powerup.com.au"/> + </authors> + </header> + <body> + <section> + <title>An alternative parser integration</title> + <p> + This note proposes an alternative method of integrating the + output of the SAX parsing of the Flow Object (FO) tree into + FOP processing. The pupose of the proposed changes is to + provide for better decomposition of the process of analysing + and rendering an fo tree such as is represented in the output + from initial (XSLT) processing of an XML source document. + </p> + <section> + <title>Structure of SAX parsing</title> + <p> + Figure 1 is a schematic representation of the process of SAX + parsing of an input source. SAX parsing involves the + registration, with an object implementing the + <code>XMLReader</code> interface, of a + <code>ContentHandler</code> which contains a callback + routine for each of the event types encountered by the + parser, e.g., <code>startDocument()</code>, + <code>startElement()</code>, <code>characters()</code>, + <code>endElement()</code> and <code>endDocument()</code>. + Parsing is initiated by a call to the <code>parser()</code> + method of the <code>XMLReader</code>. Note that the call to + <code>parser()</code> and the calls to individual callback + methods are synchronous: <code>parser()</code> will only + return when the last callback method returns, and each + callback must complete before the next is called.<br/><br/> + <strong>Figure 1</strong> + </p> + <figure src="SAXParsing.png" alt="SAX parsing schematic"/> + <p> + In the process of parsing, the hierarchical structure of the + original FO tree is flattened into a number of streams of + events of the same type which are reported in the sequence + in which they are encountered. Apart from that, the API + imposes no structure or constraint which expresses the + relationship between, e.g., a startElement event and the + endElement event for the same element. To the extent that + such relationship information is required, it must be + managed by the callback routines. + </p> + <p> + The most direct approach here is to build the tree + "invisibly"; to bury within the callback routines the + necessary code to construct the tree. In the simplest case, + the whole of the FO tree is built within the call to + <code>parser()</code>, and that in-memory tree is subsequently + processed to (a) validate the FO structure, and (b) + construct the Area tree. The problem with this approach is + the potential size of the FO tree in memory. FOP has + suffered from this problem in the past. + </p> + </section> + <section> + <title>Cluttered callbacks</title> + <p> + On the other hand, the callback code may become increasingly + complex as tree validation and the triggering of the Area + tree processing and subsequent rendering is moved into the + callbacks, typically the <code>endElement()</code> method. + In order to overcome acute memory problems, the FOP code was + recently modified in this way, to trigger Area tree building + and rendering in the <code>endElement()</code> method, when + the end of a page-sequence was detected. + </p> + <p> + The drawback with such a method is that it becomes difficult + to detemine the order of events and the circumstances in + which any particular processing events are triggered. When + the processing events are inherently self-contained, this is + irrelevant. But the more complex and context-dependent the + relationships are among the processing elements, the more + obscurity is engendered in the code by such "side-effect" + processing. + </p> + </section> + <section> + <title>From passive to active parsing</title> + <p> + In order to solve the simultaneous problems of exposing the + structure of the processing and minimising in-memory + requirements, the experimental code separates the parsing of + the input source from the building of the FO tree and all + downstream processing. The callback routines become + minimal, consisting of the creation and buffering of + <code>XMLEvent</code> objects as a <em>producer</em>. All + of these objects are effectively merged into a single event + stream, in strict event order, for subsequent access by the + FO tree building process, acting as a + <em>consumer</em>. In itself, this does not reduce the + footprint. This occurs when the approach is generalised to + modularise FOP processing.<br/><br/> <strong>Figure 2</strong> + </p> + <figure src="XML-event-buffer.png" alt="XML event buffer"/> + <p> + The most useful change that this brings about is the switch + from <em>passive</em> to <em>active</em> XML element + processing. The process of parsing now becomes visible to + the controlling process. All local validation requirements, + all object and data structure building, is initiated by the + process(es) <em>get</em>ting from the queue - in the case + above, the FO tree builder. + </p> + </section> + <section> + <title>XMLEvent methods</title> + <anchor id="XMLEvent-methods"/> + <p> + The experimental code uses a class <strong>XMLEvent</strong> + to provide the objects which are placed in the queue. + <em>XMLEvent</em> includes a variety of methods to access + elements in the queue. Namespace URIs encountered in + parsing are maintined in a <code>static</code> + <code>HashMap</code> where they are associated with a unique + integer index. This integer value is used in the signature + of some of the access methods. + </p> + <dl> + <dt>XMLEvent getEvent(SyncedCircularBuffer events)</dt> + <dd> + This is the basis of all of the queue access methods. It + returns the next element from the queue, which may be a + pushback element. + </dd> + <dt>XMLEvent getEndDocument(events)</dt> + <dd> + <em>get</em> and discard elements from the queue + until an ENDDOCUMENT element is found and returned. + </dd> + <dt> XMLEvent expectEndDocument(events)</dt> + <dd> + If the next element on the queue is an ENDDOCUMENT event, + return it. Otherwise, push the element back and throw an + exception. Each of the <em>get</em> methods (except + <em>getEvent()</em> itself) has a corresponding + <em>expect</em> method. + </dd> + <dt>XMLEvent get/expectStartElement(events)</dt> + <dd> Return the next STARTELEMENT event from the queue.</dd> + <dt>XMLEvent get/expectStartElement(events, String + qName)</dt> + <dd> + Return the next STARTELEMENT with a QName matching + <em>qName</em>. + </dd> + <dt> + XMLEvent get/expectStartElement(events, int uriIndex, + String localName) + </dt> + <dd> + Return the next STARTELEMENT with a URI indicated by the + <em>uriIndex</em> and a local name matching <em>localName</em>. + </dd> + <dt> + XMLEvent get/expectStartElement(events, LinkedList list) + </dt> + <dd> + <em>list</em> contains instances of the nested class + <code>UriLocalName</code>, which hold a + <em>uriIndex</em> and a <em>localName</em>. Return + the next STARTELEMENT with a URI indicated by the + <em>uriIndex</em> and a local name matching + <em>localName</em> from any element of + <em>list</em>. + </dd> + <dt>XMLEvent get/expectEndElement(events)</dt> + <dd>Return the next ENDELEMENT.</dd> + <dt>XMLEvent get/expectEndElement(events, qName)</dt> + <dd>Return the next ENDELEMENT with QName + <em>qname</em>.</dd> + <dt>XMLEvent get/expectEndElement(events, uriIndex, localName)</dt> + <dd> + Return the next ENDELEMENT with a URI indicated by the + <em>uriIndex</em> and a local name matching + <em>localName</em>. + </dd> + <dt> + XMLEvent get/expectEndElement(events, XMLEvent event) + </dt> + <dd> + Return the next ENDELEMENT with a URI matching the + <em>uriIndex</em> and <em>localName</em> + matching those in the <em>event</em> argument. This + is intended as a quick way to find the ENDELEMENT matching + a previously returned STARTELEMENT. + </dd> + <dt>XMLEvent get/expectCharacters(events)</dt> + <dd>Return the next CHARACTERS event.</dd> + </dl> + </section> + <section> + <title>FOP modularisation</title> + <p> + This same principle can be extended to the other major + sub-systems of FOP processing. In each case, while it is + possible to hold a complete intermediate result in memory, + the memory costs of that approach are too high. The + sub-systems - xml parsing, FO tree construction, Area tree + construction and rendering - must run in parallel if the + footprint is to be kept manageable. By creating a series of + producer-consumer pairs linked by synchronized buffers, + logical isolation can be achieved while rates of processing + remain coupled. By introducing feedback loops conveying + information about the completion of processing of the + elements, sub-systems can dispose of or precis those + elements without having to be tightly coupled to downstream + processes.<br/><br/> + <strong>Figure 3</strong> + </p> + <figure src="processPlumbing.png" alt="FOP modularisation"/> + </section> + </section> + </body> +</document> + |
