<body>
<section>
<title>Properties$AbsolutePosition</title>
- <figure src="AbsolutePosition.png" alt="AbsolutePosition diagram"/>
+ <figure src="images/design/alt.design/AbsolutePosition.png" alt="AbsolutePosition diagram"/>
</section>
</body>
<body>
<section>
<title>Properties$BorderCommonStyle</title>
- <figure src="BorderCommonStyle.png" alt="BorderCommonStyle diagram"/>
+ <figure src="images/design/alt.design/BorderCommonStyle.png" alt="BorderCommonStyle diagram"/>
</section>
</body>
</document>
<document>
<header>
<title>..fo.PropNames diagram</title>
+ <authors>
<person id="pbw" name="Peter B. West"
email="pbwest@powerup.com.au"/>
</authors>
<body>
<section>
<title>PropNames.class</title>
- <figure src="PropNames.png" alt="PropNames.class diagram"/>
+ <figure src="images/design/alt.design/PropNames.png" alt="PropNames.class diagram"/>
</section>
</body>
</document>
<body>
<section>
<title>Properties.class</title>
- <figure src="Properties.png" alt="Properties.class diagram"/>
+ <figure src="images/design/alt.design/Properties.png" alt="Properties.class diagram"/>
</section>
</body>
</document>
<body>
<section>
<title>PropertyConsts.class</title>
- <figure src="PropertyConsts.png" alt="PropertyConsts.class diagram"/>
+ <figure src="images/design/alt.design/PropertyConsts.png" alt="PropertyConsts.class diagram"/>
</section>
</body>
</document>
<body>
<section>
<title>Properties$VerticalAlign</title>
- <figure src="VerticalAlign.png" alt="VerticalAlign diagram"/>
+ <figure src="images/design/alt.design/VerticalAlign.png" alt="VerticalAlign diagram"/>
</section>
</body>
</document>
--- /dev/null
+<?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>
+ <ul>
+ <!-- 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>
+ </ul>
+ <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>
+
+++ /dev/null
-<?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>
-
<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="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"/>
static data and methods have been split tentatively into
three:
</p>
- <figure src="PropertyStaticsOverview.png" alt="Top level
+ <figure src="images/design/alt.design/PropertyStaticsOverview.png" alt="Top level
property classes"/>
<dl>
<dt><link href="PropNames.html">PropNames</link></dt>
</section>
<p>
<strong>Previous:</strong> <link href=
- "alt.properties.html" >alt.properties</link>
+ "alt-properties.html" >alt.properties</link>
</p>
<p>
<strong>Next:</strong> <link href=
left off.<br/><br/>
<strong>Figure 1</strong>
</p>
- <figure src="coroutines.png" alt="Co-routine diagram"/>
+ <figure src="images/design/alt.design/coroutines.png" alt="Co-routine diagram"/>
<p>
For example, think of a page-production method working on a
complex page-sequence-master.
<title>Footnotes and galleys</title>
<p>
In the structure described in the <link href=
- "../galleys.html" >introduction to FOP galleys</link>,
+ "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
<p>
When footnotes are introduced, the communication between
galleys and layout manager, as mentioned <link href=
- "../galleys.html#pre-processing" >above</link>, would be
+ "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
</note>
<p>
This note assumes a galley, as discussed <link href=
- "../galleys.html" >elsewhere</link>, flowing text with
+ "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
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
+ <figure src="images/design/alt.design/initial-column-values.png" alt="Columns before
first footnote"/>
</section>
<section>
<strong>Figure 2</strong> Adding a line area with first
footnote.
</p>
- <figure src="line-area-5.png"
+ <figure src="images/design/alt.design/line-area-5.png"
alt="Columns after adding first footnote"/>
<p>
Columns are balanced dynamically in the galley preliminary
<strong>Figure 3</strong> Adding a line area with next
footnote.
</p>
- <figure src="line-area-6.png"
+ <figure src="images/design/alt.design/line-area-6.png"
alt="Columns after adding next footnote"/>
</section>
<section>
"../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
+ "../areas.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
<br/><br/>
<strong>Figure 1</strong>
</p>
- <figure src="galley-preprocessing.png" alt="Galley
+ <figure src="images/design/alt.design/galley-preprocessing.png" alt="Galley
pre-processing diagram"/>
<p>
Once this pre-processing has been achieved, it is
<strong>Figure 1</strong>
</p>
<anchor id="Figure1"/>
- <figure src="block-stacking.png" alt="Simple block-stacking
+ <figure src="images/design/alt.design/block-stacking.png" alt="Simple block-stacking
diagram"/>
<p>
The three basic links are:
<body>
<section>
<title>fo.Properties and the nested properties classes</title>
- <figure src="PropertyClasses.png" alt="Nested property and
+ <figure src="images/design/alt.design/PropertyClasses.png" alt="Nested property and
top-level classes"/>
<section>
<title>Nested property classes</title>
<link href="#Figure1">Figure 1</link>.)
</p>
<p><strong>Figure 1</strong></p><anchor id="Figure1"/>
- <figure src="block-stacking-constraints.png"
+ <figure src="images/design/alt.design/block-stacking-constraints.png"
alt="block-stacking-constraints.png"/>
<note>
Figure 1 assumes a block-progression-direction of top to
</p>
<p><strong>Figure 2</strong></p>
<anchor id="Figure2"/>
- <figure src="block-stacking-keeps.png"
+ <figure src="images/design/alt.design/block-stacking-keeps.png"
alt="block-stacking-keeps.png"/>
</section>
<section>
value to a "reasonable" value based on the font size of
the element.
</p>
- </s3>
+ </section>
<p>
... When an element contains text that is rendered in more
than one font, <strong>user agents</strong> should determine
</section>
<section>
<title>7.26.5 "border-separation"</title>
- <s3 title="<length-bp-ip-direction>">
+ <section>
+ <title><length-bp-ip-direction></title>
<p>
... Rows, columns, row groups, and column groups cannot
have borders (i.e., <strong>user agents</strong> must
callback must complete before the next is called.<br/><br/>
<strong>Figure 1</strong>
</p>
- <figure src="SAXParsing.png" alt="SAX parsing schematic"/>
+ <figure src="images/design/alt.design/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
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"/>
+ <figure src="images/design/alt.design/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
processes.<br/><br/>
<strong>Figure 3</strong>
</p>
- <figure src="processPlumbing.png" alt="FOP modularisation"/>
+ <figure src="images/design/alt.design/processPlumbing.png" alt="FOP modularisation"/>
</section>
</section>
</body>
projects / xmlgraphics-fop.git / commitdiff
