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<?xml version="1.0" encoding="utf-8"?>
<!--
* Copyright 2004-2005 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
-->
<!-- $Id$ -->
<!--
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"docbookx.dtd">
-->
<chapter>
<title>Phase 2: Building the Area tree</title>
<section>
<title>Initiating the layout process</title>
<para>In the <literal>PageSequence.endOfNode()</literal> method, the
<literal>AreaTreeHandler</literal> object
<literal>foEventHandler</literal>'s method
<literal>endPageSequence</literal> is called. This method constructs a
<literal>PageSequenceLayoutManager</literal> for the
<literal>PageSequence</literal> FO node, which manages all page-related
layout.</para>
<screen>
org.apache.fop.fo.pagination.PageSequence.endOfNode():
this.getFOEventHandler().getFOEventHandler().endPageSequence(this):
-> foTreeBuilder.getFOEventHandler().endPageSequence(this)
-> foEventHandler.endPageSequence(this) (type AreaTreeHandler):
</screen>
<para>This method creates a new
<literal>PageSequenceLayoutManager</literal> for the
<literal>PageSequence</literal> FO node. The pages in this page sequence
are completely layed out by the
<literal>PageSequenceLayoutManager</literal>, in its
<literal>activateLayout</literal> method. The first step in the layout
process is getting the page setup from the page masters. Then the FO tree
is processed.</para>
<screen>
[1] org.apache.fop.layoutmgr.PageSequenceLayoutManager.activateLayout (PageLayoutManager.java:211)
[2] org.apache.fop.fo.area.AreaTreeHandler.endPageSequence (AreaTreeHandler.java:242)
[3] org.apache.fop.fo.pagination.PageSequence.endOfNode (PageSequence.java:202)
[4] org.apache.fop.fo.FOTreeBuilder.endElement (FOTreeBuilder.java:292)
... parser stuff
[13] org.apache.xerces.parsers.AbstractSAXParser.parse (null)
[14] org.apache.xalan.transformer.TransformerIdentityImpl.transform (null)
[15] org.apache.fop.apps.InputHandler.render (InputHandler.java:120)
[16] org.apache.fop.apps.Fop.main (Fop.java:102)
</screen>
<screen>
main[1] dump pageSLM
pageSLM = {
areaTreeHandler= org.apache.fop.area.AreaTreeHandler (id=79)
areaTreeModel= org.apache.fop.area.RenderPagesModel (id=81)
bFinished= false
bFirstPage= false
bInited= false
childLMiter= org.apache.fop.layoutmgr.LMiter (id=85)
childLMs= java.util.ArrayList (id=89)
curBody= null
curChildLM= null
curFlow= null
curPage= null
currentSimplePageMaster= null
curSpan= null
curSpanColumns= 0
flowBPD= 0
flowIPD= 0
fobj= org.apache.fop.fo.pagination.PageSequence (id=12)
fobjIter= java.util.AbstractList$ListItr (id=90)
isFirstPage= true
markers= null
pageCount= 1
pageNumberGenerator= null
pageNumberString= null
parentLM= null
staticContentLMs= java.util.HashMap (id=93)
}
</screen>
<para>The above calling sequence contains one configuration
point. FOP's area tree building process can be modified by
registering a different LayoutManagerMaker with the Area tree
handler. The LayoutManagerMaker controls the creation of Layout
Managers.
<warning>
<simpara>TO BE EXPANDED</simpara>
</warning></para>
</section>
<section>
<title>Creating the page and body areas</title>
<section>
<title>Overview</title>
<para>Create the layout (<literal>activateLayout</literal>) <itemizedlist spacing="compact">
<listitem>
<para>First create a new Page Viewport
(<literal>makeNewPage</literal>). <itemizedlist spacing="compact">
<listitem>
<para>First finish the current page
(<literal>finishPage</literal>).</para>
</listitem>
<listitem>
<para>Then create the new page viewport
(<literal>createPage</literal>). <itemizedlist spacing="compact">
<listitem>
<para>First get the page master
(<literal>getSimplePageMasterToUse</literal>,
<literal>pageSequence.getPageSequenceMaster</literal> or
<literal>pageSequence.getSimplePageMaster</literal>).</para>
</listitem>
<listitem>
<para>Then get the body
(<literal>currentSimplePageMaster.getRegion</literal>, from
<literal>currentSimplePageMaster</literal>'s
<literal>regions</literal> map).</para>
</listitem>
<listitem>
<para>Then create the page viewport
(<literal>createPageAreas(currentSimplePageMaster)</literal>).
<itemizedlist spacing="compact">
<listitem>
<para>From the properties of the page
master create the page reference rectangle, a new page, a new
FODimension object, and a CTM object.</para>
</listitem>
<listitem>
<para>For each region in the page master
(in our example we only have a body): <itemizedlist spacing="compact">
<listitem>
<para>make a region viewport
(<literal>makeRegionViewport</literal>), which involves calculating
the position of the region on the page, using the FODimension and CTM
objects.
</para>
</listitem>
<listitem>
<para>make the reference area
(<literal>makeRegionBodyReferenceArea</literal>,
<literal>makeRegionReferenceArea</literal>).</para>
</listitem>
</itemizedlist></para>
</listitem>
</itemizedlist></para>
</listitem>
</itemizedlist></para>
</listitem>
</itemizedlist></para>
</listitem>
</itemizedlist></para>
<para>At this point the page viewport and its region viewports
have been laid out.</para>
<para> <itemizedlist spacing="compact">
<listitem>
<simpara>Then create the body's main reference area
(<literal>createBodyMainReferenceArea</literal>).</simpara>
</listitem>
<listitem>
<simpara>Then create a Span
(<literal>createSpan</literal>).</simpara>
</listitem>
<listitem>
<simpara>And get the flowIPD
(curFlow.<literal>getIPD</literal>()).</simpara>
</listitem>
</itemizedlist></para>
<para>At this point the body has a single span area with a
single flow area without children.
</para>
</section>
<section>
<title>Detailed view</title>
<para>The call stack when creating the region viewports:
<screen>
[1] org.apache.fop.layoutmgr.PageLayoutManager.makeRegionViewport (PageLayoutManager.java:832)
[2] org.apache.fop.layoutmgr.PageLayoutManager.createPageAreas (PageLayoutManager.java:805)
[3] org.apache.fop.layoutmgr.PageLayoutManager.createPage (PageLayoutManager.java:748)
[4] org.apache.fop.layoutmgr.PageLayoutManager.makeNewPage (PageLayoutManager.java:467)
[5] org.apache.fop.layoutmgr.PageLayoutManager.activateLayout (PageLayoutManager.java:220)
</screen>
</para>
<para>At the end of <literal>createPageAreas</literal> the following
properties of the page have been established:</para>
<para>The page reference rectangle:
<screen>
pageRefRect = {
x: 56692
y: 56692
width: 481891
height: 728505
serialVersionUID: -4345857070255674764
}
</screen>
</para>
<para>The page reference area:
<screen>
page = {
regionBefore: null
regionStart: null
regionBody: instance of org.apache.fop.area.RegionViewport(id=1279)
regionEnd: null
regionAfter: null
unresolved: null
}
</screen>
<screen>
page.regionBody = {
region: instance of org.apache.fop.area.BodyRegion(id=1280)
viewArea: instance of java.awt.Rectangle(id=1281)
clip: false
org.apache.fop.area.Area.areaClass: 0
org.apache.fop.area.Area.ipd: 0
org.apache.fop.area.Area.props: null
}
</screen>
<screen>
page.regionBody.region = {
beforeFloat: null
mainReference: null
footnote: null
columnGap: 18000
columnCount: 1
refIPD: 0
org.apache.fop.area.RegionReference.regionClass: 2
org.apache.fop.area.RegionReference.ctm: instance of org.apache.fop.area.CTM(id=1282)
org.apache.fop.area.RegionReference.blocks: instance of java.util.ArrayList(id=1283)
org.apache.fop.area.Area.areaClass: 0
org.apache.fop.area.Area.ipd: 0
org.apache.fop.area.Area.props: null
}
</screen>
<screen>
page.regionBody.viewArea = {
x: 56692
y: 56692
width: 481891
height: 728505
serialVersionUID: -4345857070255674764
}
</screen>
</para>
<para>The <literal>PageViewport</literal> is returned:</para>
<screen>
curPage = {
page: instance of org.apache.fop.area.Page(id=1261)
viewArea: instance of java.awt.Rectangle(id=1289)
clip: false
pageNumber: null
idReferences: null
unresolved: null
pendingResolved: null
markerFirstStart: null
markerLastStart: null
markerFirstAny: null
markerLastEnd: null
markerLastAny: null
}
</screen>
<para>When <literal>makeNewPage</literal> returns, the Page
LayoutManager has a Page Viewport and a Body Region object. The layout
dimensions have been calculated:</para>
<screen>
this = {
pageNumberGenerator: instance of org.apache.fop.fo.pagination.PageNumberGenerator(id=1003)
pageCount: 1
pageNumberString: "1"
isFirstPage: false
bFirstPage: false
curPage: instance of org.apache.fop.area.PageViewport(id=1288)
curBody: instance of org.apache.fop.area.BodyRegion(id=1280)
curSpan: null
curSpanColumns: 0
curFlow: null
flowBPD: 728505
flowIPD: 0
areaTree: instance of org.apache.fop.area.AreaTree(id=1005)
pageSequence: instance of org.apache.fop.fo.pagination.PageSequence(id=1006)
currentSimplePageMaster: instance of org.apache.fop.fo.pagination.SimplePageMaster(id=1007)
staticContentLMs: instance of java.util.HashMap(id=1008)
lmls: instance of org.apache.fop.layoutmgr.LayoutManagerLS(id=1009)
org.apache.fop.layoutmgr.AbstractLayoutManager.userAgent: instance of org.apache.fop.apps.FOUserAgent(id=1010)
org.apache.fop.layoutmgr.AbstractLayoutManager.parentLM: null
org.apache.fop.layoutmgr.AbstractLayoutManager.fobj: instance of org.apache.fop.fo.pagination.PageSequence(id=1006)
org.apache.fop.layoutmgr.AbstractLayoutManager.foID: null
org.apache.fop.layoutmgr.AbstractLayoutManager.markers: null
org.apache.fop.layoutmgr.AbstractLayoutManager.bFinished: false
org.apache.fop.layoutmgr.AbstractLayoutManager.curChildLM: null
org.apache.fop.layoutmgr.AbstractLayoutManager.childLMiter: instance of org.apache.fop.layoutmgr.LMiter(id=1011)
org.apache.fop.layoutmgr.AbstractLayoutManager.bInited: false
}
</screen>
<para>The method <literal>createBodyMainReferenceArea()</literal> adds
a <literal>MainReferenceArea</literal> to the body region:</para>
<screen>
curBody = {
beforeFloat: null
mainReference: instance of org.apache.fop.area.MainReference(id=1293)
footnote: null
columnGap: 18000
columnCount: 1
refIPD: 0
org.apache.fop.area.RegionReference.regionClass: 2
org.apache.fop.area.RegionReference.ctm: instance of org.apache.fop.area.CTM(id=1282)
org.apache.fop.area.RegionReference.blocks: instance of java.util.ArrayList(id=1283)
org.apache.fop.area.Area.areaClass: 0
org.apache.fop.area.Area.ipd: 0
org.apache.fop.area.Area.props: null
}
</screen>
<screen>
curBody.mainReference = {
spanAreas: instance of java.util.ArrayList(id=1294)
columnGap: 0
width: 0
org.apache.fop.area.Area.areaClass: 0
org.apache.fop.area.Area.ipd: 0
org.apache.fop.area.Area.props: null
}
</screen>
<screen>
curBody.mainReference.spanAreas = "[]"
</screen>
<para>After <literal>createSpan(1)</literal>:</para>
<screen>
curBody.mainReference.spanAreas = "[org.apache.fop.area.Span@1581e80]"
</screen>
<screen>
curBody.mainReference.spanAreas.get(0) = {
flowAreas: instance of java.util.ArrayList(id=1299)
height: 0
org.apache.fop.area.Area.areaClass: 0
org.apache.fop.area.Area.ipd: 481891
org.apache.fop.area.Area.props: null
}
</screen>
</section>
</section>
</chapter>
<!-- Local Variables: -->
<!-- current-language-environment: UTF-8 -->
<!-- coding: utf-8 -->
<!-- default-input-method: TeX -->
<!-- End: -->
|
