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/*
* $Id$
* Copyright (C) 2001 The Apache Software Foundation. All rights reserved.
* For details on use and redistribution please refer to the
* LICENSE file included with these sources.
*/
package org.apache.fop.layoutmgr;
import org.apache.fop.apps.FOPException;
import org.apache.fop.fo.FObj;
import org.apache.fop.fo.properties.Constants;
import org.apache.fop.area.*;
import java.util.ArrayList;
import java.util.List;
/**
* LayoutManager for an fo:flow object.
* Its parent LM is the PageLayoutManager.
* This LM is responsible for getting columns of the appropriate size
* and filling them with block-level areas generated by its children.
*/
public class FlowLayoutManager extends BlockStackingLayoutManager {
ArrayList blockBreaks = new ArrayList();
/** Array of areas currently being filled stored by area class */
private BlockParent[] currentAreas = new BlockParent[Area.CLASS_MAX];
/**
* This is the top level layout manager.
* It is created by the PageSequence FO.
*/
public FlowLayoutManager(FObj fobj) {
super(fobj);
}
public BreakPoss getNextBreakPoss(LayoutContext context,
Position prevLineBP) {
BPLayoutManager curLM ; // currently active LM
MinOptMax stackSize = new MinOptMax();
while ((curLM = getChildLM()) != null) {
// Make break positions and return page break
// Set up a LayoutContext
MinOptMax bpd = context.getStackLimit();
BreakPoss bp;
LayoutContext childLC = new LayoutContext(0);
boolean breakPage = false;
childLC.setStackLimit(MinOptMax.subtract(bpd, stackSize));
childLC.setRefIPD(context.getRefIPD());
if (!curLM.isFinished()) {
if ((bp = curLM.getNextBreakPoss(childLC, null)) != null) {
stackSize.add(bp.getStackingSize());
blockBreaks.add(bp);
// set stackLimit for remaining space
childLC.setStackLimit(MinOptMax.subtract(bpd, stackSize));
if(bp.isForcedBreak()) {
breakPage = true;
break;
}
}
}
// check the stack bpd and if greater than available
// height then go to the last best break and return
// break position
if(stackSize.min > context.getStackLimit().opt) {
breakPage = true;
}
if(breakPage) {
return new BreakPoss(
new LeafPosition(this, blockBreaks.size() - 1));
}
}
setFinished(true);
if(blockBreaks.size() > 0) {
return new BreakPoss(
new LeafPosition(this, blockBreaks.size() - 1));
}
return null;
}
public void addAreas(PositionIterator parentIter, LayoutContext layoutContext) {
BPLayoutManager childLM ;
int iStartPos = 0;
LayoutContext lc = new LayoutContext(0);
while (parentIter.hasNext()) {
LeafPosition lfp = (LeafPosition) parentIter.next();
// Add the block areas to Area
PositionIterator breakPosIter =
new BreakPossPosIter(blockBreaks, iStartPos,
lfp.getLeafPos() + 1);
iStartPos = lfp.getLeafPos() + 1;
while ((childLM = breakPosIter.getNextChildLM()) != null) {
childLM.addAreas(breakPosIter, lc);
}
}
flush();
// clear the breaks for the page to start for the next page
blockBreaks.clear();
}
/**
* Add child area to a the correct container, depending on its
* area class. A Flow can fill at most one area container of any class
* at any one time. The actual work is done by BlockStackingLM.
*/
public boolean addChild(Area childArea) {
return addChildToArea(childArea,
this.currentAreas[childArea.getAreaClass()]);
}
public Area getParentArea(Area childArea) {
// Get an area from the Page
BlockParent parentArea =
(BlockParent) parentLM.getParentArea(childArea);
this.currentAreas[parentArea.getAreaClass()] = parentArea;
setCurrentArea(parentArea);
return parentArea;
}
}
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