gecko/layout/generic/nsBlockReflowState.h
2012-07-30 17:20:58 +03:00

287 lines
10 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* state used in reflow of block frames */
#ifndef nsBlockReflowState_h__
#define nsBlockReflowState_h__
#include "nsFloatManager.h"
#include "nsLineBox.h"
#include "nsFrameList.h"
#include "nsBlockFrame.h"
// block reflow state flags
#define BRS_UNCONSTRAINEDHEIGHT 0x00000001
#define BRS_ISTOPMARGINROOT 0x00000002 // Is this frame a root for top/bottom margin collapsing?
#define BRS_ISBOTTOMMARGINROOT 0x00000004
#define BRS_APPLYTOPMARGIN 0x00000008 // See ShouldApplyTopMargin
#define BRS_ISFIRSTINFLOW 0x00000010
// Set when mLineAdjacentToTop is valid
#define BRS_HAVELINEADJACENTTOTOP 0x00000020
// Set when the block has the equivalent of NS_BLOCK_FLOAT_MGR
#define BRS_FLOAT_MGR 0x00000040
// Set when nsLineLayout::LineIsEmpty was true at the end of reflowing
// the current line
#define BRS_LINE_LAYOUT_EMPTY 0x00000080
#define BRS_ISOVERFLOWCONTAINER 0x00000100
// Our mPushedFloats list is stored on the blocks' proptable
#define BRS_PROPTABLE_FLOATCLIST 0x00000200
#define BRS_LASTFLAG BRS_PROPTABLE_FLOATCLIST
class nsBlockReflowState {
public:
nsBlockReflowState(const nsHTMLReflowState& aReflowState,
nsPresContext* aPresContext,
nsBlockFrame* aFrame,
const nsHTMLReflowMetrics& aMetrics,
bool aTopMarginRoot, bool aBottomMarginRoot,
bool aBlockNeedsFloatManager);
/**
* Get the available reflow space (the area not occupied by floats)
* for the current y coordinate. The available space is relative to
* our coordinate system, which is the content box, with (0, 0) in the
* upper left.
*
* Returns whether there are floats present at the given vertical
* coordinate and within the width of the content rect.
*/
nsFlowAreaRect GetFloatAvailableSpace() const
{ return GetFloatAvailableSpace(mY); }
nsFlowAreaRect GetFloatAvailableSpace(nscoord aY) const
{ return GetFloatAvailableSpaceWithState(aY, nullptr); }
nsFlowAreaRect
GetFloatAvailableSpaceWithState(nscoord aY,
nsFloatManager::SavedState *aState) const;
nsFlowAreaRect
GetFloatAvailableSpaceForHeight(nscoord aY, nscoord aHeight,
nsFloatManager::SavedState *aState) const;
/*
* The following functions all return true if they were able to
* place the float, false if the float did not fit in available
* space.
* aLineLayout is null when we are reflowing pushed floats (because
* they are not associated with a line box).
*/
bool AddFloat(nsLineLayout* aLineLayout,
nsIFrame* aFloat,
nscoord aAvailableWidth);
private:
bool CanPlaceFloat(nscoord aFloatWidth,
const nsFlowAreaRect& aFloatAvailableSpace);
public:
bool FlowAndPlaceFloat(nsIFrame* aFloat);
private:
void PushFloatPastBreak(nsIFrame* aFloat);
public:
void PlaceBelowCurrentLineFloats(nsFloatCacheFreeList& aFloats,
nsLineBox* aLine);
// Returns the first coordinate >= aY that clears the
// floats indicated by aBreakType and has enough width between floats
// (or no floats remaining) to accomodate aReplacedBlock.
nscoord ClearFloats(nscoord aY, PRUint8 aBreakType,
nsIFrame *aReplacedBlock = nullptr,
PRUint32 aFlags = 0);
bool IsAdjacentWithTop() const {
return mY ==
((mFlags & BRS_ISFIRSTINFLOW) ? mReflowState.mComputedBorderPadding.top : 0);
}
/**
* Adjusts the border/padding to return 0 for the top if
* we are not the first in flow.
*/
nsMargin BorderPadding() const {
nsMargin result = mReflowState.mComputedBorderPadding;
if (!(mFlags & BRS_ISFIRSTINFLOW)) {
result.top = 0;
if (mFlags & BRS_ISOVERFLOWCONTAINER) {
result.bottom = 0;
}
}
return result;
}
// XXX maybe we should do the same adjustment for continuations here
const nsMargin& Margin() const {
return mReflowState.mComputedMargin;
}
// Reconstruct the previous bottom margin that goes above |aLine|.
void ReconstructMarginAbove(nsLineList::iterator aLine);
// Caller must have called GetAvailableSpace for the correct position
// (which need not be the current mY).
void ComputeReplacedBlockOffsetsForFloats(nsIFrame* aFrame,
const nsRect& aFloatAvailableSpace,
nscoord& aLeftResult,
nscoord& aRightResult);
// Caller must have called GetAvailableSpace for the current mY
void ComputeBlockAvailSpace(nsIFrame* aFrame,
const nsStyleDisplay* aDisplay,
const nsFlowAreaRect& aFloatAvailableSpace,
bool aBlockAvoidsFloats,
nsRect& aResult);
protected:
void RecoverFloats(nsLineList::iterator aLine, nscoord aDeltaY);
public:
void RecoverStateFrom(nsLineList::iterator aLine, nscoord aDeltaY);
void AdvanceToNextLine() {
if (GetFlag(BRS_LINE_LAYOUT_EMPTY)) {
SetFlag(BRS_LINE_LAYOUT_EMPTY, false);
} else {
mLineNumber++;
}
}
//----------------------------------------
// This state is the "global" state computed once for the reflow of
// the block.
// The block frame that is using this object
nsBlockFrame* mBlock;
nsPresContext* mPresContext;
const nsHTMLReflowState& mReflowState;
nsFloatManager* mFloatManager;
// The coordinates within the float manager where the block is being
// placed <b>after</b> taking into account the blocks border and
// padding. This, therefore, represents the inner "content area" (in
// spacemanager coordinates) where child frames will be placed,
// including child blocks and floats.
nscoord mFloatManagerX, mFloatManagerY;
// XXX get rid of this
nsReflowStatus mReflowStatus;
// The float manager state as it was before the contents of this
// block. This is needed for positioning bullets, since we only want
// to move the bullet to flow around floats that were before this
// block, not floats inside of it.
nsFloatManager::SavedState mFloatManagerStateBefore;
nscoord mBottomEdge;
// The content area to reflow child frames within. This is within
// this frame's coordinate system, which means mContentArea.x ==
// BorderPadding().left and mContentArea.y == BorderPadding().top.
// The height may be NS_UNCONSTRAINEDSIZE, which indicates that there
// is no page/column boundary below (the common case).
// mContentArea.YMost() should only be called after checking that
// mContentArea.height is not NS_UNCONSTRAINEDSIZE; otherwise
// coordinate overflow may occur.
nsRect mContentArea;
// Continuation out-of-flow float frames that need to move to our
// next in flow are placed here during reflow. It's a pointer to
// a frame list stored in the block's property table.
nsFrameList *mPushedFloats;
// This method makes sure pushed floats are accessible to
// StealFrame. Call it before adding any frames to mPushedFloats.
void SetupPushedFloatList();
// Use this method to append to mPushedFloats.
void AppendPushedFloat(nsIFrame* aFloatCont) {
SetupPushedFloatList();
aFloatCont->AddStateBits(NS_FRAME_IS_PUSHED_FLOAT);
mPushedFloats->AppendFrame(mBlock, aFloatCont);
}
// Track child overflow continuations.
nsOverflowContinuationTracker* mOverflowTracker;
//----------------------------------------
// This state is "running" state updated by the reflow of each line
// in the block. This same state is "recovered" when a line is not
// dirty and is passed over during incremental reflow.
// The current line being reflowed
// If it is mBlock->end_lines(), then it is invalid.
nsLineList::iterator mCurrentLine;
// When BRS_HAVELINEADJACENTTOTOP is set, this refers to a line
// which we know is adjacent to the top of the block (in other words,
// all lines before it are empty and do not have clearance. This line is
// always before the current line.
nsLineList::iterator mLineAdjacentToTop;
// The current Y coordinate in the block
nscoord mY;
// The overflow areas of all floats placed so far
nsOverflowAreas mFloatOverflowAreas;
nsFloatCacheFreeList mFloatCacheFreeList;
// Previous child. This is used when pulling up a frame to update
// the sibling list.
nsIFrame* mPrevChild;
// The previous child frames collapsed bottom margin value.
nsCollapsingMargin mPrevBottomMargin;
// The current next-in-flow for the block. When lines are pulled
// from a next-in-flow, this is used to know which next-in-flow to
// pull from. When a next-in-flow is emptied of lines, we advance
// this to the next next-in-flow.
nsBlockFrame* mNextInFlow;
//----------------------------------------
// Temporary line-reflow state. This state is used during the reflow
// of a given line, but doesn't have meaning before or after.
// The list of floats that are "current-line" floats. These are
// added to the line after the line has been reflowed, to keep the
// list fiddling from being N^2.
nsFloatCacheFreeList mCurrentLineFloats;
// The list of floats which are "below current-line"
// floats. These are reflowed/placed after the line is reflowed
// and placed. Again, this is done to keep the list fiddling from
// being N^2.
nsFloatCacheFreeList mBelowCurrentLineFloats;
nscoord mMinLineHeight;
PRInt32 mLineNumber;
PRInt16 mFlags;
PRUint8 mFloatBreakType;
void SetFlag(PRUint32 aFlag, bool aValue)
{
NS_ASSERTION(aFlag<=BRS_LASTFLAG, "bad flag");
NS_ASSERTION(aValue==false || aValue==true, "bad value");
if (aValue) { // set flag
mFlags |= aFlag;
}
else { // unset flag
mFlags &= ~aFlag;
}
}
bool GetFlag(PRUint32 aFlag) const
{
NS_ASSERTION(aFlag<=BRS_LASTFLAG, "bad flag");
return !!(mFlags & aFlag);
}
};
#endif // nsBlockReflowState_h__