зеркало из https://github.com/mozilla/pjs.git
565 строки
18 KiB
C++
565 строки
18 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* vim:cindent:ts=2:et:sw=2:
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*
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is Mozilla Communicator client code.
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*
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* The Initial Developer of the Original Code is
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* Netscape Communications Corporation.
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* Portions created by the Initial Developer are Copyright (C) 1998
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Steve Clark <buster@netscape.com>
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either of the GNU General Public License Version 2 or later (the "GPL"),
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* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK *****
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* This Original Code has been modified by IBM Corporation. Modifications made by IBM
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* described herein are Copyright (c) International Business Machines Corporation, 2000.
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* Modifications to Mozilla code or documentation identified per MPL Section 3.3
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*
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* Date Modified by Description of modification
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* 04/20/2000 IBM Corp. OS/2 VisualAge build.
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*/
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/* state and methods used while laying out a single line of a block frame */
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#ifndef nsLineLayout_h___
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#define nsLineLayout_h___
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#include "nsFrame.h"
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#include "nsDeque.h"
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#include "nsLineBox.h"
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#include "nsBlockReflowState.h"
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#include "plarena.h"
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class nsBlockFrame;
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class nsSpaceManager;
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class nsPlaceholderFrame;
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struct nsStyleText;
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class nsLineLayout {
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public:
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nsLineLayout(nsPresContext* aPresContext,
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nsSpaceManager* aSpaceManager,
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const nsHTMLReflowState* aOuterReflowState,
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const nsLineList::iterator* aLine);
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~nsLineLayout();
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void Init(nsBlockReflowState* aState, nscoord aMinLineHeight,
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PRInt32 aLineNumber) {
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mBlockRS = aState;
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mMinLineHeight = aMinLineHeight;
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mLineNumber = aLineNumber;
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}
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PRInt32 GetLineNumber() const {
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return mLineNumber;
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}
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void BeginLineReflow(nscoord aX, nscoord aY,
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nscoord aWidth, nscoord aHeight,
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PRBool aImpactedByFloats,
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PRBool aIsTopOfPage);
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void EndLineReflow();
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void UpdateBand(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight,
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PRBool aPlacedLeftFloat,
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nsIFrame* aFloatFrame);
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nsresult BeginSpan(nsIFrame* aFrame,
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const nsHTMLReflowState* aSpanReflowState,
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nscoord aLeftEdge,
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nscoord aRightEdge);
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// Returns the width of the span
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nscoord EndSpan(nsIFrame* aFrame);
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PRInt32 GetCurrentSpanCount() const;
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void SplitLineTo(PRInt32 aNewCount);
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PRBool IsZeroHeight();
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// Reflows the frame and returns the reflow status. aPushedFrame is PR_TRUE
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// if the frame is pushed to the next line because it doesn't fit
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nsresult ReflowFrame(nsIFrame* aFrame,
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nsReflowStatus& aReflowStatus,
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nsHTMLReflowMetrics* aMetrics,
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PRBool& aPushedFrame);
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nsresult AddBulletFrame(nsIFrame* aFrame,
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const nsHTMLReflowMetrics& aMetrics);
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void RemoveBulletFrame(nsIFrame* aFrame) {
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PushFrame(aFrame);
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}
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void VerticalAlignLine();
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PRBool TrimTrailingWhiteSpace();
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void HorizontalAlignFrames(nsRect& aLineBounds, PRBool aAllowJustify);
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/**
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* Handle all the relative positioning in the line, compute the
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* combined area (== overflow area) for the line, and handle view
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* sizing/positioning and the setting of NS_FRAME_OUTSIDE_CHILDREN.
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*/
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void RelativePositionFrames(nsRect& aCombinedArea);
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//----------------------------------------
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// Supporting methods and data for flags
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protected:
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#define LL_FIRSTLETTERSTYLEOK 0x00000008
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#define LL_ISTOPOFPAGE 0x00000010
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#define LL_UPDATEDBAND 0x00000020
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#define LL_IMPACTEDBYFLOATS 0x00000040
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#define LL_LASTFLOATWASLETTERFRAME 0x00000080
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#define LL_CANPLACEFLOAT 0x00000100
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#define LL_LINEENDSINBR 0x00000200
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#define LL_NEEDBACKUP 0x00000400
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#define LL_INFIRSTLINE 0x00000800
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#define LL_GOTLINEBOX 0x00001000
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#define LL_LASTFLAG LL_GOTLINEBOX
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PRUint16 mFlags;
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void SetFlag(PRUint32 aFlag, PRBool aValue)
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{
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NS_ASSERTION(aFlag<=LL_LASTFLAG, "bad flag");
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NS_ASSERTION(aValue==PR_FALSE || aValue==PR_TRUE, "bad value");
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if (aValue) { // set flag
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mFlags |= aFlag;
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}
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else { // unset flag
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mFlags &= ~aFlag;
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}
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}
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PRBool GetFlag(PRUint32 aFlag) const
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{
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NS_ASSERTION(aFlag<=LL_LASTFLAG, "bad flag");
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return !!(mFlags & aFlag);
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}
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public:
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// Support methods for word-wrapping during line reflow
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void SetTextJustificationWeights(PRInt32 aNumSpaces, PRInt32 aNumLetters) {
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mTextJustificationNumSpaces = aNumSpaces;
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mTextJustificationNumLetters = aNumLetters;
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}
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PRBool CanPlaceFloatNow() const;
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PRBool LineIsBreakable() const;
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PRBool GetLineEndsInBR() const
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{
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return GetFlag(LL_LINEENDSINBR);
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}
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void SetLineEndsInBR(PRBool aOn)
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{
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SetFlag(LL_LINEENDSINBR, aOn);
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}
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//----------------------------------------
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// Inform the line-layout about the presence of a floating frame
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// XXX get rid of this: use get-frame-type?
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PRBool InitFloat(nsPlaceholderFrame* aFrame, nsReflowStatus& aReflowStatus) {
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return mBlockRS->InitFloat(*this, aFrame, aReflowStatus);
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}
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PRBool AddFloat(nsPlaceholderFrame* aFrame, nsReflowStatus& aReflowStatus) {
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return mBlockRS->AddFloat(*this, aFrame, PR_FALSE, aReflowStatus);
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}
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void SetTrimmableWidth(nscoord aTrimmableWidth) {
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mTrimmableWidth = aTrimmableWidth;
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}
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//----------------------------------------
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PRBool GetFirstLetterStyleOK() const {
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return GetFlag(LL_FIRSTLETTERSTYLEOK);
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}
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void SetFirstLetterStyleOK(PRBool aSetting) {
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SetFlag(LL_FIRSTLETTERSTYLEOK, aSetting);
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}
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PRBool GetInFirstLine() const {
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return GetFlag(LL_INFIRSTLINE);
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}
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void SetInFirstLine(PRBool aSetting) {
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SetFlag(LL_INFIRSTLINE, aSetting);
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}
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//----------------------------------------
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nsPresContext* mPresContext;
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/**
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* Record where an optional break could have been placed. During line reflow,
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* frames containing optional break points (e.g., whitespace in text frames)
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* can call SetLastOptionalBreakPosition to record where a break could
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* have been made, but wasn't because we decided to place more content on
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* the line. For non-text frames, offset 0 means
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* before the content, offset PR_INT32_MAX means after the content.
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*
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* Currently this is used to handle cases where a single word comprises
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* multiple frames, and the first frame fits on the line but the whole word
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* doesn't. We look back to the last optional break position and
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* reflow the whole line again, forcing a break at that position. The last
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* optional break position could be in a text frame or else after a frame
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* that cannot be part of a text run, so those are the positions we record.
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*
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* @param aFits set to true if the break position is within the available width.
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*
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* @return PR_TRUE if we are actually reflowing with forced break position and we
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* should break here
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*/
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PRBool NotifyOptionalBreakPosition(nsIContent* aContent, PRInt32 aOffset,
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PRBool aFits) {
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NS_ASSERTION(!aFits || !GetFlag(LL_NEEDBACKUP),
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"Shouldn't be updating the break position with a break that fits after we've already flagged an overrun");
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// Remember the last break position that fits; if there was no break that fit,
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// just remember the first break
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if (aFits || !mLastOptionalBreakContent) {
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mLastOptionalBreakContent = aContent;
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mLastOptionalBreakContentOffset = aOffset;
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}
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return aContent && mForceBreakContent == aContent &&
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mForceBreakContentOffset == aOffset;
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}
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/**
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* Like NotifyOptionalBreakPosition, but here it's OK for LL_NEEDBACKUP
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* to be set, because the caller is merely pruning some saved break position(s)
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* that are actually not feasible.
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*/
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void RestoreSavedBreakPosition(nsIContent* aContent, PRInt32 aOffset) {
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mLastOptionalBreakContent = aContent;
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mLastOptionalBreakContentOffset = aOffset;
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}
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/**
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* Signal that no backing up will be required after all.
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*/
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void ClearOptionalBreakPosition() {
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SetFlag(LL_NEEDBACKUP, PR_FALSE);
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mLastOptionalBreakContent = nsnull;
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mLastOptionalBreakContentOffset = -1;
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}
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// Retrieve last set optional break position. When this returns null, no
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// optional break has been recorded (which means that the line can't break yet).
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nsIContent* GetLastOptionalBreakPosition(PRInt32* aOffset) {
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*aOffset = mLastOptionalBreakContentOffset;
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return mLastOptionalBreakContent;
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}
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/**
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* Check whether frames overflowed the available width and CanPlaceFrame
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* requested backing up to a saved break position.
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*/
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PRBool NeedsBackup() { return GetFlag(LL_NEEDBACKUP); }
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// Line layout may place too much content on a line, overflowing its available
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// width. When that happens, if SetLastOptionalBreakPosition has been
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// used to record an optional break that wasn't taken, we can reflow the line
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// again and force the break to happen at that point (i.e., backtracking
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// to the last choice point).
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// Record that we want to break at the given content+offset (which
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// should have been previously returned by GetLastOptionalBreakPosition
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// from another nsLineLayout).
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void ForceBreakAtPosition(nsIContent* aContent, PRInt32 aOffset) {
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mForceBreakContent = aContent;
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mForceBreakContentOffset = aOffset;
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}
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PRBool HaveForcedBreakPosition() { return mForceBreakContent != nsnull; }
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PRInt32 GetForcedBreakPosition(nsIContent* aContent) {
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return mForceBreakContent == aContent ? mForceBreakContentOffset : -1;
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}
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/**
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* This can't be null. It usually returns a block frame but may return
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* some other kind of frame when inline frames are reflowed in a non-block
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* context (e.g. MathML).
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*/
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nsIFrame* GetLineContainerFrame() const { return mBlockReflowState->frame; }
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const nsLineList::iterator* GetLine() const {
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return GetFlag(LL_GOTLINEBOX) ? &mLineBox : nsnull;
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}
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/**
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* Return the horizontal offset of the current reflowed-frame from the
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* edge of the line container. This is always positive, measured from
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* the right edge for RTL blocks and from the left edge for LTR blocks.
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*/
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nscoord GetCurrentFrameXDistanceFromBlock();
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protected:
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// This state is constant for a given block frame doing line layout
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nsSpaceManager* mSpaceManager;
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const nsStyleText* mStyleText; // for the block
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const nsHTMLReflowState* mBlockReflowState;
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nsIContent* mLastOptionalBreakContent;
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nsIContent* mForceBreakContent;
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PRInt32 mLastOptionalBreakContentOffset;
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PRInt32 mForceBreakContentOffset;
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// XXX remove this when landing bug 154892 (splitting absolute positioned frames)
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friend class nsInlineFrame;
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nsBlockReflowState* mBlockRS;/* XXX hack! */
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nscoord mMinLineHeight;
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PRUint8 mTextAlign;
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PRUint8 mPlacedFloats;
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// The amount of text indent that we applied to this line, needed for
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// max-element-size calculation.
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nscoord mTextIndent;
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// This state varies during the reflow of a line but is line
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// "global" state not span "local" state.
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PRInt32 mLineNumber;
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PRInt32 mTextJustificationNumSpaces;
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PRInt32 mTextJustificationNumLetters;
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nsLineList::iterator mLineBox;
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PRInt32 mTotalPlacedFrames;
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nscoord mTopEdge;
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nscoord mMaxTopBoxHeight;
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nscoord mMaxBottomBoxHeight;
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// Final computed line-height value after VerticalAlignFrames for
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// the block has been called.
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nscoord mFinalLineHeight;
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// Amount of trimmable whitespace width for the trailing text frame, if any
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nscoord mTrimmableWidth;
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// Per-frame data recorded by the line-layout reflow logic. This
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// state is the state needed to post-process the line after reflow
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// has completed (vertical alignment, horizontal alignment,
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// justification and relative positioning).
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struct PerSpanData;
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struct PerFrameData;
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friend struct PerSpanData;
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friend struct PerFrameData;
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struct PerFrameData {
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// link to next/prev frame in same span
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PerFrameData* mNext;
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PerFrameData* mPrev;
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// pointer to child span data if this is an inline container frame
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PerSpanData* mSpan;
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// The frame and its type
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nsIFrame* mFrame;
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nsCSSFrameType mFrameType;
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// From metrics
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nscoord mAscent;
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nsRect mBounds;
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nsRect mCombinedArea;
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// From reflow-state
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nsMargin mMargin;
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nsMargin mBorderPadding;
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nsMargin mOffsets;
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// state for text justification
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PRInt32 mJustificationNumSpaces;
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PRInt32 mJustificationNumLetters;
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// Other state we use
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PRUint8 mVerticalAlign;
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// PerFrameData flags
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#define PFD_RELATIVEPOS 0x00000001
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#define PFD_ISTEXTFRAME 0x00000002
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#define PFD_ISNONEMPTYTEXTFRAME 0x00000004
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#define PFD_ISNONWHITESPACETEXTFRAME 0x00000008
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#define PFD_ISLETTERFRAME 0x00000010
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#define PFD_RECOMPUTEOVERFLOW 0x00000020
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#define PFD_ISBULLET 0x00000040
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#define PFD_SKIPWHENTRIMMINGWHITESPACE 0x00000080
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#define PFD_LASTFLAG PFD_SKIPWHENTRIMMINGWHITESPACE
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PRUint8 mFlags;
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void SetFlag(PRUint32 aFlag, PRBool aValue)
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{
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NS_ASSERTION(aFlag<=PFD_LASTFLAG, "bad flag");
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NS_ASSERTION(aFlag<=PR_UINT8_MAX, "bad flag");
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NS_ASSERTION(aValue==PR_FALSE || aValue==PR_TRUE, "bad value");
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if (aValue) { // set flag
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mFlags |= aFlag;
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}
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else { // unset flag
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mFlags &= ~aFlag;
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}
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}
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PRBool GetFlag(PRUint32 aFlag) const
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{
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NS_ASSERTION(aFlag<=PFD_LASTFLAG, "bad flag");
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return !!(mFlags & aFlag);
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}
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PerFrameData* Last() {
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PerFrameData* pfd = this;
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while (pfd->mNext) {
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pfd = pfd->mNext;
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}
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return pfd;
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}
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};
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PerFrameData* mFrameFreeList;
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struct PerSpanData {
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union {
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PerSpanData* mParent;
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PerSpanData* mNextFreeSpan;
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};
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PerFrameData* mFrame;
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PerFrameData* mFirstFrame;
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PerFrameData* mLastFrame;
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const nsHTMLReflowState* mReflowState;
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PRPackedBool mNoWrap;
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PRUint8 mDirection;
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PRPackedBool mChangedFrameDirection;
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PRPackedBool mZeroEffectiveSpanBox;
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PRPackedBool mContainsFloat;
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nscoord mLeftEdge;
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nscoord mX;
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nscoord mRightEdge;
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nscoord mTopLeading, mBottomLeading;
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nscoord mLogicalHeight;
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nscoord mMinY, mMaxY;
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void AppendFrame(PerFrameData* pfd) {
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if (nsnull == mLastFrame) {
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mFirstFrame = pfd;
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}
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else {
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mLastFrame->mNext = pfd;
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pfd->mPrev = mLastFrame;
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}
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mLastFrame = pfd;
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}
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};
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PerSpanData* mSpanFreeList;
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PerSpanData* mRootSpan;
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PerSpanData* mCurrentSpan;
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PRInt32 mSpanDepth;
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#ifdef DEBUG
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PRInt32 mSpansAllocated, mSpansFreed;
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PRInt32 mFramesAllocated, mFramesFreed;
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#endif
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PLArenaPool mArena; // Per span and per frame data
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nsresult NewPerFrameData(PerFrameData** aResult);
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nsresult NewPerSpanData(PerSpanData** aResult);
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void FreeSpan(PerSpanData* psd);
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PRBool InBlockContext() const {
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return mSpanDepth == 0;
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}
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void PushFrame(nsIFrame* aFrame);
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void ApplyStartMargin(PerFrameData* pfd,
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nsHTMLReflowState& aReflowState);
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PRBool CanPlaceFrame(PerFrameData* pfd,
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const nsHTMLReflowState& aReflowState,
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PRBool aNotSafeToBreak,
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PRBool aFrameCanContinueTextRun,
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|
PRBool aCanRollBackBeforeFrame,
|
|
nsHTMLReflowMetrics& aMetrics,
|
|
nsReflowStatus& aStatus,
|
|
PRBool* aOptionalBreakAfterFits);
|
|
|
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void PlaceFrame(PerFrameData* pfd,
|
|
nsHTMLReflowMetrics& aMetrics);
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|
|
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void UpdateFrames();
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|
|
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void VerticalAlignFrames(PerSpanData* psd);
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|
|
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void PlaceTopBottomFrames(PerSpanData* psd,
|
|
nscoord aDistanceFromTop,
|
|
nscoord aLineHeight);
|
|
|
|
void RelativePositionFrames(PerSpanData* psd, nsRect& aCombinedArea);
|
|
|
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PRBool TrimTrailingWhiteSpaceIn(PerSpanData* psd, nscoord* aDeltaWidth);
|
|
|
|
void ComputeJustificationWeights(PerSpanData* psd, PRInt32* numSpaces, PRInt32* numLetters);
|
|
|
|
struct FrameJustificationState {
|
|
PRInt32 mTotalNumSpaces;
|
|
PRInt32 mTotalNumLetters;
|
|
nscoord mTotalWidthForSpaces;
|
|
nscoord mTotalWidthForLetters;
|
|
PRInt32 mNumSpacesProcessed;
|
|
PRInt32 mNumLettersProcessed;
|
|
nscoord mWidthForSpacesProcessed;
|
|
nscoord mWidthForLettersProcessed;
|
|
};
|
|
|
|
// Apply justification. The return value is the amount by which the width of
|
|
// the span corresponding to aPSD got increased due to justification.
|
|
nscoord ApplyFrameJustification(PerSpanData* aPSD,
|
|
FrameJustificationState* aState);
|
|
|
|
|
|
#ifdef DEBUG
|
|
void DumpPerSpanData(PerSpanData* psd, PRInt32 aIndent);
|
|
#endif
|
|
};
|
|
|
|
#endif /* nsLineLayout_h___ */
|