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gecko/layout/base/nsBidiPresUtils.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is
* IBM Corporation.
* Portions created by the Initial Developer are Copyright (C) 2000
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* IBM Corporation
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifdef IBMBIDI
#ifndef nsBidiPresUtils_h___
#define nsBidiPresUtils_h___
#include "nsTArray.h"
#include "nsIFrame.h"
#include "nsBidi.h"
#include "nsBidiUtils.h"
#include "nsCOMPtr.h"
#include "nsDataHashtable.h"
#include "nsBlockFrame.h"
#include "nsTHashtable.h"
#ifdef DrawText
#undef DrawText
#endif
/**
* A structure representing some continuation state for each frame on the line,
* used to determine the first and the last continuation frame for each
* continuation chain on the line.
*/
struct nsFrameContinuationState : public nsVoidPtrHashKey
{
nsFrameContinuationState(const void *aFrame) : nsVoidPtrHashKey(aFrame) {}
/**
* The first visual frame in the continuation chain containing this frame, or
* nsnull if this frame is the first visual frame in the chain.
*/
nsIFrame* mFirstVisualFrame;
/**
* The number of frames in the continuation chain containing this frame, if
* this frame is the first visual frame of the chain, or 0 otherwise.
*/
PRUint32 mFrameCount;
/**
* TRUE if this frame is the first visual frame of its continuation chain on
* this line and the chain has some frames on the previous lines.
*/
PRPackedBool mHasContOnPrevLines;
/**
* TRUE if this frame is the first visual frame of its continuation chain on
* this line and the chain has some frames left for next lines.
*/
PRPackedBool mHasContOnNextLines;
};
/*
* Following type is used to pass needed hashtable to reordering methods
*/
typedef nsTHashtable<nsFrameContinuationState> nsContinuationStates;
/**
* A structure representing a logical position which should be resolved
* into its visual position during BiDi processing.
*/
struct nsBidiPositionResolve
{
// [in] Logical index within string.
PRInt32 logicalIndex;
// [out] Visual index within string.
// If the logical position was not found, set to kNotFound.
PRInt32 visualIndex;
// [out] Visual position of the character, from the left (on the X axis), in twips.
// Eessentially, this is the X position (relative to the rendering context) where the text was drawn + the font metric of the visual string to the left of the given logical position.
// If the logical position was not found, set to kNotFound.
PRInt32 visualLeftTwips;
// [out] Visual width of the character, in twips.
// If the logical position was not found, set to kNotFound.
PRInt32 visualWidth;
};
class nsBidiPresUtils {
public:
nsBidiPresUtils();
~nsBidiPresUtils();
PRBool IsSuccessful(void) const;
/**
* Interface for the processor used by ProcessText. Used by process text to
* collect information about the width of subruns and to notify where each
* subrun should be rendered.
*/
class BidiProcessor {
public:
virtual ~BidiProcessor() { }
/**
* Sets the current text with the given length and the given direction.
*
* @remark The reason that the function gives a string instead of an index
* is that ProcessText copies and modifies the string passed to it, so
* passing an index would be impossible.
*
* @param aText The string of text.
* @param aLength The length of the string of text.
* @param aDirection The direction of the text. The string will never have
* mixed direction.
*/
virtual void SetText(const PRUnichar* aText,
PRInt32 aLength,
nsBidiDirection aDirection) = 0;
/**
* Returns the measured width of the text given in SetText. If SetText was
* not called with valid parameters, the result of this call is undefined.
* This call is guaranteed to only be called once between SetText calls.
* Will be invoked before DrawText.
*/
virtual nscoord GetWidth() = 0;
/**
* Draws the text given in SetText to a rendering context. If SetText was
* not called with valid parameters, the result of this call is undefined.
* This call is guaranteed to only be called once between SetText calls.
*
* @param aXOffset The offset of the left side of the substring to be drawn
* from the beginning of the overall string passed to ProcessText.
* @param aWidth The width returned by GetWidth.
*/
virtual void DrawText(nscoord aXOffset,
nscoord aWidth) = 0;
};
/**
* Make Bidi engine calculate the embedding levels of the frames that are
* descendants of a given block frame.
*
* @param aBlockFrame The block frame
*
* @lina 06/18/2000
*/
nsresult Resolve(nsBlockFrame* aBlockFrame);
/**
* Reorder this line using Bidi engine.
* Update frame array, following the new visual sequence.
*
* @lina 05/02/2000
*/
void ReorderFrames(nsIFrame* aFirstFrameOnLine,
PRInt32 aNumFramesOnLine);
/**
* Format Unicode text, taking into account bidi capabilities
* of the platform. The formatting includes: reordering, Arabic shaping,
* symmetric and numeric swapping, removing control characters.
*
* @lina 06/18/2000
*/
nsresult FormatUnicodeText(nsPresContext* aPresContext,
PRUnichar* aText,
PRInt32& aTextLength,
nsCharType aCharType,
PRBool aIsOddLevel);
/**
* Reorder plain text using the Unicode Bidi algorithm and send it to
* a rendering context for rendering.
*
* @param[in] aText the string to be rendered (in logical order)
* @param aLength the number of characters in the string
* @param aBaseDirection the base direction of the string
* NSBIDI_LTR - left-to-right string
* NSBIDI_RTL - right-to-left string
* @param aPresContext the presentation context
* @param aRenderingContext the rendering context
* @param aX the x-coordinate to render the string
* @param aY the y-coordinate to render the string
* @param[in,out] aPosResolve array of logical positions to resolve into visual positions; can be nsnull if this functionality is not required
* @param aPosResolveCount number of items in the aPosResolve array
*/
nsresult RenderText(const PRUnichar* aText,
PRInt32 aLength,
nsBidiDirection aBaseDirection,
nsPresContext* aPresContext,
nsIRenderingContext& aRenderingContext,
nscoord aX,
nscoord aY,
nsBidiPositionResolve* aPosResolve = nsnull,
PRInt32 aPosResolveCount = 0)
{
return ProcessTextForRenderingContext(aText, aLength, aBaseDirection, aPresContext, aRenderingContext,
MODE_DRAW, aX, aY, aPosResolve, aPosResolveCount, nsnull);
}
nscoord MeasureTextWidth(const PRUnichar* aText,
PRInt32 aLength,
nsBidiDirection aBaseDirection,
nsPresContext* aPresContext,
nsIRenderingContext& aRenderingContext)
{
nscoord length;
nsresult rv = ProcessTextForRenderingContext(aText, aLength, aBaseDirection, aPresContext, aRenderingContext,
MODE_MEASURE, 0, 0, nsnull, 0, &length);
return NS_SUCCEEDED(rv) ? length : 0;
}
/**
* Check if a line is reordered, i.e., if the child frames are not
* all laid out left-to-right.
* @param aFirstFrameOnLine : first frame of the line to be tested
* @param aNumFramesOnLine : number of frames on this line
* @param[out] aLeftMost : leftmost frame on this line
* @param[out] aRightMost : rightmost frame on this line
*/
PRBool CheckLineOrder(nsIFrame* aFirstFrameOnLine,
PRInt32 aNumFramesOnLine,
nsIFrame** aLeftmost,
nsIFrame** aRightmost);
/**
* Get the frame to the right of the given frame, on the same line.
* @param aFrame : We're looking for the frame to the right of this frame.
* If null, return the leftmost frame on the line.
* @param aFirstFrameOnLine : first frame of the line to be tested
* @param aNumFramesOnLine : number of frames on this line
*/
nsIFrame* GetFrameToRightOf(const nsIFrame* aFrame,
nsIFrame* aFirstFrameOnLine,
PRInt32 aNumFramesOnLine);
/**
* Get the frame to the left of the given frame, on the same line.
* @param aFrame : We're looking for the frame to the left of this frame.
* If null, return the rightmost frame on the line.
* @param aFirstFrameOnLine : first frame of the line to be tested
* @param aNumFramesOnLine : number of frames on this line
*/
nsIFrame* GetFrameToLeftOf(const nsIFrame* aFrame,
nsIFrame* aFirstFrameOnLine,
PRInt32 aNumFramesOnLine);
/**
* Get the bidi embedding level of the given (inline) frame.
*/
static nsBidiLevel GetFrameEmbeddingLevel(nsIFrame* aFrame);
/**
* Get the bidi base level of the given (inline) frame.
*/
static nsBidiLevel GetFrameBaseLevel(nsIFrame* aFrame);
enum Mode { MODE_DRAW, MODE_MEASURE };
/**
* Reorder plain text using the Unicode Bidi algorithm and send it to
* a processor for rendering or measuring
*
* @param[in] aText the string to be processed (in logical order)
* @param aLength the number of characters in the string
* @param aBaseDirection the base direction of the string
* NSBIDI_LTR - left-to-right string
* NSBIDI_RTL - right-to-left string
* @param aPresContext the presentation context
* @param aprocessor the bidi processor
* @param aMode the operation to process
* MODE_DRAW - invokes DrawText on the processor for each substring
* MODE_MEASURE - does not invoke DrawText on the processor
* Note that the string is always measured, regardless of mode
* @param[in,out] aPosResolve array of logical positions to resolve into
* visual positions; can be nsnull if this functionality is not required
* @param aPosResolveCount number of items in the aPosResolve array
* @param[out] aWidth Pointer to where the width will be stored (may be null)
*/
nsresult ProcessText(const PRUnichar* aText,
PRInt32 aLength,
nsBidiDirection aBaseDirection,
nsPresContext* aPresContext,
BidiProcessor& aprocessor,
Mode aMode,
nsBidiPositionResolve* aPosResolve,
PRInt32 aPosResolveCount,
nscoord* aWidth);
/**
* Guess at how much memory is being used by this nsBidiPresUtils instance,
* including memory used by nsBidi.
*/
PRUint32 EstimateMemoryUsed();
private:
nsresult ProcessTextForRenderingContext(const PRUnichar* aText,
PRInt32 aLength,
nsBidiDirection aBaseDirection,
nsPresContext* aPresContext,
nsIRenderingContext& aRenderingContext,
Mode aMode,
nscoord aX, // DRAW only
nscoord aY, // DRAW only
nsBidiPositionResolve* aPosResolve, /* may be null */
PRInt32 aPosResolveCount,
nscoord* aWidth /* may be null */);
/**
* Create a string containing entire text content of this block.
*
* @lina 05/02/2000
*/
void CreateBlockBuffer();
/**
* Set up an array of the frames after splitting frames so that each frame has
* consistent directionality. At this point the frames are still in logical
* order
*/
void InitLogicalArray(nsIFrame* aCurrentFrame);
/**
* Initialize the logically-ordered array of frames
* using the top-level frames of a single line
*/
void InitLogicalArrayFromLine(nsIFrame* aFirstFrameOnLine,
PRInt32 aNumFramesOnLine);
/**
* Reorder the frame array from logical to visual order
*
* @param aReordered TRUE on return if the visual order is different from
* the logical order
* @param aHasRTLFrames TRUE on return if at least one of the frames is RTL
* (and therefore might have reordered descendents)
*/
nsresult Reorder(PRBool& aReordered, PRBool& aHasRTLFrames);
/*
* Position aFrame and it's descendants to their visual places. Also if aFrame
* is not leaf, resize it to embrace it's children.
*
* @param aFrame The frame which itself and its children are going
* to be repositioned
* @param aIsOddLevel TRUE means the embedding level of this frame is odd
* @param[in,out] aLeft IN value is the starting position of aFrame(without
* considering its left margin)
* OUT value will be the ending position of aFrame(after
* adding its right margin)
* @param aContinuationStates A map from nsIFrame* to nsFrameContinuationState
*/
void RepositionFrame(nsIFrame* aFrame,
PRBool aIsOddLevel,
nscoord& aLeft,
nsContinuationStates* aContinuationStates) const;
/*
* Initialize the continuation state(nsFrameContinuationState) to
* (nsnull, 0) for aFrame and its descendants.
*
* @param aFrame The frame which itself and its descendants will
* be initialized
* @param aContinuationStates A map from nsIFrame* to nsFrameContinuationState
*/
void InitContinuationStates(nsIFrame* aFrame,
nsContinuationStates* aContinuationStates) const;
/*
* Determine if aFrame is leftmost or rightmost, and set aIsLeftMost and
* aIsRightMost values. Also set continuation states of aContinuationStates.
*
* A frame is leftmost if it's the first appearance of its continuation chain
* on the line and the chain is on its first line if it's LTR or the chain is
* on its last line if it's RTL.
* A frame is rightmost if it's the last appearance of its continuation chain
* on the line and the chain is on its first line if it's RTL or the chain is
* on its last line if it's LTR.
*
* @param aContinuationStates A map from nsIFrame* to nsFrameContinuationState
* @param[out] aIsLeftMost TRUE means aFrame is leftmost frame or continuation
* @param[out] aIsRightMost TRUE means aFrame is rightmost frame or continuation
*/
void IsLeftOrRightMost(nsIFrame* aFrame,
nsContinuationStates* aContinuationStates,
PRBool& aIsLeftMost /* out */,
PRBool& aIsRightMost /* out */) const;
/**
* Adjust frame positions following their visual order
*
* @param aFirstChild the first kid
*
* @lina 04/11/2000
*/
void RepositionInlineFrames(nsIFrame* aFirstChild) const;
/**
* Helper method for Resolve()
* Truncate a text frame to the end of a single-directional run and possibly
* create a continuation frame for the remainder of its content.
*
* @param aFrame the original frame
* @param aNewFrame [OUT] the new frame that was created
* @param aFrameIndex [IN/OUT] index of aFrame in mLogicalFrames
* @param aStart [IN] the start of the content mapped by aFrame (and
* any fluid continuations)
* @param aEnd [IN] the offset of the end of the single-directional
* text run.
* @see Resolve()
* @see RemoveBidiContinuation()
*/
inline
void EnsureBidiContinuation(nsIFrame* aFrame,
nsIFrame** aNewFrame,
PRInt32& aFrameIndex,
PRInt32 aStart,
PRInt32 aEnd);
/**
* Helper method for Resolve()
* Convert one or more bidi continuation frames created in a previous reflow by
* EnsureBidiContinuation() into fluid continuations.
* @param aFrame the frame whose continuations are to be removed
* @param aFirstIndex index of aFrame in mLogicalFrames
* @param aLastIndex index of the last frame to be removed
* @param aOffset [OUT] count of directional frames removed. Since
* directional frames have control characters
* corresponding to them in mBuffer, the pointers to
* mBuffer in Resolve() will need to be updated after
* deleting the frames.
*
* @see Resolve()
* @see EnsureBidiContinuation()
*/
void RemoveBidiContinuation(nsIFrame* aFrame,
PRInt32 aFirstIndex,
PRInt32 aLastIndex,
PRInt32& aOffset) const;
void CalculateCharType(PRInt32& aOffset,
PRInt32 aCharTypeLimit,
PRInt32& aRunLimit,
PRInt32& aRunLength,
PRInt32& aRunCount,
PRUint8& aCharType,
PRUint8& aPrevCharType) const;
void StripBidiControlCharacters(PRUnichar* aText,
PRInt32& aTextLength) const;
nsAutoString mBuffer;
nsTArray<nsIFrame*> mLogicalFrames;
nsTArray<nsIFrame*> mVisualFrames;
nsDataHashtable<nsISupportsHashKey, PRInt32> mContentToFrameIndex;
PRInt32 mArraySize;
PRInt32* mIndexMap;
PRUint8* mLevels;
nsresult mSuccess;
nsBidi* mBidiEngine;
};
#endif /* nsBidiPresUtils_h___ */
#endif // IBMBIDI
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