mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-05 08:35:26 +00:00
533 lines
23 KiB
C++
533 lines
23 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/. */
|
|
|
|
#ifndef nsBidiPresUtils_h___
|
|
#define nsBidiPresUtils_h___
|
|
|
|
#include "nsBidi.h"
|
|
#include "nsBidiUtils.h"
|
|
#include "nsHashKeys.h"
|
|
#include "nsCoord.h"
|
|
|
|
#ifdef DrawText
|
|
#undef DrawText
|
|
#endif
|
|
|
|
struct BidiParagraphData;
|
|
struct BidiLineData;
|
|
class nsFontMetrics;
|
|
class nsIFrame;
|
|
class nsBlockFrame;
|
|
class nsPresContext;
|
|
class nsRenderingContext;
|
|
class nsBlockInFlowLineIterator;
|
|
class nsStyleContext;
|
|
template<class T> class nsTHashtable;
|
|
namespace mozilla { class WritingMode; }
|
|
|
|
/**
|
|
* 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
|
|
{
|
|
explicit nsFrameContinuationState(const void *aFrame) : nsVoidPtrHashKey(aFrame) {}
|
|
|
|
/**
|
|
* The first visual frame in the continuation chain containing this frame, or
|
|
* nullptr 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.
|
|
*/
|
|
uint32_t 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.
|
|
*/
|
|
bool 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.
|
|
*/
|
|
bool 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.
|
|
int32_t logicalIndex;
|
|
// [out] Visual index within string.
|
|
// If the logical position was not found, set to kNotFound.
|
|
int32_t 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.
|
|
int32_t visualLeftTwips;
|
|
// [out] Visual width of the character, in twips.
|
|
// If the logical position was not found, set to kNotFound.
|
|
int32_t visualWidth;
|
|
};
|
|
|
|
class nsBidiPresUtils {
|
|
public:
|
|
nsBidiPresUtils();
|
|
~nsBidiPresUtils();
|
|
|
|
/**
|
|
* 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 char16_t* aText,
|
|
int32_t 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
|
|
*/
|
|
static nsresult Resolve(nsBlockFrame* aBlockFrame);
|
|
static nsresult ResolveParagraph(nsBlockFrame* aBlockFrame,
|
|
BidiParagraphData* aBpd);
|
|
static void ResolveParagraphWithinBlock(nsBlockFrame* aBlockFrame,
|
|
BidiParagraphData* aBpd);
|
|
|
|
/**
|
|
* Reorder this line using Bidi engine.
|
|
* Update frame array, following the new visual sequence.
|
|
*
|
|
* @lina 05/02/2000
|
|
*/
|
|
static void ReorderFrames(nsIFrame* aFirstFrameOnLine,
|
|
int32_t aNumFramesOnLine,
|
|
mozilla::WritingMode aLineWM,
|
|
nscoord aLineWidth,
|
|
nscoord aStart);
|
|
|
|
/**
|
|
* 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
|
|
*/
|
|
static nsresult FormatUnicodeText(nsPresContext* aPresContext,
|
|
char16_t* aText,
|
|
int32_t& aTextLength,
|
|
nsCharType aCharType,
|
|
bool 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 aBaseLevel the base embedding level of the string
|
|
* odd values are right-to-left; even values are left-to-right, plus special
|
|
* constants as follows (defined in nsBidi.h)
|
|
* NSBIDI_LTR - left-to-right string
|
|
* NSBIDI_RTL - right-to-left string
|
|
* NSBIDI_DEFAULT_LTR - auto direction determined by first strong character,
|
|
* default is left-to-right
|
|
* NSBIDI_DEFAULT_RTL - auto direction determined by first strong character,
|
|
* default is right-to-left
|
|
*
|
|
* @param aPresContext the presentation context
|
|
* @param aRenderingContext the rendering context to render to
|
|
* @param aTextRunConstructionContext the rendering context to be used to construct the textrun (affects font hinting)
|
|
* @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 nullptr if this functionality is not required
|
|
* @param aPosResolveCount number of items in the aPosResolve array
|
|
*/
|
|
static nsresult RenderText(const char16_t* aText,
|
|
int32_t aLength,
|
|
nsBidiLevel aBaseLevel,
|
|
nsPresContext* aPresContext,
|
|
nsRenderingContext& aRenderingContext,
|
|
nsRenderingContext& aTextRunConstructionContext,
|
|
nsFontMetrics& aFontMetrics,
|
|
nscoord aX,
|
|
nscoord aY,
|
|
nsBidiPositionResolve* aPosResolve = nullptr,
|
|
int32_t aPosResolveCount = 0)
|
|
{
|
|
return ProcessTextForRenderingContext(aText, aLength, aBaseLevel, aPresContext, aRenderingContext,
|
|
aTextRunConstructionContext,
|
|
aFontMetrics,
|
|
MODE_DRAW, aX, aY, aPosResolve, aPosResolveCount, nullptr);
|
|
}
|
|
|
|
static nscoord MeasureTextWidth(const char16_t* aText,
|
|
int32_t aLength,
|
|
nsBidiLevel aBaseLevel,
|
|
nsPresContext* aPresContext,
|
|
nsRenderingContext& aRenderingContext,
|
|
nsFontMetrics& aFontMetrics)
|
|
{
|
|
nscoord length;
|
|
nsresult rv = ProcessTextForRenderingContext(aText, aLength, aBaseLevel, aPresContext,
|
|
aRenderingContext, aRenderingContext,
|
|
aFontMetrics,
|
|
MODE_MEASURE, 0, 0, nullptr, 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
|
|
*/
|
|
static bool CheckLineOrder(nsIFrame* aFirstFrameOnLine,
|
|
int32_t 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
|
|
*/
|
|
static nsIFrame* GetFrameToRightOf(const nsIFrame* aFrame,
|
|
nsIFrame* aFirstFrameOnLine,
|
|
int32_t 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
|
|
*/
|
|
static nsIFrame* GetFrameToLeftOf(const nsIFrame* aFrame,
|
|
nsIFrame* aFirstFrameOnLine,
|
|
int32_t aNumFramesOnLine);
|
|
|
|
static nsIFrame* GetFirstLeaf(nsIFrame* aFrame);
|
|
|
|
/**
|
|
* Get the bidi embedding level of the given (inline) frame.
|
|
*/
|
|
static nsBidiLevel GetFrameEmbeddingLevel(nsIFrame* aFrame);
|
|
|
|
/**
|
|
* Get the paragraph depth of the given (inline) frame.
|
|
*/
|
|
static uint8_t GetParagraphDepth(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 aBaseLevel the base embedding level of the string
|
|
* odd values are right-to-left; even values are left-to-right, plus special
|
|
* constants as follows (defined in nsBidi.h)
|
|
* NSBIDI_LTR - left-to-right string
|
|
* NSBIDI_RTL - right-to-left string
|
|
* NSBIDI_DEFAULT_LTR - auto direction determined by first strong character,
|
|
* default is left-to-right
|
|
* NSBIDI_DEFAULT_RTL - auto direction determined by first strong character,
|
|
* default is right-to-left
|
|
*
|
|
* @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 nullptr 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)
|
|
*/
|
|
static nsresult ProcessText(const char16_t* aText,
|
|
int32_t aLength,
|
|
nsBidiLevel aBaseLevel,
|
|
nsPresContext* aPresContext,
|
|
BidiProcessor& aprocessor,
|
|
Mode aMode,
|
|
nsBidiPositionResolve* aPosResolve,
|
|
int32_t aPosResolveCount,
|
|
nscoord* aWidth,
|
|
nsBidi* aBidiEngine);
|
|
|
|
/**
|
|
* Make a copy of a string, converting from logical to visual order
|
|
*
|
|
* @param aSource the source string
|
|
* @param aDest the destination string
|
|
* @param aBaseDirection the base direction of the string
|
|
* (NSBIDI_LTR or NSBIDI_RTL to force the base direction;
|
|
* NSBIDI_DEFAULT_LTR or NSBIDI_DEFAULT_RTL to let the bidi engine
|
|
* determine the direction from rules P2 and P3 of the bidi algorithm.
|
|
* @see nsBidi::GetPara
|
|
* @param aOverride if TRUE, the text has a bidi override, according to
|
|
* the direction in aDir
|
|
*/
|
|
static void CopyLogicalToVisual(const nsAString& aSource,
|
|
nsAString& aDest,
|
|
nsBidiLevel aBaseDirection,
|
|
bool aOverride);
|
|
|
|
/**
|
|
* Use style attributes to determine the base paragraph level to pass to the
|
|
* bidi algorithm.
|
|
*
|
|
* If |unicode-bidi| is set to "[-moz-]plaintext", returns NSBIDI_DEFAULT_LTR,
|
|
* in other words the direction is determined from the first strong character
|
|
* in the text according to rules P2 and P3 of the bidi algorithm, or LTR if
|
|
* there is no strong character.
|
|
*
|
|
* Otherwise returns NSBIDI_LTR or NSBIDI_RTL depending on the value of
|
|
* |direction|
|
|
*/
|
|
static nsBidiLevel BidiLevelFromStyle(nsStyleContext* aStyleContext);
|
|
|
|
private:
|
|
static nsresult
|
|
ProcessTextForRenderingContext(const char16_t* aText,
|
|
int32_t aLength,
|
|
nsBidiLevel aBaseLevel,
|
|
nsPresContext* aPresContext,
|
|
nsRenderingContext& aRenderingContext,
|
|
nsRenderingContext& aTextRunConstructionContext,
|
|
nsFontMetrics& aFontMetrics,
|
|
Mode aMode,
|
|
nscoord aX, // DRAW only
|
|
nscoord aY, // DRAW only
|
|
nsBidiPositionResolve* aPosResolve, /* may be null */
|
|
int32_t aPosResolveCount,
|
|
nscoord* aWidth /* may be null */);
|
|
|
|
/**
|
|
* Traverse the child frames of the block element and:
|
|
* Set up an array of the frames in logical order
|
|
* Create a string containing the text content of all the frames
|
|
* If we encounter content that requires us to split the element into more
|
|
* than one paragraph for bidi resolution, resolve the paragraph up to that
|
|
* point.
|
|
*/
|
|
static void TraverseFrames(nsBlockFrame* aBlockFrame,
|
|
nsBlockInFlowLineIterator* aLineIter,
|
|
nsIFrame* aCurrentFrame,
|
|
BidiParagraphData* aBpd);
|
|
|
|
/*
|
|
* Position aFrame and its descendants to their visual places. Also if aFrame
|
|
* is not leaf, resize it to embrace its children.
|
|
*
|
|
* @param aFrame The frame which itself and its children are
|
|
* going to be repositioned
|
|
* @param aIsEvenLevel TRUE means the embedding level of this frame
|
|
* is even (LTR)
|
|
* @param[in,out] aStart IN value is the starting position of aFrame
|
|
* (without considering its inline-start margin)
|
|
* OUT value will be the ending position of aFrame
|
|
* (after adding its inline-end margin)
|
|
* @param aContinuationStates A map from nsIFrame* to nsFrameContinuationState
|
|
*/
|
|
static void RepositionFrame(nsIFrame* aFrame,
|
|
bool aIsEvenLevel,
|
|
nscoord& aStart,
|
|
nsContinuationStates* aContinuationStates,
|
|
mozilla::WritingMode aContainerWM,
|
|
nscoord aContainerWidth);
|
|
|
|
/*
|
|
* Initialize the continuation state(nsFrameContinuationState) to
|
|
* (nullptr, 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
|
|
*/
|
|
static void InitContinuationStates(nsIFrame* aFrame,
|
|
nsContinuationStates* aContinuationStates);
|
|
|
|
/*
|
|
* Determine if aFrame is first or last, and set aIsFirst and
|
|
* aIsLast values. Also set continuation states of
|
|
* aContinuationStates.
|
|
*
|
|
* A frame is first if it's the first appearance of its continuation
|
|
* chain on the line and the chain is on its first line.
|
|
* A frame is last if it's the last appearance of its continuation
|
|
* chain on the line and the chain is on its last line.
|
|
*
|
|
* N.B: "First appearance" and "Last appearance" in the previous
|
|
* paragraph refer to the frame's inline direction, not necessarily
|
|
* the line's.
|
|
*
|
|
* @param aContinuationStates A map from nsIFrame* to
|
|
* nsFrameContinuationState
|
|
* @param[in] aSpanDirMatchesLineDir TRUE means that the inline
|
|
* direction of aFrame is the same
|
|
* as its container
|
|
* @param[out] aIsFirst TRUE means aFrame is first frame
|
|
* or continuation
|
|
* @param[out] aIsLast TRUE means aFrame is last frame
|
|
* or continuation
|
|
*/
|
|
static void IsFirstOrLast(nsIFrame* aFrame,
|
|
nsContinuationStates* aContinuationStates,
|
|
bool aSpanInLineOrder /* in */,
|
|
bool& aIsFirst /* out */,
|
|
bool& aIsLast /* out */);
|
|
|
|
/**
|
|
* Adjust frame positions following their visual order
|
|
*
|
|
* @param aFirstChild the first kid
|
|
*
|
|
* @lina 04/11/2000
|
|
*/
|
|
static void RepositionInlineFrames(BidiLineData* aBld,
|
|
nsIFrame* aFirstChild,
|
|
mozilla::WritingMode aLineWM,
|
|
nscoord aLineWidth,
|
|
nscoord aStart);
|
|
|
|
/**
|
|
* 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()
|
|
*/
|
|
static inline
|
|
nsresult EnsureBidiContinuation(nsIFrame* aFrame,
|
|
nsIFrame** aNewFrame,
|
|
int32_t& aFrameIndex,
|
|
int32_t aStart,
|
|
int32_t 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()
|
|
*/
|
|
static void RemoveBidiContinuation(BidiParagraphData* aBpd,
|
|
nsIFrame* aFrame,
|
|
int32_t aFirstIndex,
|
|
int32_t aLastIndex,
|
|
int32_t& aOffset);
|
|
static void CalculateCharType(nsBidi* aBidiEngine,
|
|
const char16_t* aText,
|
|
int32_t& aOffset,
|
|
int32_t aCharTypeLimit,
|
|
int32_t& aRunLimit,
|
|
int32_t& aRunLength,
|
|
int32_t& aRunCount,
|
|
uint8_t& aCharType,
|
|
uint8_t& aPrevCharType);
|
|
|
|
static void StripBidiControlCharacters(char16_t* aText,
|
|
int32_t& aTextLength);
|
|
|
|
static bool WriteLogicalToVisual(const char16_t* aSrc,
|
|
uint32_t aSrcLength,
|
|
char16_t* aDest,
|
|
nsBidiLevel aBaseDirection,
|
|
nsBidi* aBidiEngine);
|
|
|
|
static void WriteReverse(const char16_t* aSrc,
|
|
uint32_t aSrcLength,
|
|
char16_t* aDest);
|
|
};
|
|
|
|
#endif /* nsBidiPresUtils_h___ */
|