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gecko-dev/gfx/thebes/gfxTextRun.h

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=4 et sw=4 tw=80:
* 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 GFX_TEXTRUN_H
#define GFX_TEXTRUN_H
#include "gfxTypes.h"
#include "nsString.h"
#include "gfxPoint.h"
#include "gfxFont.h"
#include "gfxFontConstants.h"
#include "nsTArray.h"
#include "gfxSkipChars.h"
#include "gfxPlatform.h"
#include "mozilla/MemoryReporting.h"
#include "DrawMode.h"
#include "harfbuzz/hb.h"
#include "nsUnicodeScriptCodes.h"
#ifdef DEBUG
#include <stdio.h>
#endif
class gfxContext;
class gfxFontGroup;
class gfxUserFontEntry;
class gfxUserFontSet;
class gfxTextContextPaint;
class nsIAtom;
class nsILanguageAtomService;
class gfxMissingFontRecorder;
/**
* Callback for Draw() to use when drawing text with mode
* DrawMode::GLYPH_PATH.
*/
struct gfxTextRunDrawCallbacks {
/**
* Constructs a new DrawCallbacks object.
*
* @param aShouldPaintSVGGlyphs If true, SVG glyphs will be painted. If
* false, SVG glyphs will not be painted; fallback plain glyphs are not
* emitted either.
*/
explicit gfxTextRunDrawCallbacks(bool aShouldPaintSVGGlyphs = false)
: mShouldPaintSVGGlyphs(aShouldPaintSVGGlyphs)
{
}
/**
* Called when a path has been emitted to the gfxContext when
* painting a text run. This can be called any number of times,
* due to partial ligatures and intervening SVG glyphs.
*/
virtual void NotifyGlyphPathEmitted() = 0;
bool mShouldPaintSVGGlyphs;
};
/**
* gfxTextRun is an abstraction for drawing and measuring substrings of a run
* of text. It stores runs of positioned glyph data, each run having a single
* gfxFont. The glyphs are associated with a string of source text, and the
* gfxTextRun APIs take parameters that are offsets into that source text.
*
* gfxTextRuns are not refcounted. They should be deleted when no longer required.
*
* gfxTextRuns are mostly immutable. The only things that can change are
* inter-cluster spacing and line break placement. Spacing is always obtained
* lazily by methods that need it, it is not cached. Line breaks are stored
* persistently (insofar as they affect the shaping of glyphs; gfxTextRun does
* not actually do anything to explicitly account for line breaks). Initially
* there are no line breaks. The textrun can record line breaks before or after
* any given cluster. (Line breaks specified inside clusters are ignored.)
*
* It is important that zero-length substrings are handled correctly. This will
* be on the test!
*/
class gfxTextRun : public gfxShapedText {
public:
// Override operator delete to properly free the object that was
// allocated via malloc.
void operator delete(void* p) {
free(p);
}
virtual ~gfxTextRun();
typedef gfxFont::RunMetrics Metrics;
// Public textrun API for general use
bool IsClusterStart(uint32_t aPos) const {
NS_ASSERTION(aPos < GetLength(), "aPos out of range");
return mCharacterGlyphs[aPos].IsClusterStart();
}
bool IsLigatureGroupStart(uint32_t aPos) const {
NS_ASSERTION(aPos < GetLength(), "aPos out of range");
return mCharacterGlyphs[aPos].IsLigatureGroupStart();
}
bool CanBreakLineBefore(uint32_t aPos) const {
return CanBreakBefore(aPos) == CompressedGlyph::FLAG_BREAK_TYPE_NORMAL;
}
bool CanHyphenateBefore(uint32_t aPos) const {
return CanBreakBefore(aPos) == CompressedGlyph::FLAG_BREAK_TYPE_HYPHEN;
}
// Returns a gfxShapedText::CompressedGlyph::FLAG_BREAK_TYPE_* value
// as defined in gfxFont.h (may be NONE, NORMAL or HYPHEN).
uint8_t CanBreakBefore(uint32_t aPos) const {
NS_ASSERTION(aPos < GetLength(), "aPos out of range");
return mCharacterGlyphs[aPos].CanBreakBefore();
}
bool CharIsSpace(uint32_t aPos) const {
NS_ASSERTION(aPos < GetLength(), "aPos out of range");
return mCharacterGlyphs[aPos].CharIsSpace();
}
bool CharIsTab(uint32_t aPos) const {
NS_ASSERTION(aPos < GetLength(), "aPos out of range");
return mCharacterGlyphs[aPos].CharIsTab();
}
bool CharIsNewline(uint32_t aPos) const {
NS_ASSERTION(aPos < GetLength(), "aPos out of range");
return mCharacterGlyphs[aPos].CharIsNewline();
}
// All uint32_t aStart, uint32_t aLength ranges below are restricted to
// grapheme cluster boundaries! All offsets are in terms of the string
// passed into MakeTextRun.
// All coordinates are in layout/app units
/**
* Set the potential linebreaks for a substring of the textrun. These are
* the "allow break before" points. Initially, there are no potential
* linebreaks.
*
* This can change glyphs and/or geometry! Some textruns' shapes
* depend on potential line breaks (e.g., title-case-converting textruns).
* This function is virtual so that those textruns can reshape themselves.
*
* @return true if this changed the linebreaks, false if the new line
* breaks are the same as the old
*/
virtual bool SetPotentialLineBreaks(uint32_t aStart, uint32_t aLength,
uint8_t *aBreakBefore,
gfxContext *aRefContext);
/**
* Layout provides PropertyProvider objects. These allow detection of
* potential line break points and computation of spacing. We pass the data
* this way to allow lazy data acquisition; for example BreakAndMeasureText
* will want to only ask for properties of text it's actually looking at.
*
* NOTE that requested spacing may not actually be applied, if the textrun
* is unable to apply it in some context. Exception: spacing around a
* whitespace character MUST always be applied.
*/
class PropertyProvider {
public:
// Detect hyphenation break opportunities in the given range; breaks
// not at cluster boundaries will be ignored.
virtual void GetHyphenationBreaks(uint32_t aStart, uint32_t aLength,
bool *aBreakBefore) = 0;
// Returns the provider's hyphenation setting, so callers can decide
// whether it is necessary to call GetHyphenationBreaks.
// Result is an NS_STYLE_HYPHENS_* value.
virtual int8_t GetHyphensOption() = 0;
// Returns the extra width that will be consumed by a hyphen. This should
// be constant for a given textrun.
virtual gfxFloat GetHyphenWidth() = 0;
typedef gfxFont::Spacing Spacing;
/**
* Get the spacing around the indicated characters. Spacing must be zero
* inside clusters. In other words, if character i is not
* CLUSTER_START, then character i-1 must have zero after-spacing and
* character i must have zero before-spacing.
*/
virtual void GetSpacing(uint32_t aStart, uint32_t aLength,
Spacing *aSpacing) = 0;
// Returns a gfxContext that can be used to measure the hyphen glyph.
// Only called if the hyphen width is requested.
virtual already_AddRefed<gfxContext> GetContext() = 0;
// Return the appUnitsPerDevUnit value to be used when measuring.
// Only called if the hyphen width is requested.
virtual uint32_t GetAppUnitsPerDevUnit() = 0;
};
class ClusterIterator {
public:
explicit ClusterIterator(gfxTextRun *aTextRun);
void Reset();
bool NextCluster();
uint32_t Position() const {
return mCurrentChar;
}
uint32_t ClusterLength() const;
gfxFloat ClusterAdvance(PropertyProvider *aProvider) const;
private:
gfxTextRun *mTextRun;
uint32_t mCurrentChar;
};
/**
* Draws a substring. Uses only GetSpacing from aBreakProvider.
* The provided point is the baseline origin on the left of the string
* for LTR, on the right of the string for RTL.
* @param aAdvanceWidth if non-null, the advance width of the substring
* is returned here.
*
* Drawing should respect advance widths in the sense that for LTR runs,
* Draw(ctx, pt, offset1, length1, dirty, &provider, &advance) followed by
* Draw(ctx, gfxPoint(pt.x + advance, pt.y), offset1 + length1, length2,
* dirty, &provider, nullptr) should have the same effect as
* Draw(ctx, pt, offset1, length1+length2, dirty, &provider, nullptr).
* For RTL runs the rule is:
* Draw(ctx, pt, offset1 + length1, length2, dirty, &provider, &advance) followed by
* Draw(ctx, gfxPoint(pt.x + advance, pt.y), offset1, length1,
* dirty, &provider, nullptr) should have the same effect as
* Draw(ctx, pt, offset1, length1+length2, dirty, &provider, nullptr).
*
* Glyphs should be drawn in logical content order, which can be significant
* if they overlap (perhaps due to negative spacing).
*/
void Draw(gfxContext *aContext, gfxPoint aPt,
DrawMode aDrawMode,
uint32_t aStart, uint32_t aLength,
PropertyProvider *aProvider,
gfxFloat *aAdvanceWidth, gfxTextContextPaint *aContextPaint,
gfxTextRunDrawCallbacks *aCallbacks = nullptr);
/**
* Computes the ReflowMetrics for a substring.
* Uses GetSpacing from aBreakProvider.
* @param aBoundingBoxType which kind of bounding box (loose/tight)
*/
Metrics MeasureText(uint32_t aStart, uint32_t aLength,
gfxFont::BoundingBoxType aBoundingBoxType,
gfxContext *aRefContextForTightBoundingBox,
PropertyProvider *aProvider);
/**
* Computes just the advance width for a substring.
* Uses GetSpacing from aBreakProvider.
* If aSpacing is not null, the spacing attached before and after
* the substring would be returned in it. NOTE: the spacing is
* included in the advance width.
*/
gfxFloat GetAdvanceWidth(uint32_t aStart, uint32_t aLength,
PropertyProvider *aProvider,
PropertyProvider::Spacing* aSpacing = nullptr);
/**
* Clear all stored line breaks for the given range (both before and after),
* and then set the line-break state before aStart to aBreakBefore and
* after the last cluster to aBreakAfter.
*
* We require that before and after line breaks be consistent. For clusters
* i and i+1, we require that if there is a break after cluster i, a break
* will be specified before cluster i+1. This may be temporarily violated
* (e.g. after reflowing line L and before reflowing line L+1); to handle
* these temporary violations, we say that there is a break betwen i and i+1
* if a break is specified after i OR a break is specified before i+1.
*
* This can change textrun geometry! The existence of a linebreak can affect
* the advance width of the cluster before the break (when kerning) or the
* geometry of one cluster before the break or any number of clusters
* after the break. (The one-cluster-before-the-break limit is somewhat
* arbitrary; if some scripts require breaking it, then we need to
* alter nsTextFrame::TrimTrailingWhitespace, perhaps drastically becase
* it could affect the layout of frames before it...)
*
* We return true if glyphs or geometry changed, false otherwise. This
* function is virtual so that gfxTextRun subclasses can reshape
* properly.
*
* @param aAdvanceWidthDelta if non-null, returns the change in advance
* width of the given range.
*/
virtual bool SetLineBreaks(uint32_t aStart, uint32_t aLength,
bool aLineBreakBefore, bool aLineBreakAfter,
gfxFloat *aAdvanceWidthDelta,
gfxContext *aRefContext);
enum SuppressBreak {
eNoSuppressBreak,
// Measure the range of text as if there is no break before it.
eSuppressInitialBreak,
// Measure the range of text as if it contains no break
eSuppressAllBreaks
};
/**
* Finds the longest substring that will fit into the given width.
* Uses GetHyphenationBreaks and GetSpacing from aBreakProvider.
* Guarantees the following:
* -- 0 <= result <= aMaxLength
* -- result is the maximal value of N such that either
* N < aMaxLength && line break at N && GetAdvanceWidth(aStart, N) <= aWidth
* OR N < aMaxLength && hyphen break at N && GetAdvanceWidth(aStart, N) + GetHyphenWidth() <= aWidth
* OR N == aMaxLength && GetAdvanceWidth(aStart, N) <= aWidth
* where GetAdvanceWidth assumes the effect of
* SetLineBreaks(aStart, N, aLineBreakBefore, N < aMaxLength, aProvider)
* -- if no such N exists, then result is the smallest N such that
* N < aMaxLength && line break at N
* OR N < aMaxLength && hyphen break at N
* OR N == aMaxLength
*
* The call has the effect of
* SetLineBreaks(aStart, result, aLineBreakBefore, result < aMaxLength, aProvider)
* and the returned metrics and the invariants above reflect this.
*
* @param aMaxLength this can be UINT32_MAX, in which case the length used
* is up to the end of the string
* @param aLineBreakBefore set to true if and only if there is an actual
* line break at the start of this string.
* @param aSuppressBreak what break should be suppressed.
* @param aTrimWhitespace if non-null, then we allow a trailing run of
* spaces to be trimmed; the width of the space(s) will not be included in
* the measured string width for comparison with the limit aWidth, and
* trimmed spaces will not be included in returned metrics. The width
* of the trimmed spaces will be returned in aTrimWhitespace.
* Trimmed spaces are still counted in the "characters fit" result.
* @param aMetrics if non-null, we fill this in for the returned substring.
* If a hyphenation break was used, the hyphen is NOT included in the returned metrics.
* @param aBoundingBoxType whether to make the bounding box in aMetrics tight
* @param aRefContextForTightBoundingBox a reference context to get the
* tight bounding box, if requested
* @param aUsedHyphenation if non-null, records if we selected a hyphenation break
* @param aLastBreak if non-null and result is aMaxLength, we set this to
* the maximal N such that
* N < aMaxLength && line break at N && GetAdvanceWidth(aStart, N) <= aWidth
* OR N < aMaxLength && hyphen break at N && GetAdvanceWidth(aStart, N) + GetHyphenWidth() <= aWidth
* or UINT32_MAX if no such N exists, where GetAdvanceWidth assumes
* the effect of
* SetLineBreaks(aStart, N, aLineBreakBefore, N < aMaxLength, aProvider)
*
* @param aCanWordWrap true if we can break between any two grapheme
* clusters. This is set by word-wrap: break-word
*
* @param aBreakPriority in/out the priority of the break opportunity
* saved in the line. If we are prioritizing break opportunities, we will
* not set a break with a lower priority. @see gfxBreakPriority.
*
* Note that negative advance widths are possible especially if negative
* spacing is provided.
*/
uint32_t BreakAndMeasureText(uint32_t aStart, uint32_t aMaxLength,
bool aLineBreakBefore, gfxFloat aWidth,
PropertyProvider *aProvider,
SuppressBreak aSuppressBreak,
gfxFloat *aTrimWhitespace,
Metrics *aMetrics,
gfxFont::BoundingBoxType aBoundingBoxType,
gfxContext *aRefContextForTightBoundingBox,
bool *aUsedHyphenation,
uint32_t *aLastBreak,
bool aCanWordWrap,
gfxBreakPriority *aBreakPriority);
/**
* Update the reference context.
* XXX this is a hack. New text frame does not call this. Use only
* temporarily for old text frame.
*/
void SetContext(gfxContext *aContext) {}
// Utility getters
void *GetUserData() const { return mUserData; }
void SetUserData(void *aUserData) { mUserData = aUserData; }
void SetFlagBits(uint32_t aFlags) {
NS_ASSERTION(!(aFlags & ~gfxTextRunFactory::SETTABLE_FLAGS),
"Only user flags should be mutable");
mFlags |= aFlags;
}
void ClearFlagBits(uint32_t aFlags) {
NS_ASSERTION(!(aFlags & ~gfxTextRunFactory::SETTABLE_FLAGS),
"Only user flags should be mutable");
mFlags &= ~aFlags;
}
const gfxSkipChars& GetSkipChars() const { return mSkipChars; }
gfxFontGroup *GetFontGroup() const { return mFontGroup; }
// Call this, don't call "new gfxTextRun" directly. This does custom
// allocation and initialization
static gfxTextRun *Create(const gfxTextRunFactory::Parameters *aParams,
uint32_t aLength, gfxFontGroup *aFontGroup,
uint32_t aFlags);
// The text is divided into GlyphRuns as necessary
struct GlyphRun {
RefPtr<gfxFont> mFont; // never null
uint32_t mCharacterOffset; // into original UTF16 string
uint8_t mMatchType;
uint16_t mOrientation; // gfxTextRunFactory::TEXT_ORIENT_* value
};
class GlyphRunIterator {
public:
GlyphRunIterator(gfxTextRun *aTextRun, uint32_t aStart, uint32_t aLength)
: mTextRun(aTextRun), mStartOffset(aStart), mEndOffset(aStart + aLength) {
mNextIndex = mTextRun->FindFirstGlyphRunContaining(aStart);
}
bool NextRun();
GlyphRun *GetGlyphRun() { return mGlyphRun; }
uint32_t GetStringStart() { return mStringStart; }
uint32_t GetStringEnd() { return mStringEnd; }
private:
gfxTextRun *mTextRun;
GlyphRun *mGlyphRun;
uint32_t mStringStart;
uint32_t mStringEnd;
uint32_t mNextIndex;
uint32_t mStartOffset;
uint32_t mEndOffset;
};
class GlyphRunOffsetComparator {
public:
bool Equals(const GlyphRun& a,
const GlyphRun& b) const
{
return a.mCharacterOffset == b.mCharacterOffset;
}
bool LessThan(const GlyphRun& a,
const GlyphRun& b) const
{
return a.mCharacterOffset < b.mCharacterOffset;
}
};
friend class GlyphRunIterator;
friend class FontSelector;
// API for setting up the textrun glyphs. Should only be called by
// things that construct textruns.
/**
* We've found a run of text that should use a particular font. Call this
* only during initialization when font substitution has been computed.
* Call it before setting up the glyphs for the characters in this run;
* SetMissingGlyph requires that the correct glyphrun be installed.
*
* If aForceNewRun, a new glyph run will be added, even if the
* previously added run uses the same font. If glyph runs are
* added out of strictly increasing aStartCharIndex order (via
* force), then SortGlyphRuns must be called after all glyph runs
* are added before any further operations are performed with this
* TextRun.
*/
nsresult AddGlyphRun(gfxFont *aFont, uint8_t aMatchType,
uint32_t aStartCharIndex, bool aForceNewRun,
uint16_t aOrientation);
void ResetGlyphRuns() { mGlyphRuns.Clear(); }
void SortGlyphRuns();
void SanitizeGlyphRuns();
CompressedGlyph* GetCharacterGlyphs() {
NS_ASSERTION(mCharacterGlyphs, "failed to initialize mCharacterGlyphs");
return mCharacterGlyphs;
}
// clean out results from shaping in progress, used for fallback scenarios
void ClearGlyphsAndCharacters();
void SetSpaceGlyph(gfxFont *aFont, gfxContext *aContext, uint32_t aCharIndex,
uint16_t aOrientation);
// Set the glyph data for the given character index to the font's
// space glyph, IF this can be done as a "simple" glyph record
// (not requiring a DetailedGlyph entry). This avoids the need to call
// the font shaper and go through the shaped-word cache for most spaces.
//
// The parameter aSpaceChar is the original character code for which
// this space glyph is being used; if this is U+0020, we need to record
// that it could be trimmed at a run edge, whereas other kinds of space
// (currently just U+00A0) would not be trimmable/breakable.
//
// Returns true if it was able to set simple glyph data for the space;
// if it returns false, the caller needs to fall back to some other
// means to create the necessary (detailed) glyph data.
bool SetSpaceGlyphIfSimple(gfxFont *aFont, gfxContext *aContext,
uint32_t aCharIndex, char16_t aSpaceChar,
uint16_t aOrientation);
// Record the positions of specific characters that layout may need to
// detect in the textrun, even though it doesn't have an explicit copy
// of the original text. These are recorded using flag bits in the
// CompressedGlyph record; if necessary, we convert "simple" glyph records
// to "complex" ones as the Tab and Newline flags are not present in
// simple CompressedGlyph records.
void SetIsTab(uint32_t aIndex) {
EnsureComplexGlyph(aIndex).SetIsTab();
}
void SetIsNewline(uint32_t aIndex) {
EnsureComplexGlyph(aIndex).SetIsNewline();
}
/**
* Prefetch all the glyph extents needed to ensure that Measure calls
* on this textrun not requesting tight boundingBoxes will succeed. Note
* that some glyph extents might not be fetched due to OOM or other
* errors.
*/
void FetchGlyphExtents(gfxContext *aRefContext);
uint32_t CountMissingGlyphs();
const GlyphRun *GetGlyphRuns(uint32_t *aNumGlyphRuns) {
*aNumGlyphRuns = mGlyphRuns.Length();
return mGlyphRuns.Elements();
}
// Returns the index of the GlyphRun containing the given offset.
// Returns mGlyphRuns.Length() when aOffset is mCharacterCount.
uint32_t FindFirstGlyphRunContaining(uint32_t aOffset);
// Copy glyph data from a ShapedWord into this textrun.
void CopyGlyphDataFrom(gfxShapedWord *aSource, uint32_t aStart);
// Copy glyph data for a range of characters from aSource to this
// textrun.
void CopyGlyphDataFrom(gfxTextRun *aSource, uint32_t aStart,
uint32_t aLength, uint32_t aDest);
nsExpirationState *GetExpirationState() { return &mExpirationState; }
// Tell the textrun to release its reference to its creating gfxFontGroup
// immediately, rather than on destruction. This is used for textruns
// that are actually owned by a gfxFontGroup, so that they don't keep it
// permanently alive due to a circular reference. (The caller of this is
// taking responsibility for ensuring the textrun will not outlive its
// mFontGroup.)
void ReleaseFontGroup();
struct LigatureData {
// textrun offsets of the start and end of the containing ligature
uint32_t mLigatureStart;
uint32_t mLigatureEnd;
// appunits advance to the start of the ligature part within the ligature;
// never includes any spacing
gfxFloat mPartAdvance;
// appunits width of the ligature part; includes before-spacing
// when the part is at the start of the ligature, and after-spacing
// when the part is as the end of the ligature
gfxFloat mPartWidth;
bool mClipBeforePart;
bool mClipAfterPart;
};
// return storage used by this run, for memory reporter;
// nsTransformedTextRun needs to override this as it holds additional data
virtual size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf)
MOZ_MUST_OVERRIDE;
virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf)
MOZ_MUST_OVERRIDE;
// Get the size, if it hasn't already been gotten, marking as it goes.
size_t MaybeSizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) {
if (mFlags & gfxTextRunFactory::TEXT_RUN_SIZE_ACCOUNTED) {
return 0;
}
mFlags |= gfxTextRunFactory::TEXT_RUN_SIZE_ACCOUNTED;
return SizeOfIncludingThis(aMallocSizeOf);
}
void ResetSizeOfAccountingFlags() {
mFlags &= ~gfxTextRunFactory::TEXT_RUN_SIZE_ACCOUNTED;
}
// shaping state - for some font features, fallback is required that
// affects the entire run. for example, fallback for one script/font
// portion of a textrun requires fallback to be applied to the entire run
enum ShapingState {
eShapingState_Normal, // default state
eShapingState_ShapingWithFeature, // have shaped with feature
eShapingState_ShapingWithFallback, // have shaped with fallback
eShapingState_Aborted, // abort initial iteration
eShapingState_ForceFallbackFeature // redo with fallback forced on
};
ShapingState GetShapingState() const { return mShapingState; }
void SetShapingState(ShapingState aShapingState) {
mShapingState = aShapingState;
}
int32_t GetAdvanceForGlyph(uint32_t aIndex)
{
const CompressedGlyph& glyphData = mCharacterGlyphs[aIndex];
if (glyphData.IsSimpleGlyph()) {
return glyphData.GetSimpleAdvance();
}
uint32_t glyphCount = glyphData.GetGlyphCount();
if (!glyphCount) {
return 0;
}
const DetailedGlyph* details = GetDetailedGlyphs(aIndex);
int32_t advance = 0;
for (uint32_t j = 0; j < glyphCount; ++j, ++details) {
advance += details->mAdvance;
}
return advance;
}
#ifdef DEBUG
void Dump(FILE* aOutput);
#endif
protected:
/**
* Create a textrun, and set its mCharacterGlyphs to point immediately
* after the base object; this is ONLY used in conjunction with placement
* new, after allocating a block large enough for the glyph records to
* follow the base textrun object.
*/
gfxTextRun(const gfxTextRunFactory::Parameters *aParams,
uint32_t aLength, gfxFontGroup *aFontGroup, uint32_t aFlags);
/**
* Helper for the Create() factory method to allocate the required
* glyph storage for a textrun object with the basic size aSize,
* plus room for aLength glyph records.
*/
static void* AllocateStorageForTextRun(size_t aSize, uint32_t aLength);
// Pointer to the array of CompressedGlyph records; must be initialized
// when the object is constructed.
CompressedGlyph *mCharacterGlyphs;
private:
// **** general helpers ****
// Get the total advance for a range of glyphs.
int32_t GetAdvanceForGlyphs(uint32_t aStart, uint32_t aEnd);
// Spacing for characters outside the range aSpacingStart/aSpacingEnd
// is assumed to be zero; such characters are not passed to aProvider.
// This is useful to protect aProvider from being passed character indices
// it is not currently able to handle.
bool GetAdjustedSpacingArray(uint32_t aStart, uint32_t aEnd,
PropertyProvider *aProvider,
uint32_t aSpacingStart, uint32_t aSpacingEnd,
nsTArray<PropertyProvider::Spacing> *aSpacing);
CompressedGlyph& EnsureComplexGlyph(uint32_t aIndex)
{
gfxShapedText::EnsureComplexGlyph(aIndex, mCharacterGlyphs[aIndex]);
return mCharacterGlyphs[aIndex];
}
// **** ligature helpers ****
// (Platforms do the actual ligaturization, but we need to do a bunch of stuff
// to handle requests that begin or end inside a ligature)
// if aProvider is null then mBeforeSpacing and mAfterSpacing are set to zero
LigatureData ComputeLigatureData(uint32_t aPartStart, uint32_t aPartEnd,
PropertyProvider *aProvider);
gfxFloat ComputePartialLigatureWidth(uint32_t aPartStart, uint32_t aPartEnd,
PropertyProvider *aProvider);
void DrawPartialLigature(gfxFont *aFont, uint32_t aStart, uint32_t aEnd,
gfxPoint *aPt, PropertyProvider *aProvider,
TextRunDrawParams& aParams, uint16_t aOrientation);
// Advance aStart to the start of the nearest ligature; back up aEnd
// to the nearest ligature end; may result in *aStart == *aEnd
void ShrinkToLigatureBoundaries(uint32_t *aStart, uint32_t *aEnd);
// result in appunits
gfxFloat GetPartialLigatureWidth(uint32_t aStart, uint32_t aEnd, PropertyProvider *aProvider);
void AccumulatePartialLigatureMetrics(gfxFont *aFont,
uint32_t aStart, uint32_t aEnd,
gfxFont::BoundingBoxType aBoundingBoxType,
gfxContext *aRefContext,
PropertyProvider *aProvider,
uint16_t aOrientation,
Metrics *aMetrics);
// **** measurement helper ****
void AccumulateMetricsForRun(gfxFont *aFont, uint32_t aStart, uint32_t aEnd,
gfxFont::BoundingBoxType aBoundingBoxType,
gfxContext *aRefContext,
PropertyProvider *aProvider,
uint32_t aSpacingStart, uint32_t aSpacingEnd,
uint16_t aOrientation,
Metrics *aMetrics);
// **** drawing helper ****
void DrawGlyphs(gfxFont *aFont, uint32_t aStart, uint32_t aEnd,
gfxPoint *aPt, PropertyProvider *aProvider,
uint32_t aSpacingStart, uint32_t aSpacingEnd,
TextRunDrawParams& aParams, uint16_t aOrientation);
// XXX this should be changed to a GlyphRun plus a maybe-null GlyphRun*,
// for smaller size especially in the super-common one-glyphrun case
nsAutoTArray<GlyphRun,1> mGlyphRuns;
void *mUserData;
gfxFontGroup *mFontGroup; // addrefed on creation, but our reference
// may be released by ReleaseFontGroup()
gfxSkipChars mSkipChars;
nsExpirationState mExpirationState;
bool mSkipDrawing; // true if the font group we used had a user font
// download that's in progress, so we should hide text
// until the download completes (or timeout fires)
bool mReleasedFontGroup; // we already called NS_RELEASE on
// mFontGroup, so don't do it again
// shaping state for handling variant fallback features
// such as subscript/superscript variant glyphs
ShapingState mShapingState;
};
class gfxFontGroup : public gfxTextRunFactory {
public:
static void Shutdown(); // platform must call this to release the languageAtomService
gfxFontGroup(const mozilla::FontFamilyList& aFontFamilyList,
const gfxFontStyle* aStyle,
gfxTextPerfMetrics* aTextPerf,
gfxUserFontSet* aUserFontSet,
gfxFloat aDevToCssSize);
virtual ~gfxFontGroup();
// Returns first valid font in the fontlist or default font.
// Initiates userfont loads if userfont not loaded
virtual gfxFont* GetFirstValidFont(uint32_t aCh = 0x20);
// Returns the first font in the font-group that has an OpenType MATH table,
// or null if no such font is available. The GetMathConstant methods may be
// called on the returned font.
gfxFont *GetFirstMathFont();
const gfxFontStyle *GetStyle() const { return &mStyle; }
virtual gfxFontGroup *Copy(const gfxFontStyle *aStyle);
/**
* The listed characters should be treated as invisible and zero-width
* when creating textruns.
*/
static bool IsInvalidChar(uint8_t ch);
static bool IsInvalidChar(char16_t ch);
/**
* Make a textrun for a given string.
* If aText is not persistent (aFlags & TEXT_IS_PERSISTENT), the
* textrun will copy it.
* This calls FetchGlyphExtents on the textrun.
*/
virtual gfxTextRun *MakeTextRun(const char16_t *aString, uint32_t aLength,
const Parameters *aParams, uint32_t aFlags,
gfxMissingFontRecorder *aMFR);
/**
* Make a textrun for a given string.
* If aText is not persistent (aFlags & TEXT_IS_PERSISTENT), the
* textrun will copy it.
* This calls FetchGlyphExtents on the textrun.
*/
virtual gfxTextRun *MakeTextRun(const uint8_t *aString, uint32_t aLength,
const Parameters *aParams, uint32_t aFlags,
gfxMissingFontRecorder *aMFR);
/**
* Textrun creation helper for clients that don't want to pass
* a full Parameters record.
*/
template<typename T>
gfxTextRun *MakeTextRun(const T *aString, uint32_t aLength,
gfxContext *aRefContext,
int32_t aAppUnitsPerDevUnit,
uint32_t aFlags,
gfxMissingFontRecorder *aMFR)
{
gfxTextRunFactory::Parameters params = {
aRefContext, nullptr, nullptr, nullptr, 0, aAppUnitsPerDevUnit
};
return MakeTextRun(aString, aLength, &params, aFlags, aMFR);
}
/**
* Get the (possibly-cached) width of the hyphen character.
* The aCtx and aAppUnitsPerDevUnit parameters will be used only if
* needed to initialize the cached hyphen width; otherwise they are
* ignored.
*/
gfxFloat GetHyphenWidth(gfxTextRun::PropertyProvider* aProvider);
/**
* Make a text run representing a single hyphen character.
* This will use U+2010 HYPHEN if available in the first font,
* otherwise fall back to U+002D HYPHEN-MINUS.
* The caller is responsible for deleting the returned text run
* when no longer required.
*/
gfxTextRun *MakeHyphenTextRun(gfxContext *aCtx,
uint32_t aAppUnitsPerDevUnit);
/**
* Check whether a given font (specified by its gfxFontEntry)
* is already in the fontgroup's list of actual fonts
*/
bool HasFont(const gfxFontEntry *aFontEntry);
// This returns the preferred underline for this font group.
// Some CJK fonts have wrong underline offset in its metrics.
// If this group has such "bad" font, each platform's gfxFontGroup
// initialized mUnderlineOffset. The value should be lower value of
// first font's metrics and the bad font's metrics. Otherwise, this
// returns from first font's metrics.
enum { UNDERLINE_OFFSET_NOT_SET = INT16_MAX };
virtual gfxFloat GetUnderlineOffset();
virtual already_AddRefed<gfxFont>
FindFontForChar(uint32_t ch, uint32_t prevCh, uint32_t aNextCh,
int32_t aRunScript, gfxFont *aPrevMatchedFont,
uint8_t *aMatchType);
gfxUserFontSet* GetUserFontSet();
// With downloadable fonts, the composition of the font group can change as fonts are downloaded
// for each change in state of the user font set, the generation value is bumped to avoid picking up
// previously created text runs in the text run word cache. For font groups based on stylesheets
// with no @font-face rule, this always returns 0.
uint64_t GetGeneration();
// generation of the latest fontset rebuild, 0 when no fontset present
uint64_t GetRebuildGeneration();
// used when logging text performance
gfxTextPerfMetrics *GetTextPerfMetrics() { return mTextPerf; }
// This will call UpdateUserFonts() if the user font set is changed.
void SetUserFontSet(gfxUserFontSet *aUserFontSet);
// If there is a user font set, check to see whether the font list or any
// caches need updating.
virtual void UpdateUserFonts();
// search for a specific userfont in the list of fonts
bool ContainsUserFont(const gfxUserFontEntry* aUserFont);
bool ShouldSkipDrawing() const {
return mSkipDrawing;
}
class LazyReferenceContextGetter {
public:
virtual already_AddRefed<gfxContext> GetRefContext() = 0;
};
// The gfxFontGroup keeps ownership of this textrun.
// It is only guaranteed to exist until the next call to GetEllipsisTextRun
// (which might use a different appUnitsPerDev value or flags) for the font
// group, or until UpdateUserFonts is called, or the fontgroup is destroyed.
// Get it/use it/forget it :) - don't keep a reference that might go stale.
gfxTextRun* GetEllipsisTextRun(int32_t aAppUnitsPerDevPixel, uint32_t aFlags,
LazyReferenceContextGetter& aRefContextGetter);
protected:
// search through pref fonts for a character, return nullptr if no matching pref font
already_AddRefed<gfxFont> WhichPrefFontSupportsChar(uint32_t aCh);
already_AddRefed<gfxFont>
WhichSystemFontSupportsChar(uint32_t aCh, uint32_t aNextCh,
int32_t aRunScript);
template<typename T>
void ComputeRanges(nsTArray<gfxTextRange>& mRanges,
const T *aString, uint32_t aLength,
int32_t aRunScript, uint16_t aOrientation);
class FamilyFace {
public:
FamilyFace() : mFamily(nullptr), mFontEntry(nullptr),
mNeedsBold(false), mFontCreated(false),
mLoading(false), mInvalid(false),
mCheckForFallbackFaces(false)
{ }
FamilyFace(gfxFontFamily* aFamily, gfxFont* aFont)
: mFamily(aFamily), mNeedsBold(false), mFontCreated(true),
mLoading(false), mInvalid(false), mCheckForFallbackFaces(false)
{
NS_ASSERTION(aFont, "font pointer must not be null");
NS_ASSERTION(!aFamily ||
aFamily->ContainsFace(aFont->GetFontEntry()),
"font is not a member of the given family");
mFont = aFont;
NS_ADDREF(aFont);
}
FamilyFace(gfxFontFamily* aFamily, gfxFontEntry* aFontEntry,
bool aNeedsBold)
: mFamily(aFamily), mNeedsBold(aNeedsBold), mFontCreated(false),
mLoading(false), mInvalid(false), mCheckForFallbackFaces(false)
{
NS_ASSERTION(aFontEntry, "font entry pointer must not be null");
NS_ASSERTION(!aFamily ||
aFamily->ContainsFace(aFontEntry),
"font is not a member of the given family");
mFontEntry = aFontEntry;
NS_ADDREF(aFontEntry);
}
FamilyFace(const FamilyFace& aOtherFamilyFace)
: mFamily(aOtherFamilyFace.mFamily),
mNeedsBold(aOtherFamilyFace.mNeedsBold),
mFontCreated(aOtherFamilyFace.mFontCreated),
mLoading(aOtherFamilyFace.mLoading),
mInvalid(aOtherFamilyFace.mInvalid),
mCheckForFallbackFaces(aOtherFamilyFace.mCheckForFallbackFaces)
{
if (mFontCreated) {
mFont = aOtherFamilyFace.mFont;
NS_ADDREF(mFont);
} else {
mFontEntry = aOtherFamilyFace.mFontEntry;
NS_IF_ADDREF(mFontEntry);
}
}
~FamilyFace()
{
if (mFontCreated) {
NS_RELEASE(mFont);
} else {
NS_IF_RELEASE(mFontEntry);
}
}
FamilyFace& operator=(const FamilyFace& aOther)
{
if (mFontCreated) {
NS_RELEASE(mFont);
} else {
NS_IF_RELEASE(mFontEntry);
}
mFamily = aOther.mFamily;
mNeedsBold = aOther.mNeedsBold;
mFontCreated = aOther.mFontCreated;
mLoading = aOther.mLoading;
mInvalid = aOther.mInvalid;
if (mFontCreated) {
mFont = aOther.mFont;
NS_ADDREF(mFont);
} else {
mFontEntry = aOther.mFontEntry;
NS_IF_ADDREF(mFontEntry);
}
return *this;
}
gfxFontFamily* Family() const { return mFamily.get(); }
gfxFont* Font() const {
return mFontCreated ? mFont : nullptr;
}
gfxFontEntry* FontEntry() const {
return mFontCreated ? mFont->GetFontEntry() : mFontEntry;
}
bool NeedsBold() const { return mNeedsBold; }
bool IsUserFontContainer() const {
return FontEntry()->mIsUserFontContainer;
}
bool IsLoading() const { return mLoading; }
bool IsInvalid() const { return mInvalid; }
void CheckState(bool& aSkipDrawing);
void SetLoading(bool aIsLoading) { mLoading = aIsLoading; }
void SetInvalid() { mInvalid = true; }
bool CheckForFallbackFaces() const { return mCheckForFallbackFaces; }
void SetCheckForFallbackFaces() { mCheckForFallbackFaces = true; }
void SetFont(gfxFont* aFont)
{
NS_ASSERTION(aFont, "font pointer must not be null");
NS_ADDREF(aFont);
if (mFontCreated) {
NS_RELEASE(mFont);
} else {
NS_IF_RELEASE(mFontEntry);
}
mFont = aFont;
mFontCreated = true;
mLoading = false;
}
bool EqualsUserFont(const gfxUserFontEntry* aUserFont) const;
private:
RefPtr<gfxFontFamily> mFamily;
// either a font or a font entry exists
union {
gfxFont* mFont;
gfxFontEntry* mFontEntry;
};
bool mNeedsBold : 1;
bool mFontCreated : 1;
bool mLoading : 1;
bool mInvalid : 1;
bool mCheckForFallbackFaces : 1;
};
// List of font families, either named or generic.
// Generic names map to system pref fonts based on language.
mozilla::FontFamilyList mFamilyList;
// Fontlist containing a font entry for each family found. gfxFont objects
// are created as needed and userfont loads are initiated when needed.
// Code should be careful about addressing this array directly.
nsTArray<FamilyFace> mFonts;
RefPtr<gfxFont> mDefaultFont;
gfxFontStyle mStyle;
gfxFloat mUnderlineOffset;
gfxFloat mHyphenWidth;
gfxFloat mDevToCssSize;
RefPtr<gfxUserFontSet> mUserFontSet;
uint64_t mCurrGeneration; // track the current user font set generation, rebuild font list if needed
gfxTextPerfMetrics *mTextPerf;
// Cache a textrun representing an ellipsis (useful for CSS text-overflow)
// at a specific appUnitsPerDevPixel size and orientation
nsAutoPtr<gfxTextRun> mCachedEllipsisTextRun;
// cache the most recent pref font to avoid general pref font lookup
RefPtr<gfxFontFamily> mLastPrefFamily;
RefPtr<gfxFont> mLastPrefFont;
eFontPrefLang mLastPrefLang; // lang group for last pref font
eFontPrefLang mPageLang;
bool mLastPrefFirstFont; // is this the first font in the list of pref fonts for this lang group?
bool mSkipDrawing; // hide text while waiting for a font
// download to complete (or fallback
// timer to fire)
// xxx - gfxPangoFontGroup skips UpdateUserFonts
bool mSkipUpdateUserFonts;
/**
* Textrun creation short-cuts for special cases where we don't need to
* call a font shaper to generate glyphs.
*/
gfxTextRun *MakeEmptyTextRun(const Parameters *aParams, uint32_t aFlags);
gfxTextRun *MakeSpaceTextRun(const Parameters *aParams, uint32_t aFlags);
gfxTextRun *MakeBlankTextRun(uint32_t aLength,
const Parameters *aParams, uint32_t aFlags);
// Initialize the list of fonts
void BuildFontList();
// Get the font at index i within the fontlist.
// Will initiate userfont load if not already loaded.
// May return null if userfont not loaded or if font invalid
virtual gfxFont* GetFontAt(int32_t i, uint32_t aCh = 0x20);
// Whether there's a font loading for a given family in the fontlist
// for a given character
bool FontLoadingForFamily(gfxFontFamily* aFamily, uint32_t aCh) const;
// will always return a font or force a shutdown
gfxFont* GetDefaultFont();
// Init this font group's font metrics. If there no bad fonts, you don't need to call this.
// But if there are one or more bad fonts which have bad underline offset,
// you should call this with the *first* bad font.
void InitMetricsForBadFont(gfxFont* aBadFont);
// Set up the textrun glyphs for an entire text run:
// find script runs, and then call InitScriptRun for each
template<typename T>
void InitTextRun(gfxContext *aContext,
gfxTextRun *aTextRun,
const T *aString,
uint32_t aLength,
gfxMissingFontRecorder *aMFR);
// InitTextRun helper to handle a single script run, by finding font ranges
// and calling each font's InitTextRun() as appropriate
template<typename T>
void InitScriptRun(gfxContext *aContext,
gfxTextRun *aTextRun,
const T *aString,
uint32_t aScriptRunStart,
uint32_t aScriptRunEnd,
int32_t aRunScript,
gfxMissingFontRecorder *aMFR);
// Helper for font-matching:
// When matching the italic case, allow use of the regular face
// if it supports a character but the italic one doesn't.
// Return null if regular face doesn't support aCh
already_AddRefed<gfxFont>
FindNonItalicFaceForChar(gfxFontFamily* aFamily, uint32_t aCh);
// search all faces in a family for a fallback in cases where it's unclear
// whether the family might have a font for a given character
already_AddRefed<gfxFont>
FindFallbackFaceForChar(gfxFontFamily* aFamily, uint32_t aCh,
int32_t aRunScript);
// helper methods for looking up fonts
// lookup and add a font with a given name (i.e. *not* a generic!)
void AddPlatformFont(const nsAString& aName,
nsTArray<gfxFontFamily*>& aFamilyList);
// do style selection and add entries to list
void AddFamilyToFontList(gfxFontFamily* aFamily);
static nsILanguageAtomService* gLangService;
};
// A "missing font recorder" is to be used during text-run creation to keep
// a record of any scripts encountered for which font coverage was lacking;
// when Flush() is called, it sends a notification that front-end code can use
// to download fonts on demand (or whatever else it wants to do).
#define GFX_MISSING_FONTS_NOTIFY_PREF "gfx.missing_fonts.notify"
class gfxMissingFontRecorder {
public:
gfxMissingFontRecorder()
{
MOZ_COUNT_CTOR(gfxMissingFontRecorder);
memset(&mMissingFonts, 0, sizeof(mMissingFonts));
}
~gfxMissingFontRecorder()
{
#ifdef DEBUG
for (uint32_t i = 0; i < kNumScriptBitsWords; i++) {
NS_ASSERTION(mMissingFonts[i] == 0,
"failed to flush the missing-font recorder");
}
#endif
MOZ_COUNT_DTOR(gfxMissingFontRecorder);
}
// record this script code in our mMissingFonts bitset
void RecordScript(int32_t aScriptCode)
{
mMissingFonts[uint32_t(aScriptCode) >> 5] |=
(1 << (uint32_t(aScriptCode) & 0x1f));
}
// send a notification of any missing-scripts that have been
// recorded, and clear the mMissingFonts set for re-use
void Flush();
// forget any missing-scripts that have been recorded up to now;
// called before discarding a recorder we no longer care about
void Clear()
{
memset(&mMissingFonts, 0, sizeof(mMissingFonts));
}
private:
// Number of 32-bit words needed for the missing-script flags
static const uint32_t kNumScriptBitsWords =
((MOZ_NUM_SCRIPT_CODES + 31) / 32);
uint32_t mMissingFonts[kNumScriptBitsWords];
};
#endif
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