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pjs/gfx/thebes/public/gfxFont.h

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/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* ***** 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 Foundation code.
*
* The Initial Developer of the Original Code is Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2005
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Stuart Parmenter <stuart@mozilla.com>
* Masayuki Nakano <masayuki@d-toybox.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either 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 ***** */
#ifndef GFX_FONT_H
#define GFX_FONT_H
#include "prtypes.h"
#include "gfxTypes.h"
#include "nsString.h"
#include "gfxPoint.h"
#include "nsTArray.h"
#include "nsTHashtable.h"
#include "nsHashKeys.h"
#include "gfxSkipChars.h"
#include "gfxRect.h"
#include "nsExpirationTracker.h"
#include "nsMathUtils.h"
#include "nsBidiUtils.h"
#ifdef DEBUG
#include <stdio.h>
#endif
class gfxContext;
class gfxTextRun;
class nsIAtom;
class gfxFont;
class gfxFontGroup;
#define FONT_STYLE_NORMAL 0
#define FONT_STYLE_ITALIC 1
#define FONT_STYLE_OBLIQUE 2
#define FONT_WEIGHT_NORMAL 400
#define FONT_WEIGHT_BOLD 700
#define FONT_MAX_SIZE 2000.0
struct THEBES_API gfxFontStyle {
gfxFontStyle();
gfxFontStyle(PRUint8 aStyle, PRUint16 aWeight, gfxFloat aSize,
const nsACString& aLangGroup,
float aSizeAdjust, PRPackedBool aSystemFont,
PRPackedBool aFamilyNameQuirks);
gfxFontStyle(const gfxFontStyle& aStyle);
// The style of font (normal, italic, oblique)
PRUint8 style : 7;
// Say that this font is a system font and therefore does not
// require certain fixup that we do for fonts from untrusted
// sources.
PRPackedBool systemFont : 1;
// True if the character set quirks (for treatment of "Symbol",
// "Wingdings", etc.) should be applied.
PRPackedBool familyNameQuirks : 1;
// The weight of the font. 100, 200, ... 900 are the weights, and
// single integer offsets request the next bolder/lighter font
// available. For example, for a font available in weights 200,
// 400, 700, and 900, a weight of 898 should lead to the weight 400
// font being used, since it is two weights lighter than 900.
PRUint16 weight;
// The logical size of the font, in pixels
gfxFloat size;
// the language group
nsCString langGroup;
// The aspect-value (ie., the ratio actualsize:actualxheight) that any
// actual physical font created from this font structure must have when
// rendering or measuring a string. A value of 0 means no adjustment
// needs to be done.
float sizeAdjust;
// Return the final adjusted font size for the given aspect ratio.
// Not meant to be called when sizeAdjust = 0.
gfxFloat GetAdjustedSize(gfxFloat aspect) const {
NS_ASSERTION(sizeAdjust != 0.0, "Not meant to be called when sizeAdjust = 0");
gfxFloat adjustedSize = PR_MAX(NS_round(size*(sizeAdjust/aspect)), 1.0);
return PR_MIN(adjustedSize, FONT_MAX_SIZE);
}
PLDHashNumber Hash() const {
return ((style + (systemFont << 7) + (familyNameQuirks << 8) +
(weight << 9)) + PRUint32(size*1000) + PRUint32(sizeAdjust*1000)) ^
HashString(langGroup);
}
void ComputeWeightAndOffset(PRInt8 *outBaseWeight,
PRInt8 *outOffset) const;
PRBool Equals(const gfxFontStyle& other) const {
return (size == other.size) &&
(style == other.style) &&
(systemFont == other.systemFont) &&
(familyNameQuirks == other.familyNameQuirks) &&
(weight == other.weight) &&
(langGroup.Equals(other.langGroup)) &&
(sizeAdjust == other.sizeAdjust);
}
};
/**
* Font cache design:
*
* The mFonts hashtable contains most fonts, indexed by (name, style).
* It does not add a reference to the fonts it contains.
* When a font's refcount decreases to zero, instead of deleting it we
* add it to our expiration tracker.
* The expiration tracker tracks fonts with zero refcount. After a certain
* period of time, such fonts expire and are deleted.
*
* We're using 3 generations with a ten-second generation interval, so
* zero-refcount fonts will be deleted 20-30 seconds after their refcount
* goes to zero, if timer events fire in a timely manner.
*/
class THEBES_API gfxFontCache : public nsExpirationTracker<gfxFont,3> {
public:
enum { TIMEOUT_SECONDS = 10 };
gfxFontCache()
: nsExpirationTracker<gfxFont,3>(TIMEOUT_SECONDS*1000) { mFonts.Init(); }
~gfxFontCache() {
// Expire everything that has a zero refcount, so we don't leak them.
AgeAllGenerations();
// All fonts should be gone.
NS_WARN_IF_FALSE(mFonts.Count() == 0,
"Fonts still alive while shutting down gfxFontCache");
// Note that we have to delete everything through the expiration
// tracker, since there might be fonts not in the hashtable but in
// the tracker.
}
/*
* Get the global gfxFontCache. You must call Init() before
* calling this method --- the result will not be null.
*/
static gfxFontCache* GetCache() {
return gGlobalCache;
}
static nsresult Init();
// It's OK to call this even if Init() has not been called.
static void Shutdown();
// Look up a font in the cache. Returns an addrefed pointer, or null
// if there's nothing matching in the cache
already_AddRefed<gfxFont> Lookup(const nsAString &aName,
const gfxFontStyle *aFontGroup);
// We created a new font (presumably because Lookup returned null);
// put it in the cache. The font's refcount should be nonzero. It is
// allowable to add a new font even if there is one already in the
// cache with the same key; we'll forget about the old one.
void AddNew(gfxFont *aFont);
// The font's refcount has gone to zero; give ownership of it to
// the cache. We delete it if it's not acquired again after a certain
// amount of time.
void NotifyReleased(gfxFont *aFont);
// This gets called when the timeout has expired on a zero-refcount
// font; we just delete it.
virtual void NotifyExpired(gfxFont *aFont);
protected:
void DestroyFont(gfxFont *aFont);
static gfxFontCache *gGlobalCache;
struct Key {
const nsAString& mString;
const gfxFontStyle* mStyle;
Key(const nsAString& aString, const gfxFontStyle* aStyle)
: mString(aString), mStyle(aStyle) {}
};
class HashEntry : public PLDHashEntryHdr {
public:
typedef const Key& KeyType;
typedef const Key* KeyTypePointer;
// When constructing a new entry in the hashtable, we'll leave this
// blank. The caller of Put() will fill this in.
HashEntry(KeyTypePointer aStr) : mFont(nsnull) { }
HashEntry(const HashEntry& toCopy) : mFont(toCopy.mFont) { }
~HashEntry() { }
PRBool KeyEquals(const KeyTypePointer aKey) const;
static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
static PLDHashNumber HashKey(const KeyTypePointer aKey) {
return HashString(aKey->mString) ^ aKey->mStyle->Hash();
}
enum { ALLOW_MEMMOVE = PR_TRUE };
gfxFont* mFont;
};
nsTHashtable<HashEntry> mFonts;
};
/**
* This stores glyph bounds information for a particular gfxFont, at
* a particular appunits-per-dev-pixel ratio (because the compressed glyph
* width array is stored in appunits).
*
* We store a hashtable from glyph IDs to float bounding rects. For the
* common case where the glyph has no horizontal left bearing, and no
* y overflow above the font ascent or below the font descent, and tight
* bounding boxes are not required, we avoid storing the glyph ID in the hashtable
* and instead consult an array of 16-bit glyph XMost values (in appunits).
* This array always has an entry for the font's space glyph --- the width is
* assumed to be zero.
*/
class THEBES_API gfxGlyphExtents {
public:
gfxGlyphExtents(PRUint32 aAppUnitsPerDevUnit) :
mAppUnitsPerDevUnit(aAppUnitsPerDevUnit) {
MOZ_COUNT_CTOR(gfxGlyphExtents);
mTightGlyphExtents.Init();
}
~gfxGlyphExtents();
enum { INVALID_WIDTH = 0xFFFF };
// returns INVALID_WIDTH => not a contained glyph
// Otherwise the glyph has no before-bearing or vertical bearings,
// and the result is its width measured from the baseline origin, in
// appunits.
PRUint16 GetContainedGlyphWidthAppUnits(PRUint32 aGlyphID) const {
return mContainedGlyphWidths.Get(aGlyphID);
}
PRBool IsGlyphKnown(PRUint32 aGlyphID) const {
return mContainedGlyphWidths.Get(aGlyphID) != INVALID_WIDTH ||
mTightGlyphExtents.GetEntry(aGlyphID) != nsnull;
}
PRBool IsGlyphKnownWithTightExtents(PRUint32 aGlyphID) const {
return mTightGlyphExtents.GetEntry(aGlyphID) != nsnull;
}
// Get glyph extents; a rectangle relative to the left baseline origin
// Returns true on success. Can fail on OOM or when aContext is null
// and extents were not (successfully) prefetched.
PRBool GetTightGlyphExtentsAppUnits(gfxFont *aFont, gfxContext *aContext,
PRUint32 aGlyphID, gfxRect *aExtents);
void SetContainedGlyphWidthAppUnits(PRUint32 aGlyphID, PRUint16 aWidth) {
mContainedGlyphWidths.Set(aGlyphID, aWidth);
}
void SetTightGlyphExtents(PRUint32 aGlyphID, const gfxRect& aExtentsAppUnits);
PRUint32 GetAppUnitsPerDevUnit() { return mAppUnitsPerDevUnit; }
private:
class HashEntry : public nsUint32HashKey {
public:
// When constructing a new entry in the hashtable, we'll leave this
// blank. The caller of Put() will fill this in.
HashEntry(KeyTypePointer aPtr) : nsUint32HashKey(aPtr) {}
HashEntry(const HashEntry& toCopy) : nsUint32HashKey(toCopy) {
x = toCopy.x; y = toCopy.y; width = toCopy.width; height = toCopy.height;
}
float x, y, width, height;
};
typedef unsigned long PtrBits;
enum { BLOCK_SIZE_BITS = 7, BLOCK_SIZE = 1 << BLOCK_SIZE_BITS }; // 128-glyph blocks
class GlyphWidths {
public:
void Set(PRUint32 aIndex, PRUint16 aValue);
PRUint16 Get(PRUint32 aIndex) const {
PRUint32 block = aIndex >> BLOCK_SIZE_BITS;
if (block >= mBlocks.Length())
return INVALID_WIDTH;
PtrBits bits = mBlocks[block];
if (!bits)
return INVALID_WIDTH;
PRUint32 indexInBlock = aIndex & (BLOCK_SIZE - 1);
if (bits & 0x1) {
if (GetGlyphOffset(bits) != indexInBlock)
return INVALID_WIDTH;
return GetWidth(bits);
}
PRUint16 *widths = reinterpret_cast<PRUint16 *>(bits);
return widths[indexInBlock];
}
#ifdef DEBUG
PRUint32 ComputeSize();
#endif
~GlyphWidths();
private:
static PRUint32 GetGlyphOffset(PtrBits aBits) {
NS_ASSERTION(aBits & 0x1, "This is really a pointer...");
return (aBits >> 1) & ((1 << BLOCK_SIZE_BITS) - 1);
}
static PRUint32 GetWidth(PtrBits aBits) {
NS_ASSERTION(aBits & 0x1, "This is really a pointer...");
return aBits >> (1 + BLOCK_SIZE_BITS);
}
static PtrBits MakeSingle(PRUint32 aGlyphOffset, PRUint16 aWidth) {
return (aWidth << (1 + BLOCK_SIZE_BITS)) + (aGlyphOffset << 1) + 1;
}
nsTArray<PtrBits> mBlocks;
};
GlyphWidths mContainedGlyphWidths;
nsTHashtable<HashEntry> mTightGlyphExtents;
PRUint32 mAppUnitsPerDevUnit;
};
/* a SPECIFIC single font family */
class THEBES_API gfxFont {
public:
nsrefcnt AddRef(void) {
NS_PRECONDITION(PRInt32(mRefCnt) >= 0, "illegal refcnt");
if (mExpirationState.IsTracked()) {
gfxFontCache::GetCache()->RemoveObject(this);
}
++mRefCnt;
NS_LOG_ADDREF(this, mRefCnt, "gfxFont", sizeof(*this));
return mRefCnt;
}
nsrefcnt Release(void) {
NS_PRECONDITION(0 != mRefCnt, "dup release");
--mRefCnt;
NS_LOG_RELEASE(this, mRefCnt, "gfxFont");
if (mRefCnt == 0) {
// Don't delete just yet; return the object to the cache for
// possibly recycling within some time limit
gfxFontCache::GetCache()->NotifyReleased(this);
return 0;
}
return mRefCnt;
}
PRInt32 GetRefCount() { return mRefCnt; }
protected:
nsAutoRefCnt mRefCnt;
public:
gfxFont(const nsAString &aName, const gfxFontStyle *aFontGroup);
virtual ~gfxFont();
const nsString& GetName() const { return mName; }
const gfxFontStyle *GetStyle() const { return &mStyle; }
virtual nsString GetUniqueName() = 0;
// Font metrics
struct Metrics {
gfxFloat xHeight;
gfxFloat superscriptOffset;
gfxFloat subscriptOffset;
gfxFloat strikeoutSize;
gfxFloat strikeoutOffset;
gfxFloat underlineSize;
gfxFloat underlineOffset;
gfxFloat height;
gfxFloat internalLeading;
gfxFloat externalLeading;
gfxFloat emHeight;
gfxFloat emAscent;
gfxFloat emDescent;
gfxFloat maxHeight;
gfxFloat maxAscent;
gfxFloat maxDescent;
gfxFloat maxAdvance;
gfxFloat aveCharWidth;
gfxFloat spaceWidth;
};
virtual const gfxFont::Metrics& GetMetrics() = 0;
/**
* We let layout specify spacing on either side of any
* character. We need to specify both before and after
* spacing so that substring measurement can do the right things.
* These values are in appunits. They're always an integral number of
* appunits, but we specify them in floats in case very large spacing
* values are required.
*/
struct Spacing {
gfxFloat mBefore;
gfxFloat mAfter;
};
/**
* Metrics for a particular string
*/
struct RunMetrics {
RunMetrics() {
mAdvanceWidth = mAscent = mDescent = 0.0;
mBoundingBox = gfxRect(0,0,0,0);
}
void CombineWith(const RunMetrics& aOtherOnRight) {
mAscent = PR_MAX(mAscent, aOtherOnRight.mAscent);
mDescent = PR_MAX(mDescent, aOtherOnRight.mDescent);
mBoundingBox =
mBoundingBox.Union(aOtherOnRight.mBoundingBox + gfxPoint(mAdvanceWidth, 0));
mAdvanceWidth += aOtherOnRight.mAdvanceWidth;
}
// can be negative (partly due to negative spacing).
// Advance widths should be additive: the advance width of the
// (offset1, length1) plus the advance width of (offset1 + length1,
// length2) should be the advance width of (offset1, length1 + length2)
gfxFloat mAdvanceWidth;
// For zero-width substrings, these must be zero!
gfxFloat mAscent; // always non-negative
gfxFloat mDescent; // always non-negative
// Bounding box that is guaranteed to include everything drawn.
// If aTightBoundingBox was set to true when these metrics were
// generated, this will tightly wrap the glyphs, otherwise it is
// "loose" and may be larger than the true bounding box.
// Coordinates are relative to the baseline left origin, so typically
// mBoundingBox.y == -mAscent
gfxRect mBoundingBox;
};
/**
* Draw a series of glyphs to aContext. The direction of aTextRun must
* be honoured.
* @param aStart the first character to draw
* @param aEnd draw characters up to here
* @param aBaselineOrigin the baseline origin; the left end of the baseline
* for LTR textruns, the right end of the baseline for RTL textruns. On return,
* this should be updated to the other end of the baseline. In application
* units, really!
* @param aSpacing spacing to insert before and after characters (for RTL
* glyphs, before-spacing is inserted to the right of characters). There
* are aEnd - aStart elements in this array, unless it's null to indicate
* that there is no spacing.
* @param aDrawToPath when true, add the glyph outlines to the current path
* instead of drawing the glyphs
*
* Callers guarantee:
* -- aStart and aEnd are aligned to cluster and ligature boundaries
* -- all glyphs use this font
*
* The default implementation builds a cairo glyph array and
* calls cairo_show_glyphs or cairo_glyph_path.
*/
virtual void Draw(gfxTextRun *aTextRun, PRUint32 aStart, PRUint32 aEnd,
gfxContext *aContext, PRBool aDrawToPath, gfxPoint *aBaselineOrigin,
Spacing *aSpacing);
/**
* Measure a run of characters. See gfxTextRun::Metrics.
* @param aTight if false, then return the union of the glyph extents
* with the font-box for the characters (the rectangle with x=0,width=
* the advance width for the character run,y=-(font ascent), and height=
* font ascent + font descent). Otherwise, we must return as tight as possible
* an approximation to the area actually painted by glyphs.
* @param aContextForTightBoundingBox when aTight is true, this must
* be non-null.
* @param aSpacing spacing to insert before and after glyphs. The bounding box
* need not include the spacing itself, but the spacing affects the glyph
* positions. null if there is no spacing.
*
* Callers guarantee:
* -- aStart and aEnd are aligned to cluster and ligature boundaries
* -- all glyphs use this font
*
* The default implementation just uses font metrics and aTextRun's
* advances, and assumes no characters fall outside the font box. In
* general this is insufficient, because that assumption is not always true.
*/
virtual RunMetrics Measure(gfxTextRun *aTextRun,
PRUint32 aStart, PRUint32 aEnd,
PRBool aTightBoundingBox,
gfxContext *aContextForTightBoundingBox,
Spacing *aSpacing);
/**
* Line breaks have been changed at the beginning and/or end of a substring
* of the text. Reshaping may be required; glyph updating is permitted.
* @return true if anything was changed, false otherwise
*/
PRBool NotifyLineBreaksChanged(gfxTextRun *aTextRun,
PRUint32 aStart, PRUint32 aLength)
{ return PR_FALSE; }
// Expiration tracking
nsExpirationState *GetExpirationState() { return &mExpirationState; }
// Get the glyphID of a space
virtual PRUint32 GetSpaceGlyph() = 0;
gfxGlyphExtents *GetOrCreateGlyphExtents(PRUint32 aAppUnitsPerDevUnit);
// You need to call SetupCairoFont on the aCR just before calling this
virtual void SetupGlyphExtents(gfxContext *aContext, PRUint32 aGlyphID,
PRBool aNeedTight, gfxGlyphExtents *aExtents);
// This is called by the default Draw() implementation above.
virtual PRBool SetupCairoFont(gfxContext *aContext) = 0;
protected:
// The family name of the font
nsString mName;
nsExpirationState mExpirationState;
gfxFontStyle mStyle;
nsAutoTArray<gfxGlyphExtents*,1> mGlyphExtentsArray;
// some fonts have bad metrics, this method sanitize them.
// if this font has bad underline offset, aIsBadUnderlineFont should be true.
void SanitizeMetrics(gfxFont::Metrics *aMetrics, PRBool aIsBadUnderlineFont);
};
class THEBES_API gfxTextRunFactory {
THEBES_INLINE_DECL_REFCOUNTING(gfxTextRunFactory)
public:
// Flags in the mask 0xFFFF0000 are reserved for textrun clients
// Flags in the mask 0x0000F000 are reserved for per-platform fonts
// Flags in the mask 0x00000FFF are set by the textrun creator.
enum {
CACHE_TEXT_FLAGS = 0xF0000000,
USER_TEXT_FLAGS = 0x0FFF0000,
PLATFORM_TEXT_FLAGS = 0x0000F000,
TEXTRUN_TEXT_FLAGS = 0x00000FFF,
SETTABLE_FLAGS = CACHE_TEXT_FLAGS | USER_TEXT_FLAGS,
/**
* When set, the text string pointer used to create the text run
* is guaranteed to be available during the lifetime of the text run.
*/
TEXT_IS_PERSISTENT = 0x0001,
/**
* When set, the text is known to be all-ASCII (< 128).
*/
TEXT_IS_ASCII = 0x0002,
/**
* When set, the text is RTL.
*/
TEXT_IS_RTL = 0x0004,
/**
* When set, spacing is enabled and the textrun needs to call GetSpacing
* on the spacing provider.
*/
TEXT_ENABLE_SPACING = 0x0008,
/**
* When set, GetSpacing can return negative spacing.
*/
TEXT_ENABLE_NEGATIVE_SPACING = 0x0010,
/**
* When set, GetHyphenationBreaks may return true for some character
* positions, otherwise it will always return false for all characters.
*/
TEXT_ENABLE_HYPHEN_BREAKS = 0x0040,
/**
* When set, the text has no characters above 255 and it is stored
* in the textrun in 8-bit format.
*/
TEXT_IS_8BIT = 0x0080,
/**
* When set, the text may have UTF16 surrogate pairs, otherwise it
* doesn't.
*/
TEXT_HAS_SURROGATES = 0x0100,
/**
* When set, the RunMetrics::mBoundingBox field will be initialized
* properly based on glyph extents, in particular, glyph extents that
* overflow the standard font-box (the box defined by the ascent, descent
* and advance width of the glyph). When not set, it may just be the
* standard font-box even if glyphs overflow.
*/
TEXT_NEED_BOUNDING_BOX = 0x0200,
/**
* When set, optional ligatures are disabled. Ligatures that are
* required for legible text should still be enabled.
*/
TEXT_DISABLE_OPTIONAL_LIGATURES = 0x0400,
/**
* When set, the textrun should favour speed of construction over
* quality. This may involve disabling ligatures and/or kerning or
* other effects.
*/
TEXT_OPTIMIZE_SPEED = 0x0800
};
/**
* This record contains all the parameters needed to initialize a textrun.
*/
struct Parameters {
// A reference context suggesting where the textrun will be rendered
gfxContext *mContext;
// Pointer to arbitrary user data (which should outlive the textrun)
void *mUserData;
// A description of which characters have been stripped from the original
// DOM string to produce the characters in the textrun. May be null
// if that information is not relevant.
gfxSkipChars *mSkipChars;
// A list of where linebreaks are currently placed in the textrun. May
// be null if mInitialBreakCount is zero.
PRUint32 *mInitialBreaks;
PRUint32 mInitialBreakCount;
// The ratio to use to convert device pixels to application layout units
PRUint32 mAppUnitsPerDevUnit;
};
virtual ~gfxTextRunFactory() {}
};
/**
* 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!
*
* gfxTextRun stores a list of zero or more glyphs for each character. For each
* glyph we store the glyph ID, the advance, and possibly an xoffset and yoffset.
* The idea is that a string is rendered by a loop that draws each glyph
* at its designated offset from the current point, then advances the current
* point by the glyph's advance in the direction of the textrun (LTR or RTL).
* Each glyph advance is always rounded to the nearest appunit; this ensures
* consistent results when dividing the text in a textrun into multiple text
* frames (frame boundaries are always aligned to appunits). We optimize
* for the case where a character has a single glyph and zero xoffset and yoffset,
* and the glyph ID and advance are in a reasonable range so we can pack all
* necessary data into 32 bits.
*
* gfxTextRun methods that measure or draw substrings will associate all the
* glyphs in a cluster with the first character of the cluster; if that character
* is in the substring, the glyphs will be measured or drawn, otherwise they
* won't.
*/
class THEBES_API gfxTextRun {
public:
// Override operator delete because we used custom allocation
void operator delete(void* aPtr);
virtual ~gfxTextRun();
typedef gfxFont::RunMetrics Metrics;
// Public textrun API for general use
PRBool IsClusterStart(PRUint32 aPos) {
NS_ASSERTION(0 <= aPos && aPos < mCharacterCount, "aPos out of range");
return mCharacterGlyphs[aPos].IsClusterStart();
}
PRBool IsLigatureGroupStart(PRUint32 aPos) {
NS_ASSERTION(0 <= aPos && aPos < mCharacterCount, "aPos out of range");
return mCharacterGlyphs[aPos].IsLigatureGroupStart();
}
PRBool CanBreakLineBefore(PRUint32 aPos) {
NS_ASSERTION(0 <= aPos && aPos < mCharacterCount, "aPos out of range");
return mCharacterGlyphs[aPos].CanBreakBefore();
}
PRUint32 GetLength() { return mCharacterCount; }
// All PRUint32 aStart, PRUint32 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 PRBool SetPotentialLineBreaks(PRUint32 aStart, PRUint32 aLength,
PRPackedBool *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(PRUint32 aStart, PRUint32 aLength,
PRPackedBool *aBreakBefore) = 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(PRUint32 aStart, PRUint32 aLength,
Spacing *aSpacing) = 0;
};
/**
* 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 aDirtyRect if non-null, drawing outside of the rectangle can be
* (but does not need to be) dropped. Note that if this is null, we cannot
* draw partial ligatures and we will assert if partial ligatures
* are detected.
* @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, nsnull) should have the same effect as
* Draw(ctx, pt, offset1, length1+length2, dirty, &provider, nsnull).
* 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, nsnull) should have the same effect as
* Draw(ctx, pt, offset1, length1+length2, dirty, &provider, nsnull).
*
* 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,
PRUint32 aStart, PRUint32 aLength,
const gfxRect *aDirtyRect,
PropertyProvider *aProvider,
gfxFloat *aAdvanceWidth);
/**
* Renders a substring to a path. 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 way that Draw above does.
*
* Glyphs should be drawn in logical content order.
*
* UNLIKE Draw above, this cannot be used to render substrings that start or
* end inside a ligature.
*/
void DrawToPath(gfxContext *aContext, gfxPoint aPt,
PRUint32 aStart, PRUint32 aLength,
PropertyProvider *aBreakProvider,
gfxFloat *aAdvanceWidth);
/**
* Computes the ReflowMetrics for a substring.
* Uses GetSpacing from aBreakProvider.
* @param aTightBoundingBox if true, we make the bounding box tight
*/
Metrics MeasureText(PRUint32 aStart, PRUint32 aLength,
PRBool aTightBoundingBox,
gfxContext *aRefContextForTightBoundingBox,
PropertyProvider *aProvider);
/**
* Computes just the advance width for a substring.
* Uses GetSpacing from aBreakProvider.
*/
gfxFloat GetAdvanceWidth(PRUint32 aStart, PRUint32 aLength,
PropertyProvider *aProvider);
/**
* 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 PRBool SetLineBreaks(PRUint32 aStart, PRUint32 aLength,
PRBool aLineBreakBefore, PRBool aLineBreakAfter,
gfxFloat *aAdvanceWidthDelta,
gfxContext *aRefContext);
/**
* 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 PR_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 aSuppressInitialBreak if true, then we assume there is no possible
* linebreak before aStart. If false, then we will check the internal
* line break opportunity state before deciding whether to return 0 as the
* character to break before.
* @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 aTightBoundingBox if true, we make the bounding box in aMetrics tight
* @param aRefContextForTightBoundingBox a reference context to get the
* tight bounding box, if aTightBoundingBox is true
* @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 PR_UINT32_MAX if no such N exists, where GetAdvanceWidth assumes
* the effect of
* SetLineBreaks(aStart, N, aLineBreakBefore, N < aMaxLength, aProvider)
*
* Note that negative advance widths are possible especially if negative
* spacing is provided.
*/
PRUint32 BreakAndMeasureText(PRUint32 aStart, PRUint32 aMaxLength,
PRBool aLineBreakBefore, gfxFloat aWidth,
PropertyProvider *aProvider,
PRBool aSuppressInitialBreak,
gfxFloat *aTrimWhitespace,
Metrics *aMetrics, PRBool aTightBoundingBox,
gfxContext *aRefContextForTightBoundingBox,
PRBool *aUsedHyphenation,
PRUint32 *aLastBreak);
/**
* 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
PRBool IsRightToLeft() const { return (mFlags & gfxTextRunFactory::TEXT_IS_RTL) != 0; }
gfxFloat GetDirection() const { return (mFlags & gfxTextRunFactory::TEXT_IS_RTL) ? -1.0 : 1.0; }
void *GetUserData() const { return mUserData; }
void SetUserData(void *aUserData) { mUserData = aUserData; }
PRUint32 GetFlags() const { return mFlags; }
void SetFlagBits(PRUint32 aFlags) {
NS_ASSERTION(!(aFlags & ~gfxTextRunFactory::SETTABLE_FLAGS),
"Only user flags should be mutable");
mFlags |= aFlags;
}
void ClearFlagBits(PRUint32 aFlags) {
NS_ASSERTION(!(aFlags & ~gfxTextRunFactory::SETTABLE_FLAGS),
"Only user flags should be mutable");
mFlags &= ~aFlags;
}
const gfxSkipChars& GetSkipChars() const { return mSkipChars; }
PRUint32 GetAppUnitsPerDevUnit() const { return mAppUnitsPerDevUnit; }
gfxFontGroup *GetFontGroup() const { return mFontGroup; }
const PRUint8 *GetText8Bit() const
{ return (mFlags & gfxTextRunFactory::TEXT_IS_8BIT) ? mText.mSingle : nsnull; }
const PRUnichar *GetTextUnicode() const
{ return (mFlags & gfxTextRunFactory::TEXT_IS_8BIT) ? nsnull : mText.mDouble; }
const void *GetTextAt(PRUint32 aIndex) {
return (mFlags & gfxTextRunFactory::TEXT_IS_8BIT)
? static_cast<const void *>(mText.mSingle + aIndex)
: static_cast<const void *>(mText.mDouble + aIndex);
}
const PRUnichar GetChar(PRUint32 i) const
{ return (mFlags & gfxTextRunFactory::TEXT_IS_8BIT) ? mText.mSingle[i] : mText.mDouble[i]; }
PRUint32 GetHashCode() const { return mHashCode; }
void SetHashCode(PRUint32 aHash) { mHashCode = aHash; }
// Call this, don't call "new gfxTextRun" directly. This does custom
// allocation and initialization
static gfxTextRun *Create(const gfxTextRunFactory::Parameters *aParams,
const void *aText, PRUint32 aLength, gfxFontGroup *aFontGroup, PRUint32 aFlags);
// Clone this textrun, according to the given parameters. This textrun's
// glyph data is copied, so the text and length must be the same as this
// textrun's. If there's a problem, return null. Actual linebreaks will
// be set as per aParams; there will be no potential linebreaks.
// If aText is not persistent (aFlags & TEXT_IS_PERSISTENT), the
// textrun will copy it.
virtual gfxTextRun *Clone(const gfxTextRunFactory::Parameters *aParams, const void *aText,
PRUint32 aLength, gfxFontGroup *aFontGroup, PRUint32 aFlags);
/**
* This class records the information associated with a character in the
* input string. It's optimized for the case where there is one glyph
* representing that character alone.
*
* A character can have zero or more associated glyphs. Each glyph
* has an advance width and an x and y offset.
* A character may be the start of a cluster.
* A character may be the start of a ligature group.
* A character can be "missing", indicating that the system is unable
* to render the character.
*
* All characters in a ligature group conceptually share all the glyphs
* associated with the characters in a group.
*/
class CompressedGlyph {
public:
CompressedGlyph() { mValue = 0; }
enum {
// Indicates that a cluster and ligature group starts at this
// character; this character has a single glyph with a reasonable
// advance and zero offsets. A "reasonable" advance
// is one that fits in the available bits (currently 14) (specified
// in appunits).
FLAG_IS_SIMPLE_GLYPH = 0x80000000U,
// Indicates that a linebreak is allowed before this character
FLAG_CAN_BREAK_BEFORE = 0x40000000U,
// The advance is stored in appunits
ADVANCE_MASK = 0x3FFF0000U,
ADVANCE_SHIFT = 16,
GLYPH_MASK = 0x0000FFFFU,
// Non-simple glyphs may or may not have glyph data in the
// corresponding mDetailedGlyphs entry. They have the following
// flag bits:
// When NOT set, indicates that this character corresponds to a
// missing glyph and should be skipped (or possibly, render the character
// Unicode value in some special way). If there are glyphs,
// the mGlyphID is actually the UTF16 character code. The bit is
// inverted so we can memset the array to zero to indicate all missing.
FLAG_NOT_MISSING = 0x01,
FLAG_NOT_CLUSTER_START = 0x02,
FLAG_NOT_LIGATURE_GROUP_START = 0x04,
FLAG_LOW_SURROGATE = 0x08,
GLYPH_COUNT_MASK = 0x00FFFF00U,
GLYPH_COUNT_SHIFT = 8
};
// "Simple glyphs" have a simple glyph ID, simple advance and their
// x and y offsets are zero. Also the glyph extents do not overflow
// the font-box defined by the font ascent, descent and glyph advance width.
// These case is optimized to avoid storing DetailedGlyphs.
// Returns true if the glyph ID aGlyph fits into the compressed representation
static PRBool IsSimpleGlyphID(PRUint32 aGlyph) {
return (aGlyph & GLYPH_MASK) == aGlyph;
}
// Returns true if the advance aAdvance fits into the compressed representation.
// aAdvance is in appunits.
static PRBool IsSimpleAdvance(PRUint32 aAdvance) {
return (aAdvance & (ADVANCE_MASK >> ADVANCE_SHIFT)) == aAdvance;
}
PRBool IsSimpleGlyph() const { return (mValue & FLAG_IS_SIMPLE_GLYPH) != 0; }
PRUint32 GetSimpleAdvance() const { return (mValue & ADVANCE_MASK) >> ADVANCE_SHIFT; }
PRUint32 GetSimpleGlyph() const { return mValue & GLYPH_MASK; }
PRBool IsMissing() const { return (mValue & (FLAG_NOT_MISSING|FLAG_IS_SIMPLE_GLYPH)) == 0; }
PRBool IsLowSurrogate() const {
return (mValue & (FLAG_LOW_SURROGATE|FLAG_IS_SIMPLE_GLYPH)) == FLAG_LOW_SURROGATE;
}
PRBool IsClusterStart() const {
return (mValue & FLAG_IS_SIMPLE_GLYPH) || !(mValue & FLAG_NOT_CLUSTER_START);
}
PRBool IsLigatureGroupStart() const {
return (mValue & FLAG_IS_SIMPLE_GLYPH) || !(mValue & FLAG_NOT_LIGATURE_GROUP_START);
}
PRBool CanBreakBefore() const { return (mValue & FLAG_CAN_BREAK_BEFORE) != 0; }
// Returns FLAG_CAN_BREAK_BEFORE if the setting changed, 0 otherwise
PRUint32 SetCanBreakBefore(PRBool aCanBreakBefore) {
NS_ASSERTION(aCanBreakBefore == PR_FALSE || aCanBreakBefore == PR_TRUE,
"Bogus break-before value!");
PRUint32 breakMask = aCanBreakBefore*FLAG_CAN_BREAK_BEFORE;
PRUint32 toggle = breakMask ^ (mValue & FLAG_CAN_BREAK_BEFORE);
mValue ^= toggle;
return toggle;
}
CompressedGlyph& SetSimpleGlyph(PRUint32 aAdvanceAppUnits, PRUint32 aGlyph) {
NS_ASSERTION(IsSimpleAdvance(aAdvanceAppUnits), "Advance overflow");
NS_ASSERTION(IsSimpleGlyphID(aGlyph), "Glyph overflow");
mValue = (mValue & FLAG_CAN_BREAK_BEFORE) | FLAG_IS_SIMPLE_GLYPH |
(aAdvanceAppUnits << ADVANCE_SHIFT) | aGlyph;
return *this;
}
CompressedGlyph& SetComplex(PRBool aClusterStart, PRBool aLigatureStart,
PRUint32 aGlyphCount) {
mValue = (mValue & FLAG_CAN_BREAK_BEFORE) | FLAG_NOT_MISSING |
(aClusterStart ? 0 : FLAG_NOT_CLUSTER_START) |
(aLigatureStart ? 0 : FLAG_NOT_LIGATURE_GROUP_START) |
(aGlyphCount << GLYPH_COUNT_SHIFT);
return *this;
}
/**
* Missing glyphs are treated as cluster and ligature group starts.
*/
CompressedGlyph& SetMissing(PRUint32 aGlyphCount) {
mValue = (mValue & FLAG_CAN_BREAK_BEFORE) |
(aGlyphCount << GLYPH_COUNT_SHIFT);
return *this;
}
/**
* Low surrogates don't have any glyphs and are not the start of
* a cluster or ligature group.
*/
CompressedGlyph& SetLowSurrogate() {
mValue = (mValue & FLAG_CAN_BREAK_BEFORE) | FLAG_NOT_MISSING |
FLAG_LOW_SURROGATE;
return *this;
}
PRUint32 GetGlyphCount() const {
NS_ASSERTION(!IsSimpleGlyph(), "Expected non-simple-glyph");
return (mValue & GLYPH_COUNT_MASK) >> GLYPH_COUNT_SHIFT;
}
private:
PRUint32 mValue;
};
/**
* When the glyphs for a character don't fit into a CompressedGlyph record
* in SimpleGlyph format, we use an array of DetailedGlyphs instead.
*/
struct DetailedGlyph {
/** The glyphID, or the Unicode character
* if this is a missing glyph */
PRUint32 mGlyphID;
/** The advance, x-offset and y-offset of the glyph, in appunits
* mAdvance is in the text direction (RTL or LTR)
* mXOffset is always from left to right
* mYOffset is always from bottom to top */
PRInt32 mAdvance;
float mXOffset, mYOffset;
};
// The text is divided into GlyphRuns as necessary
struct GlyphRun {
nsRefPtr<gfxFont> mFont; // never null
PRUint32 mCharacterOffset; // into original UTF16 string
};
class THEBES_API GlyphRunIterator {
public:
GlyphRunIterator(gfxTextRun *aTextRun, PRUint32 aStart, PRUint32 aLength)
: mTextRun(aTextRun), mStartOffset(aStart), mEndOffset(aStart + aLength) {
mNextIndex = mTextRun->FindFirstGlyphRunContaining(aStart);
}
PRBool NextRun();
GlyphRun *GetGlyphRun() { return mGlyphRun; }
PRUint32 GetStringStart() { return mStringStart; }
PRUint32 GetStringEnd() { return mStringEnd; }
private:
gfxTextRun *mTextRun;
GlyphRun *mGlyphRun;
PRUint32 mStringStart;
PRUint32 mStringEnd;
PRUint32 mNextIndex;
PRUint32 mStartOffset;
PRUint32 mEndOffset;
};
class GlyphRunOffsetComparator {
public:
PRBool Equals(const GlyphRun& a,
const GlyphRun& b) const
{
return a.mCharacterOffset == b.mCharacterOffset;
}
PRBool 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.
/**
* Record every character that is the second half of a surrogate pair.
* This should be called after creating a Unicode textrun.
*/
void RecordSurrogates(const PRUnichar *aString);
/**
* 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, PRUint32 aStartCharIndex, PRBool aForceNewRun = PR_FALSE);
void ResetGlyphRuns() { mGlyphRuns.Clear(); }
void SortGlyphRuns();
// Call the following glyph-setters during initialization or during reshaping
// only. It is OK to overwrite existing data for a character.
/**
* Set the glyph data for a character. aGlyphs may be null if aGlyph is a
* simple glyph or has no associated glyphs. If non-null the data is copied,
* the caller retains ownership.
*/
void SetSimpleGlyph(PRUint32 aCharIndex, CompressedGlyph aGlyph) {
NS_ASSERTION(aGlyph.IsSimpleGlyph(), "Should be a simple glyph here");
if (mCharacterGlyphs) {
mCharacterGlyphs[aCharIndex] = aGlyph;
}
if (mDetailedGlyphs) {
mDetailedGlyphs[aCharIndex] = nsnull;
}
}
void SetGlyphs(PRUint32 aCharIndex, CompressedGlyph aGlyph,
const DetailedGlyph *aGlyphs);
void SetMissingGlyph(PRUint32 aCharIndex, PRUint32 aUnicodeChar);
void SetSpaceGlyph(gfxFont *aFont, gfxContext *aContext, PRUint32 aCharIndex);
/**
* Prefetch all the glyph extents needed to ensure that Measure calls
* on this textrun with aTightBoundingBox false will succeed. Note
* that some glyph extents might not be fetched due to OOM or other
* errors.
*/
void FetchGlyphExtents(gfxContext *aRefContext);
// API for access to the raw glyph data, needed by gfxFont::Draw
// and gfxFont::GetBoundingBox
const CompressedGlyph *GetCharacterGlyphs() { return mCharacterGlyphs; }
const DetailedGlyph *GetDetailedGlyphs(PRUint32 aCharIndex) {
return mDetailedGlyphs ? mDetailedGlyphs[aCharIndex].get() : nsnull;
}
PRBool HasDetailedGlyphs() { return mDetailedGlyphs.get() != nsnull; }
PRUint32 CountMissingGlyphs();
const GlyphRun *GetGlyphRuns(PRUint32 *aNumGlyphRuns) {
*aNumGlyphRuns = mGlyphRuns.Length();
return mGlyphRuns.Elements();
}
// Returns the index of the GlyphRun containing the given offset.
// Returns mGlyphRuns.Length() when aOffset is mCharacterCount.
PRUint32 FindFirstGlyphRunContaining(PRUint32 aOffset);
// Copy glyph data for a range of characters from aSource to this
// textrun. If aStealData is true then we actually steal the glyph data,
// setting the data in aSource to "missing". aDest should be in the last
// glyphrun.
virtual void CopyGlyphDataFrom(gfxTextRun *aSource, PRUint32 aStart,
PRUint32 aLength, PRUint32 aDest,
PRBool aStealData);
nsExpirationState *GetExpirationState() { return &mExpirationState; }
struct LigatureData {
// textrun offsets of the start and end of the containing ligature
PRUint32 mLigatureStart;
PRUint32 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;
PRPackedBool mPartIsStartOfLigature;
PRPackedBool mPartIsEndOfLigature;
};
#ifdef DEBUG
// number of entries referencing this textrun in the gfxTextRunWordCache
PRUint32 mCachedWords;
void Dump(FILE* aOutput);
#endif
protected:
// Allocates extra space for the CompressedGlyph array and the text
// (if needed)
void *operator new(size_t aSize, PRUint32 aLength, PRUint32 aFlags);
/**
* Initializes the textrun to blank.
* @param aObjectSize the size of the object; this lets us fine
* where our CompressedGlyph array and string have been allocated
*/
gfxTextRun(const gfxTextRunFactory::Parameters *aParams, const void *aText,
PRUint32 aLength, gfxFontGroup *aFontGroup, PRUint32 aFlags,
PRUint32 aObjectSize);
private:
// **** general helpers ****
// Allocate aCount DetailedGlyphs for the given index
DetailedGlyph *AllocateDetailedGlyphs(PRUint32 aCharIndex, PRUint32 aCount);
// 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.
PRBool GetAdjustedSpacingArray(PRUint32 aStart, PRUint32 aEnd,
PropertyProvider *aProvider,
PRUint32 aSpacingStart, PRUint32 aSpacingEnd,
nsTArray<PropertyProvider::Spacing> *aSpacing);
// **** 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(PRUint32 aPartStart, PRUint32 aPartEnd,
PropertyProvider *aProvider);
gfxFloat ComputePartialLigatureWidth(PRUint32 aPartStart, PRUint32 aPartEnd,
PropertyProvider *aProvider);
void DrawPartialLigature(gfxFont *aFont, gfxContext *aCtx, PRUint32 aStart,
PRUint32 aEnd, const gfxRect *aDirtyRect, gfxPoint *aPt,
PropertyProvider *aProvider);
// Advance aStart to the start of the nearest ligature; back up aEnd
// to the nearest ligature end; may result in *aStart == *aEnd
void ShrinkToLigatureBoundaries(PRUint32 *aStart, PRUint32 *aEnd);
// result in appunits
gfxFloat GetPartialLigatureWidth(PRUint32 aStart, PRUint32 aEnd, PropertyProvider *aProvider);
void AccumulatePartialLigatureMetrics(gfxFont *aFont,
PRUint32 aStart, PRUint32 aEnd, PRBool aTight,
gfxContext *aRefContext,
PropertyProvider *aProvider,
Metrics *aMetrics);
// **** measurement helper ****
void AccumulateMetricsForRun(gfxFont *aFont, PRUint32 aStart,
PRUint32 aEnd, PRBool aTight,
gfxContext *aRefContext,
PropertyProvider *aProvider,
PRUint32 aSpacingStart, PRUint32 aSpacingEnd,
Metrics *aMetrics);
// **** drawing helper ****
void DrawGlyphs(gfxFont *aFont, gfxContext *aContext, PRBool aDrawToPath,
gfxPoint *aPt, PRUint32 aStart, PRUint32 aEnd,
PropertyProvider *aProvider,
PRUint32 aSpacingStart, PRUint32 aSpacingEnd);
// All our glyph data is in logical order, not visual.
// mCharacterGlyphs is allocated fused with this object. We need a pointer
// to it because gfxTextRun subclasses exist with extra fields, so we don't
// know where it starts without a virtual method call or an explicit pointer.
CompressedGlyph* mCharacterGlyphs;
nsAutoArrayPtr<nsAutoArrayPtr<DetailedGlyph> > mDetailedGlyphs; // only non-null if needed
// 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;
// When TEXT_IS_8BIT is set, we use mSingle, otherwise we use mDouble.
// When TEXT_IS_PERSISTENT is set, we don't own the text, otherwise we
// own the text. When we own the text, it's allocated fused with this
// object, so it need not be deleted.
// This text is not null-terminated.
union {
const PRUint8 *mSingle;
const PRUnichar *mDouble;
} mText;
void *mUserData;
gfxFontGroup *mFontGroup; // addrefed
gfxSkipChars mSkipChars;
nsExpirationState mExpirationState;
PRUint32 mAppUnitsPerDevUnit;
PRUint32 mFlags;
PRUint32 mCharacterCount;
PRUint32 mHashCode;
};
class THEBES_API gfxFontGroup : public gfxTextRunFactory {
public:
gfxFontGroup(const nsAString& aFamilies, const gfxFontStyle *aStyle);
virtual ~gfxFontGroup() {
mFonts.Clear();
}
virtual gfxFont *GetFontAt(PRInt32 i) {
return static_cast<gfxFont*>(mFonts[i]);
}
virtual PRUint32 FontListLength() const {
return mFonts.Length();
}
PRBool Equals(const gfxFontGroup& other) const {
return mFamilies.Equals(other.mFamilies) &&
mStyle.Equals(other.mStyle);
}
const gfxFontStyle *GetStyle() const { return &mStyle; }
virtual gfxFontGroup *Copy(const gfxFontStyle *aStyle) = 0;
/**
* The listed characters should not be passed in to MakeTextRun and should
* be treated as invisible and zero-width.
*/
static PRBool IsInvalidChar(PRUnichar ch) {
if (ch >= 32) {
return ch == 0x0085/*NEL*/ ||
((ch & 0xFF00) == 0x2000 /* Unicode control character */ &&
(ch == 0x200B/*ZWSP*/ || ch == 0x2028/*LSEP*/ || ch == 0x2029/*PSEP*/ ||
IS_BIDI_CONTROL_CHAR(ch)));
}
// We could just blacklist all control characters, but it seems better
// to only blacklist the ones we know cause problems for native font
// engines.
return ch == 0x0B || ch == '\t' || ch == '\r' || ch == '\n' || ch == '\f' ||
(ch >= 0x1c && ch <= 0x1f);
}
/**
* Make a textrun for an empty string. This is fast; if you call it,
* don't bother caching the result.
*/
gfxTextRun *MakeEmptyTextRun(const Parameters *aParams, PRUint32 aFlags);
/**
* Make a textrun for a single ASCII space. This is fast; if you call it,
* don't bother caching the result.
*/
gfxTextRun *MakeSpaceTextRun(const Parameters *aParams, PRUint32 aFlags);
/**
* 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 PRUnichar *aString, PRUint32 aLength,
const Parameters *aParams, PRUint32 aFlags) = 0;
/**
* 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 PRUint8 *aString, PRUint32 aLength,
const Parameters *aParams, PRUint32 aFlags) = 0;
/* helper function for splitting font families on commas and
* calling a function for each family to fill the mFonts array
*/
typedef PRBool (*FontCreationCallback) (const nsAString& aName,
const nsACString& aGenericName,
void *closure);
static PRBool ForEachFont(const nsAString& aFamilies,
const nsACString& aLangGroup,
FontCreationCallback fc,
void *closure);
PRBool ForEachFont(FontCreationCallback fc, void *closure);
const nsString& GetFamilies() { return mFamilies; }
// 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.
gfxFloat GetUnderlineOffset() {
if (mUnderlineOffset == 0)
mUnderlineOffset = GetFontAt(0)->GetMetrics().underlineOffset;
return mUnderlineOffset;
}
protected:
nsString mFamilies;
gfxFontStyle mStyle;
nsTArray< nsRefPtr<gfxFont> > mFonts;
gfxFloat mUnderlineOffset;
// 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);
/* If aResolveGeneric is true, then CSS/Gecko generic family names are
* replaced with preferred fonts.
*
* If aResolveFontName is true then fc() is called only for existing fonts
* and with actual font names. If false then fc() is called with each
* family name in aFamilies (after resolving CSS/Gecko generic family names
* if aResolveGeneric).
*/
static PRBool ForEachFontInternal(const nsAString& aFamilies,
const nsACString& aLangGroup,
PRBool aResolveGeneric,
PRBool aResolveFontName,
FontCreationCallback fc,
void *closure);
static PRBool FontResolverProc(const nsAString& aName, void *aClosure);
};
#endif
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