gecko-dev/gfx/thebes/gfxGraphiteShaper.cpp
2012-05-21 12:12:37 +01:00

431 lines
14 KiB
C++

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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/. */
#include "prtypes.h"
#include "prmem.h"
#include "nsString.h"
#include "nsBidiUtils.h"
#include "nsMathUtils.h"
#include "gfxTypes.h"
#include "gfxContext.h"
#include "gfxPlatform.h"
#include "gfxGraphiteShaper.h"
#include "gfxFontUtils.h"
#include "graphite2/Font.h"
#include "graphite2/Segment.h"
#include "harfbuzz/hb.h"
#include "cairo.h"
#include "nsUnicodeRange.h"
#include "nsCRT.h"
#define FloatToFixed(f) (65536 * (f))
#define FixedToFloat(f) ((f) * (1.0 / 65536.0))
// Right shifts of negative (signed) integers are undefined, as are overflows
// when converting unsigned to negative signed integers.
// (If speed were an issue we could make some 2's complement assumptions.)
#define FixedToIntRound(f) ((f) > 0 ? ((32768 + (f)) >> 16) \
: -((32767 - (f)) >> 16))
using namespace mozilla; // for AutoSwap_* types
/*
* Creation and destruction; on deletion, release any font tables we're holding
*/
gfxGraphiteShaper::gfxGraphiteShaper(gfxFont *aFont)
: gfxFontShaper(aFont),
mGrFace(nsnull),
mGrFont(nsnull),
mUseFontGlyphWidths(false)
{
mTables.Init();
mCallbackData.mFont = aFont;
mCallbackData.mShaper = this;
}
PLDHashOperator
ReleaseTableFunc(const PRUint32& /* aKey */,
gfxGraphiteShaper::TableRec& aData,
void* /* aUserArg */)
{
hb_blob_destroy(aData.mBlob);
return PL_DHASH_REMOVE;
}
gfxGraphiteShaper::~gfxGraphiteShaper()
{
if (mGrFont) {
gr_font_destroy(mGrFont);
}
if (mGrFace) {
gr_face_destroy(mGrFace);
}
mTables.Enumerate(ReleaseTableFunc, nsnull);
}
static const void*
GrGetTable(const void* appFaceHandle, unsigned int name, size_t *len)
{
const gfxGraphiteShaper::CallbackData *cb =
static_cast<const gfxGraphiteShaper::CallbackData*>(appFaceHandle);
return cb->mShaper->GetTable(name, len);
}
const void*
gfxGraphiteShaper::GetTable(PRUint32 aTag, size_t *aLength)
{
TableRec tableRec;
if (!mTables.Get(aTag, &tableRec)) {
hb_blob_t *blob = mFont->GetFontTable(aTag);
if (blob) {
// mFont->GetFontTable() gives us a reference to the blob.
// We will destroy (release) it in our destructor.
tableRec.mBlob = blob;
tableRec.mData = hb_blob_get_data(blob, &tableRec.mLength);
mTables.Put(aTag, tableRec);
} else {
return nsnull;
}
}
*aLength = tableRec.mLength;
return tableRec.mData;
}
static float
GrGetAdvance(const void* appFontHandle, gr_uint16 glyphid)
{
const gfxGraphiteShaper::CallbackData *cb =
static_cast<const gfxGraphiteShaper::CallbackData*>(appFontHandle);
return FixedToFloat(cb->mFont->GetGlyphWidth(cb->mContext, glyphid));
}
static inline PRUint32
MakeGraphiteLangTag(PRUint32 aTag)
{
PRUint32 grLangTag = aTag;
// replace trailing space-padding with NULs for graphite
PRUint32 mask = 0x000000FF;
while ((grLangTag & mask) == ' ') {
grLangTag &= ~mask;
mask <<= 8;
}
return grLangTag;
}
struct GrFontFeatures {
gr_face *mFace;
gr_feature_val *mFeatures;
};
static PLDHashOperator
AddFeature(const PRUint32& aTag, PRUint32& aValue, void *aUserArg)
{
GrFontFeatures *f = static_cast<GrFontFeatures*>(aUserArg);
const gr_feature_ref* fref = gr_face_find_fref(f->mFace, aTag);
if (fref) {
gr_fref_set_feature_value(fref, aValue, f->mFeatures);
}
return PL_DHASH_NEXT;
}
bool
gfxGraphiteShaper::ShapeWord(gfxContext *aContext,
gfxShapedWord *aShapedWord,
const PRUnichar *aText)
{
// some font back-ends require this in order to get proper hinted metrics
if (!mFont->SetupCairoFont(aContext)) {
return false;
}
mCallbackData.mContext = aContext;
if (!mGrFont) {
mGrFace = gr_make_face(&mCallbackData, GrGetTable, gr_face_default);
if (!mGrFace) {
return false;
}
mGrFont = mUseFontGlyphWidths ?
gr_make_font_with_advance_fn(mFont->GetAdjustedSize(),
&mCallbackData, GrGetAdvance,
mGrFace) :
gr_make_font(mFont->GetAdjustedSize(), mGrFace);
if (!mGrFont) {
gr_face_destroy(mGrFace);
mGrFace = nsnull;
return false;
}
}
gfxFontEntry *entry = mFont->GetFontEntry();
const gfxFontStyle *style = mFont->GetStyle();
PRUint32 grLang = 0;
if (style->languageOverride) {
grLang = MakeGraphiteLangTag(style->languageOverride);
} else if (entry->mLanguageOverride) {
grLang = MakeGraphiteLangTag(entry->mLanguageOverride);
} else {
nsCAutoString langString;
style->language->ToUTF8String(langString);
grLang = GetGraphiteTagForLang(langString);
}
gr_feature_val *grFeatures = gr_face_featureval_for_lang(mGrFace, grLang);
nsDataHashtable<nsUint32HashKey,PRUint32> mergedFeatures;
if (MergeFontFeatures(style->featureSettings, entry->mFeatureSettings,
aShapedWord->DisableLigatures(), mergedFeatures)) {
// enumerate result and insert into Graphite feature list
GrFontFeatures f = {mGrFace, grFeatures};
mergedFeatures.Enumerate(AddFeature, &f);
}
gr_segment *seg = gr_make_seg(mGrFont, mGrFace, 0, grFeatures,
gr_utf16, aText, aShapedWord->Length(),
aShapedWord->IsRightToLeft());
gr_featureval_destroy(grFeatures);
if (!seg) {
return false;
}
nsresult rv = SetGlyphsFromSegment(aShapedWord, seg);
gr_seg_destroy(seg);
return NS_SUCCEEDED(rv);
}
#define SMALL_GLYPH_RUN 256 // avoid heap allocation of per-glyph data arrays
// for short (typical) runs up to this length
struct Cluster {
PRUint32 baseChar;
PRUint32 baseGlyph;
PRUint32 nChars;
PRUint32 nGlyphs;
Cluster() : baseChar(0), baseGlyph(0), nChars(0), nGlyphs(0) { }
};
nsresult
gfxGraphiteShaper::SetGlyphsFromSegment(gfxShapedWord *aShapedWord,
gr_segment *aSegment)
{
PRInt32 dev2appUnits = aShapedWord->AppUnitsPerDevUnit();
bool rtl = aShapedWord->IsRightToLeft();
PRUint32 glyphCount = gr_seg_n_slots(aSegment);
// identify clusters; graphite may have reordered/expanded/ligated glyphs.
nsAutoTArray<Cluster,SMALL_GLYPH_RUN> clusters;
nsAutoTArray<PRUint16,SMALL_GLYPH_RUN> gids;
nsAutoTArray<float,SMALL_GLYPH_RUN> xLocs;
nsAutoTArray<float,SMALL_GLYPH_RUN> yLocs;
if (!clusters.SetLength(aShapedWord->Length()) ||
!gids.SetLength(glyphCount) ||
!xLocs.SetLength(glyphCount) ||
!yLocs.SetLength(glyphCount))
{
return NS_ERROR_OUT_OF_MEMORY;
}
// walk through the glyph slots and check which original character
// each is associated with
PRUint32 gIndex = 0; // glyph slot index
PRUint32 cIndex = 0; // current cluster index
for (const gr_slot *slot = gr_seg_first_slot(aSegment);
slot != nsnull;
slot = gr_slot_next_in_segment(slot), gIndex++)
{
PRUint32 before = gr_slot_before(slot);
PRUint32 after = gr_slot_after(slot);
gids[gIndex] = gr_slot_gid(slot);
xLocs[gIndex] = gr_slot_origin_X(slot);
yLocs[gIndex] = gr_slot_origin_Y(slot);
// if this glyph has a "before" character index that precedes the
// current cluster's char index, we need to merge preceding
// clusters until it gets included
while (before < clusters[cIndex].baseChar && cIndex > 0) {
clusters[cIndex-1].nChars += clusters[cIndex].nChars;
clusters[cIndex-1].nGlyphs += clusters[cIndex].nGlyphs;
--cIndex;
}
// if there's a gap between the current cluster's base character and
// this glyph's, extend the cluster to include the intervening chars
if (gr_slot_can_insert_before(slot) && clusters[cIndex].nChars &&
before >= clusters[cIndex].baseChar + clusters[cIndex].nChars)
{
NS_ASSERTION(cIndex < aShapedWord->Length() - 1, "cIndex at end of word");
Cluster& c = clusters[cIndex + 1];
c.baseChar = clusters[cIndex].baseChar + clusters[cIndex].nChars;
c.nChars = before - c.baseChar;
c.baseGlyph = gIndex;
c.nGlyphs = 0;
++cIndex;
}
// increment cluster's glyph count to include current slot
NS_ASSERTION(cIndex < aShapedWord->Length(), "cIndex beyond word length");
++clusters[cIndex].nGlyphs;
// extend cluster if necessary to reach the glyph's "after" index
if (clusters[cIndex].baseChar + clusters[cIndex].nChars < after + 1) {
clusters[cIndex].nChars = after + 1 - clusters[cIndex].baseChar;
}
}
// now put glyphs into the textrun, one cluster at a time
for (PRUint32 i = 0; i <= cIndex; ++i) {
const Cluster& c = clusters[i];
float adv; // total advance of the cluster
if (rtl) {
if (i == 0) {
adv = gr_seg_advance_X(aSegment) - xLocs[c.baseGlyph];
} else {
adv = xLocs[clusters[i-1].baseGlyph] - xLocs[c.baseGlyph];
}
} else {
if (i == cIndex) {
adv = gr_seg_advance_X(aSegment) - xLocs[c.baseGlyph];
} else {
adv = xLocs[clusters[i+1].baseGlyph] - xLocs[c.baseGlyph];
}
}
// Check for default-ignorable char that didn't get filtered, combined,
// etc by the shaping process, and skip it.
PRUint32 offs = gr_cinfo_base(gr_seg_cinfo(aSegment, c.baseChar));
NS_ASSERTION(offs >= c.baseChar && offs < aShapedWord->Length(),
"unexpected offset");
if (c.nGlyphs == 1 && c.nChars == 1 &&
aShapedWord->FilterIfIgnorable(offs))
{
continue;
}
PRUint32 appAdvance = adv * dev2appUnits;
if (c.nGlyphs == 1 &&
gfxShapedWord::CompressedGlyph::IsSimpleGlyphID(gids[c.baseGlyph]) &&
gfxShapedWord::CompressedGlyph::IsSimpleAdvance(appAdvance) &&
yLocs[c.baseGlyph] == 0)
{
gfxShapedWord::CompressedGlyph g;
aShapedWord->SetSimpleGlyph(offs,
g.SetSimpleGlyph(appAdvance,
gids[c.baseGlyph]));
} else {
// not a one-to-one mapping with simple metrics: use DetailedGlyph
nsAutoTArray<gfxShapedWord::DetailedGlyph,8> details;
float clusterLoc;
for (PRUint32 j = c.baseGlyph; j < c.baseGlyph + c.nGlyphs; ++j) {
gfxShapedWord::DetailedGlyph* d = details.AppendElement();
d->mGlyphID = gids[j];
d->mYOffset = -yLocs[j] * dev2appUnits;
if (j == c.baseGlyph) {
d->mXOffset = 0;
d->mAdvance = appAdvance;
clusterLoc = xLocs[j];
} else {
d->mXOffset = (xLocs[j] - clusterLoc - adv) * dev2appUnits;
d->mAdvance = 0;
}
}
gfxShapedWord::CompressedGlyph g;
g.SetComplex(aShapedWord->IsClusterStart(offs),
true, details.Length());
aShapedWord->SetGlyphs(offs, g, details.Elements());
}
for (PRUint32 j = c.baseChar + 1; j < c.baseChar + c.nChars; ++j) {
offs = gr_cinfo_base(gr_seg_cinfo(aSegment, j));
NS_ASSERTION(offs >= j && offs < aShapedWord->Length(),
"unexpected offset");
gfxShapedWord::CompressedGlyph g;
g.SetComplex(aShapedWord->IsClusterStart(offs), false, 0);
aShapedWord->SetGlyphs(offs, g, nsnull);
}
}
return NS_OK;
}
// for language tag validation - include list of tags from the IANA registry
#include "gfxLanguageTagList.cpp"
nsTHashtable<nsUint32HashKey> gfxGraphiteShaper::sLanguageTags;
/*static*/ PRUint32
gfxGraphiteShaper::GetGraphiteTagForLang(const nsCString& aLang)
{
int len = aLang.Length();
if (len < 2) {
return 0;
}
// convert primary language subtag to a left-packed, NUL-padded integer
// for the Graphite API
PRUint32 grLang = 0;
for (int i = 0; i < 4; ++i) {
grLang <<= 8;
if (i < len) {
PRUint8 ch = aLang[i];
if (ch == '-') {
// found end of primary language subtag, truncate here
len = i;
continue;
}
if (ch < 'a' || ch > 'z') {
// invalid character in tag, so ignore it completely
return 0;
}
grLang += ch;
}
}
// valid tags must have length = 2 or 3
if (len < 2 || len > 3) {
return 0;
}
if (!sLanguageTags.IsInitialized()) {
// store the registered IANA tags in a hash for convenient validation
sLanguageTags.Init(ArrayLength(sLanguageTagList));
for (const PRUint32 *tag = sLanguageTagList; *tag != 0; ++tag) {
sLanguageTags.PutEntry(*tag);
}
}
// only accept tags known in the IANA registry
if (sLanguageTags.GetEntry(grLang)) {
return grLang;
}
return 0;
}
/*static*/ void
gfxGraphiteShaper::Shutdown()
{
#ifdef NS_FREE_PERMANENT_DATA
if (sLanguageTags.IsInitialized()) {
sLanguageTags.Clear();
}
#endif
}