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gecko-dev/gfx/thebes/gfxHarfBuzzShaper.cpp

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/* -*- 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 "nsAlgorithm.h"
#include "nsString.h"
#include "nsBidiUtils.h"
#include "nsMathUtils.h"
#include "gfxTypes.h"
#include "gfxContext.h"
#include "gfxPlatform.h"
#include "gfxHarfBuzzShaper.h"
#include "gfxFontUtils.h"
#include "nsUnicodeProperties.h"
#include "nsUnicodeScriptCodes.h"
#include "nsUnicodeNormalizer.h"
#include "harfbuzz/hb.h"
#include "harfbuzz/hb-ot.h"
#include "cairo.h"
#include "nsCRT.h"
#include <algorithm>
#if defined(XP_WIN)
#include "gfxWindowsPlatform.h"
#endif
#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
using namespace mozilla::unicode; // for Unicode property lookup
/*
* Creation and destruction; on deletion, release any font tables we're holding
*/
gfxHarfBuzzShaper::gfxHarfBuzzShaper(gfxFont *aFont)
: gfxFontShaper(aFont),
mHBFace(nullptr),
mKernTable(nullptr),
mHmtxTable(nullptr),
mNumLongMetrics(0),
mCmapTable(nullptr),
mCmapFormat(-1),
mSubtableOffset(0),
mUVSTableOffset(0),
mUseFontGetGlyph(aFont->ProvidesGetGlyph()),
mUseFontGlyphWidths(false)
{
}
gfxHarfBuzzShaper::~gfxHarfBuzzShaper()
{
hb_blob_destroy(mCmapTable);
hb_blob_destroy(mHmtxTable);
hb_blob_destroy(mKernTable);
hb_face_destroy(mHBFace);
}
/*
* HarfBuzz callback access to font table data
*/
// callback for HarfBuzz to get a font table (in hb_blob_t form)
// from the shaper (passed as aUserData)
static hb_blob_t *
HBGetTable(hb_face_t *face, hb_tag_t aTag, void *aUserData)
{
gfxHarfBuzzShaper *shaper = static_cast<gfxHarfBuzzShaper*>(aUserData);
gfxFont *font = shaper->GetFont();
// bug 589682 - ignore the GDEF table in buggy fonts (applies to
// Italic and BoldItalic faces of Times New Roman)
if (aTag == TRUETYPE_TAG('G','D','E','F') &&
font->GetFontEntry()->IgnoreGDEF()) {
return nullptr;
}
// bug 721719 - ignore the GSUB table in buggy fonts (applies to Roboto,
// at least on some Android ICS devices; set in gfxFT2FontList.cpp)
if (aTag == TRUETYPE_TAG('G','S','U','B') &&
font->GetFontEntry()->IgnoreGSUB()) {
return nullptr;
}
return font->GetFontTable(aTag);
}
/*
* HarfBuzz font callback functions; font_data is a ptr to a
* FontCallbackData struct
*/
struct FontCallbackData {
FontCallbackData(gfxHarfBuzzShaper *aShaper, gfxContext *aContext)
: mShaper(aShaper), mContext(aContext)
{ }
gfxHarfBuzzShaper *mShaper;
gfxContext *mContext;
};
#define UNICODE_BMP_LIMIT 0x10000
hb_codepoint_t
gfxHarfBuzzShaper::GetGlyph(hb_codepoint_t unicode,
hb_codepoint_t variation_selector) const
{
hb_codepoint_t gid;
if (mUseFontGetGlyph) {
gid = mFont->GetGlyph(unicode, variation_selector);
} else {
// we only instantiate a harfbuzz shaper if there's a cmap available
NS_ASSERTION(mFont->GetFontEntry()->HasCmapTable(),
"we cannot be using this font!");
NS_ASSERTION(mCmapTable && (mCmapFormat > 0) && (mSubtableOffset > 0),
"cmap data not correctly set up, expect disaster");
const uint8_t* data =
(const uint8_t*)hb_blob_get_data(mCmapTable, nullptr);
switch (mCmapFormat) {
case 4:
gid = unicode < UNICODE_BMP_LIMIT ?
gfxFontUtils::MapCharToGlyphFormat4(data + mSubtableOffset,
unicode) : 0;
break;
case 12:
gid = gfxFontUtils::MapCharToGlyphFormat12(data + mSubtableOffset,
unicode);
break;
default:
NS_WARNING("unsupported cmap format, glyphs will be missing");
gid = 0;
break;
}
if (gid && variation_selector && mUVSTableOffset) {
hb_codepoint_t varGID =
gfxFontUtils::MapUVSToGlyphFormat14(data + mUVSTableOffset,
unicode,
variation_selector);
if (varGID) {
gid = varGID;
}
// else the variation sequence was not supported, use default
// mapping of the character code alone
}
}
if (!gid) {
// if there's no glyph for &nbsp;, just use the space glyph instead
if (unicode == 0xA0) {
gid = mFont->GetSpaceGlyph();
}
}
return gid;
}
static hb_bool_t
HBGetGlyph(hb_font_t *font, void *font_data,
hb_codepoint_t unicode, hb_codepoint_t variation_selector,
hb_codepoint_t *glyph,
void *user_data)
{
const FontCallbackData *fcd =
static_cast<const FontCallbackData*>(font_data);
*glyph = fcd->mShaper->GetGlyph(unicode, variation_selector);
return *glyph != 0;
}
struct HMetricsHeader {
AutoSwap_PRUint32 tableVersionNumber;
AutoSwap_PRInt16 ascender;
AutoSwap_PRInt16 descender;
AutoSwap_PRInt16 lineGap;
AutoSwap_PRUint16 advanceWidthMax;
AutoSwap_PRInt16 minLeftSideBearing;
AutoSwap_PRInt16 minRightSideBearing;
AutoSwap_PRInt16 xMaxExtent;
AutoSwap_PRInt16 caretSlopeRise;
AutoSwap_PRInt16 caretSlopeRun;
AutoSwap_PRInt16 caretOffset;
AutoSwap_PRInt16 reserved[4];
AutoSwap_PRInt16 metricDataFormat;
AutoSwap_PRUint16 numberOfHMetrics;
};
struct HLongMetric {
AutoSwap_PRUint16 advanceWidth;
AutoSwap_PRInt16 lsb;
};
struct HMetrics {
HLongMetric metrics[1]; // actually numberOfHMetrics
// the variable-length metrics[] array is immediately followed by:
// AutoSwap_PRUint16 leftSideBearing[];
};
hb_position_t
gfxHarfBuzzShaper::GetGlyphHAdvance(gfxContext *aContext,
hb_codepoint_t glyph) const
{
if (mUseFontGlyphWidths) {
return mFont->GetGlyphWidth(aContext, glyph);
}
// font did not implement GetHintedGlyphWidth, so get an unhinted value
// directly from the font tables
NS_ASSERTION((mNumLongMetrics > 0) && mHmtxTable != nullptr,
"font is lacking metrics, we shouldn't be here");
if (glyph >= uint32_t(mNumLongMetrics)) {
glyph = mNumLongMetrics - 1;
}
// glyph must be valid now, because we checked during initialization
// that mNumLongMetrics is > 0, and that the hmtx table is large enough
// to contain mNumLongMetrics records
const HMetrics* hmtx =
reinterpret_cast<const HMetrics*>(hb_blob_get_data(mHmtxTable, nullptr));
return FloatToFixed(mFont->FUnitsToDevUnitsFactor() *
uint16_t(hmtx->metrics[glyph].advanceWidth));
}
static hb_position_t
HBGetGlyphHAdvance(hb_font_t *font, void *font_data,
hb_codepoint_t glyph, void *user_data)
{
const FontCallbackData *fcd =
static_cast<const FontCallbackData*>(font_data);
return fcd->mShaper->GetGlyphHAdvance(fcd->mContext, glyph);
}
static hb_bool_t
HBGetContourPoint(hb_font_t *font, void *font_data,
unsigned int point_index, hb_codepoint_t glyph,
hb_position_t *x, hb_position_t *y,
void *user_data)
{
/* not yet implemented - no support for used of hinted contour points
to fine-tune anchor positions in GPOS AnchorFormat2 */
return false;
}
struct KernHeaderFmt0 {
AutoSwap_PRUint16 nPairs;
AutoSwap_PRUint16 searchRange;
AutoSwap_PRUint16 entrySelector;
AutoSwap_PRUint16 rangeShift;
};
struct KernPair {
AutoSwap_PRUint16 left;
AutoSwap_PRUint16 right;
AutoSwap_PRInt16 value;
};
// Find a kern pair in a Format 0 subtable.
// The aSubtable parameter points to the subtable itself, NOT its header,
// as the header structure differs between Windows and Mac (v0 and v1.0)
// versions of the 'kern' table.
// aSubtableLen is the length of the subtable EXCLUDING its header.
// If the pair <aFirstGlyph,aSecondGlyph> is found, the kerning value is
// added to aValue, so that multiple subtables can accumulate a total
// kerning value for a given pair.
static void
GetKernValueFmt0(const void* aSubtable,
uint32_t aSubtableLen,
uint16_t aFirstGlyph,
uint16_t aSecondGlyph,
int32_t& aValue,
bool aIsOverride = false,
bool aIsMinimum = false)
{
const KernHeaderFmt0* hdr =
reinterpret_cast<const KernHeaderFmt0*>(aSubtable);
const KernPair *lo = reinterpret_cast<const KernPair*>(hdr + 1);
const KernPair *hi = lo + uint16_t(hdr->nPairs);
const KernPair *limit = hi;
if (reinterpret_cast<const char*>(aSubtable) + aSubtableLen <
reinterpret_cast<const char*>(hi)) {
// subtable is not large enough to contain the claimed number
// of kern pairs, so just ignore it
return;
}
#define KERN_PAIR_KEY(l,r) (uint32_t((uint16_t(l) << 16) + uint16_t(r)))
uint32_t key = KERN_PAIR_KEY(aFirstGlyph, aSecondGlyph);
while (lo < hi) {
const KernPair *mid = lo + (hi - lo) / 2;
if (KERN_PAIR_KEY(mid->left, mid->right) < key) {
lo = mid + 1;
} else {
hi = mid;
}
}
if (lo < limit && KERN_PAIR_KEY(lo->left, lo->right) == key) {
if (aIsOverride) {
aValue = int16_t(lo->value);
} else if (aIsMinimum) {
aValue = std::max(aValue, int32_t(lo->value));
} else {
aValue += int16_t(lo->value);
}
}
}
// Get kerning value from Apple (version 1.0) kern table,
// subtable format 2 (simple N x M array of kerning values)
// See http://developer.apple.com/fonts/TTRefMan/RM06/Chap6kern.html
// for details of version 1.0 format 2 subtable.
struct KernHeaderVersion1Fmt2 {
KernTableSubtableHeaderVersion1 header;
AutoSwap_PRUint16 rowWidth;
AutoSwap_PRUint16 leftOffsetTable;
AutoSwap_PRUint16 rightOffsetTable;
AutoSwap_PRUint16 array;
};
struct KernClassTableHdr {
AutoSwap_PRUint16 firstGlyph;
AutoSwap_PRUint16 nGlyphs;
AutoSwap_PRUint16 offsets[1]; // actually an array of nGlyphs entries
};
static int16_t
GetKernValueVersion1Fmt2(const void* aSubtable,
uint32_t aSubtableLen,
uint16_t aFirstGlyph,
uint16_t aSecondGlyph)
{
if (aSubtableLen < sizeof(KernHeaderVersion1Fmt2)) {
return 0;
}
const char* base = reinterpret_cast<const char*>(aSubtable);
const char* subtableEnd = base + aSubtableLen;
const KernHeaderVersion1Fmt2* h =
reinterpret_cast<const KernHeaderVersion1Fmt2*>(aSubtable);
uint32_t offset = h->array;
const KernClassTableHdr* leftClassTable =
reinterpret_cast<const KernClassTableHdr*>(base +
uint16_t(h->leftOffsetTable));
if (reinterpret_cast<const char*>(leftClassTable) +
sizeof(KernClassTableHdr) > subtableEnd) {
return 0;
}
if (aFirstGlyph >= uint16_t(leftClassTable->firstGlyph)) {
aFirstGlyph -= uint16_t(leftClassTable->firstGlyph);
if (aFirstGlyph < uint16_t(leftClassTable->nGlyphs)) {
if (reinterpret_cast<const char*>(leftClassTable) +
sizeof(KernClassTableHdr) +
aFirstGlyph * sizeof(uint16_t) >= subtableEnd) {
return 0;
}
offset = uint16_t(leftClassTable->offsets[aFirstGlyph]);
}
}
const KernClassTableHdr* rightClassTable =
reinterpret_cast<const KernClassTableHdr*>(base +
uint16_t(h->rightOffsetTable));
if (reinterpret_cast<const char*>(rightClassTable) +
sizeof(KernClassTableHdr) > subtableEnd) {
return 0;
}
if (aSecondGlyph >= uint16_t(rightClassTable->firstGlyph)) {
aSecondGlyph -= uint16_t(rightClassTable->firstGlyph);
if (aSecondGlyph < uint16_t(rightClassTable->nGlyphs)) {
if (reinterpret_cast<const char*>(rightClassTable) +
sizeof(KernClassTableHdr) +
aSecondGlyph * sizeof(uint16_t) >= subtableEnd) {
return 0;
}
offset += uint16_t(rightClassTable->offsets[aSecondGlyph]);
}
}
const AutoSwap_PRInt16* pval =
reinterpret_cast<const AutoSwap_PRInt16*>(base + offset);
if (reinterpret_cast<const char*>(pval + 1) >= subtableEnd) {
return 0;
}
return *pval;
}
// Get kerning value from Apple (version 1.0) kern table,
// subtable format 3 (simple N x M array of kerning values)
// See http://developer.apple.com/fonts/TTRefMan/RM06/Chap6kern.html
// for details of version 1.0 format 3 subtable.
struct KernHeaderVersion1Fmt3 {
KernTableSubtableHeaderVersion1 header;
AutoSwap_PRUint16 glyphCount;
uint8_t kernValueCount;
uint8_t leftClassCount;
uint8_t rightClassCount;
uint8_t flags;
};
static int16_t
GetKernValueVersion1Fmt3(const void* aSubtable,
uint32_t aSubtableLen,
uint16_t aFirstGlyph,
uint16_t aSecondGlyph)
{
// check that we can safely read the header fields
if (aSubtableLen < sizeof(KernHeaderVersion1Fmt3)) {
return 0;
}
const KernHeaderVersion1Fmt3* hdr =
reinterpret_cast<const KernHeaderVersion1Fmt3*>(aSubtable);
if (hdr->flags != 0) {
return 0;
}
uint16_t glyphCount = hdr->glyphCount;
// check that table is large enough for the arrays
if (sizeof(KernHeaderVersion1Fmt3) +
hdr->kernValueCount * sizeof(int16_t) +
glyphCount + glyphCount +
hdr->leftClassCount * hdr->rightClassCount > aSubtableLen) {
return 0;
}
if (aFirstGlyph >= glyphCount || aSecondGlyph >= glyphCount) {
// glyphs are out of range for the class tables
return 0;
}
// get pointers to the four arrays within the subtable
const AutoSwap_PRInt16* kernValue =
reinterpret_cast<const AutoSwap_PRInt16*>(hdr + 1);
const uint8_t* leftClass =
reinterpret_cast<const uint8_t*>(kernValue + hdr->kernValueCount);
const uint8_t* rightClass = leftClass + glyphCount;
const uint8_t* kernIndex = rightClass + glyphCount;
uint8_t lc = leftClass[aFirstGlyph];
uint8_t rc = rightClass[aSecondGlyph];
if (lc >= hdr->leftClassCount || rc >= hdr->rightClassCount) {
return 0;
}
uint8_t ki = kernIndex[leftClass[aFirstGlyph] * hdr->rightClassCount +
rightClass[aSecondGlyph]];
if (ki >= hdr->kernValueCount) {
return 0;
}
return kernValue[ki];
}
#define KERN0_COVERAGE_HORIZONTAL 0x0001
#define KERN0_COVERAGE_MINIMUM 0x0002
#define KERN0_COVERAGE_CROSS_STREAM 0x0004
#define KERN0_COVERAGE_OVERRIDE 0x0008
#define KERN0_COVERAGE_RESERVED 0x00F0
#define KERN1_COVERAGE_VERTICAL 0x8000
#define KERN1_COVERAGE_CROSS_STREAM 0x4000
#define KERN1_COVERAGE_VARIATION 0x2000
#define KERN1_COVERAGE_RESERVED 0x1F00
hb_position_t
gfxHarfBuzzShaper::GetHKerning(uint16_t aFirstGlyph,
uint16_t aSecondGlyph) const
{
// We want to ignore any kern pairs involving <space>, because we are
// handling words in isolation, the only space characters seen here are
// the ones artificially added by the textRun code.
uint32_t spaceGlyph = mFont->GetSpaceGlyph();
if (aFirstGlyph == spaceGlyph || aSecondGlyph == spaceGlyph) {
return 0;
}
if (!mKernTable) {
mKernTable = mFont->GetFontTable(TRUETYPE_TAG('k','e','r','n'));
if (!mKernTable) {
mKernTable = hb_blob_get_empty();
}
}
uint32_t len;
const char* base = hb_blob_get_data(mKernTable, &len);
if (len < sizeof(KernTableVersion0)) {
return 0;
}
int32_t value = 0;
// First try to interpret as "version 0" kern table
// (see http://www.microsoft.com/typography/otspec/kern.htm)
const KernTableVersion0* kern0 =
reinterpret_cast<const KernTableVersion0*>(base);
if (uint16_t(kern0->version) == 0) {
uint16_t nTables = kern0->nTables;
uint32_t offs = sizeof(KernTableVersion0);
for (uint16_t i = 0; i < nTables; ++i) {
if (offs + sizeof(KernTableSubtableHeaderVersion0) > len) {
break;
}
const KernTableSubtableHeaderVersion0* st0 =
reinterpret_cast<const KernTableSubtableHeaderVersion0*>
(base + offs);
uint16_t subtableLen = uint16_t(st0->length);
if (offs + subtableLen > len) {
break;
}
offs += subtableLen;
uint16_t coverage = st0->coverage;
if (!(coverage & KERN0_COVERAGE_HORIZONTAL)) {
// we only care about horizontal kerning (for now)
continue;
}
if (coverage &
(KERN0_COVERAGE_CROSS_STREAM | KERN0_COVERAGE_RESERVED)) {
// we don't support cross-stream kerning, and
// reserved bits should be zero;
// ignore the subtable if not
continue;
}
uint8_t format = (coverage >> 8);
switch (format) {
case 0:
GetKernValueFmt0(st0 + 1, subtableLen - sizeof(*st0),
aFirstGlyph, aSecondGlyph, value,
(coverage & KERN0_COVERAGE_OVERRIDE) != 0,
(coverage & KERN0_COVERAGE_MINIMUM) != 0);
break;
default:
// TODO: implement support for other formats,
// if they're ever used in practice
#if DEBUG
{
char buf[1024];
sprintf(buf, "unknown kern subtable in %s: "
"ver 0 format %d\n",
NS_ConvertUTF16toUTF8(mFont->GetName()).get(),
format);
NS_WARNING(buf);
}
#endif
break;
}
}
} else {
// It wasn't a "version 0" table; check if it is Apple version 1.0
// (see http://developer.apple.com/fonts/TTRefMan/RM06/Chap6kern.html)
const KernTableVersion1* kern1 =
reinterpret_cast<const KernTableVersion1*>(base);
if (uint32_t(kern1->version) == 0x00010000) {
uint32_t nTables = kern1->nTables;
uint32_t offs = sizeof(KernTableVersion1);
for (uint32_t i = 0; i < nTables; ++i) {
if (offs + sizeof(KernTableSubtableHeaderVersion1) > len) {
break;
}
const KernTableSubtableHeaderVersion1* st1 =
reinterpret_cast<const KernTableSubtableHeaderVersion1*>
(base + offs);
uint32_t subtableLen = uint32_t(st1->length);
offs += subtableLen;
uint16_t coverage = st1->coverage;
if (coverage &
(KERN1_COVERAGE_VERTICAL |
KERN1_COVERAGE_CROSS_STREAM |
KERN1_COVERAGE_VARIATION |
KERN1_COVERAGE_RESERVED)) {
// we only care about horizontal kerning (for now),
// we don't support cross-stream kerning,
// we don't support variations,
// reserved bits should be zero;
// ignore the subtable if not
continue;
}
uint8_t format = (coverage & 0xff);
switch (format) {
case 0:
GetKernValueFmt0(st1 + 1, subtableLen - sizeof(*st1),
aFirstGlyph, aSecondGlyph, value);
break;
case 2:
value = GetKernValueVersion1Fmt2(st1, subtableLen,
aFirstGlyph, aSecondGlyph);
break;
case 3:
value = GetKernValueVersion1Fmt3(st1, subtableLen,
aFirstGlyph, aSecondGlyph);
break;
default:
// TODO: implement support for other formats.
// Note that format 1 cannot be supported here,
// as it requires the full glyph array to run the FSM,
// not just the current glyph pair.
#if DEBUG
{
char buf[1024];
sprintf(buf, "unknown kern subtable in %s: "
"ver 0 format %d\n",
NS_ConvertUTF16toUTF8(mFont->GetName()).get(),
format);
NS_WARNING(buf);
}
#endif
break;
}
}
}
}
if (value != 0) {
return FloatToFixed(mFont->FUnitsToDevUnitsFactor() * value);
}
return 0;
}
static hb_position_t
HBGetHKerning(hb_font_t *font, void *font_data,
hb_codepoint_t first_glyph, hb_codepoint_t second_glyph,
void *user_data)
{
const FontCallbackData *fcd =
static_cast<const FontCallbackData*>(font_data);
return fcd->mShaper->GetHKerning(first_glyph, second_glyph);
}
/*
* HarfBuzz unicode property callbacks
*/
static hb_codepoint_t
HBGetMirroring(hb_unicode_funcs_t *ufuncs, hb_codepoint_t aCh,
void *user_data)
{
return GetMirroredChar(aCh);
}
static hb_unicode_general_category_t
HBGetGeneralCategory(hb_unicode_funcs_t *ufuncs, hb_codepoint_t aCh,
void *user_data)
{
return hb_unicode_general_category_t(GetGeneralCategory(aCh));
}
static hb_script_t
HBGetScript(hb_unicode_funcs_t *ufuncs, hb_codepoint_t aCh, void *user_data)
{
return hb_script_t(GetScriptTagForCode(GetScriptCode(aCh)));
}
static hb_unicode_combining_class_t
HBGetCombiningClass(hb_unicode_funcs_t *ufuncs, hb_codepoint_t aCh,
void *user_data)
{
return hb_unicode_combining_class_t(GetCombiningClass(aCh));
}
static unsigned int
HBGetEastAsianWidth(hb_unicode_funcs_t *ufuncs, hb_codepoint_t aCh,
void *user_data)
{
return GetEastAsianWidth(aCh);
}
// Hebrew presentation forms with dagesh, for characters 0x05D0..0x05EA;
// note that some letters do not have a dagesh presForm encoded
static const PRUnichar sDageshForms[0x05EA - 0x05D0 + 1] = {
0xFB30, // ALEF
0xFB31, // BET
0xFB32, // GIMEL
0xFB33, // DALET
0xFB34, // HE
0xFB35, // VAV
0xFB36, // ZAYIN
0, // HET
0xFB38, // TET
0xFB39, // YOD
0xFB3A, // FINAL KAF
0xFB3B, // KAF
0xFB3C, // LAMED
0, // FINAL MEM
0xFB3E, // MEM
0, // FINAL NUN
0xFB40, // NUN
0xFB41, // SAMEKH
0, // AYIN
0xFB43, // FINAL PE
0xFB44, // PE
0, // FINAL TSADI
0xFB46, // TSADI
0xFB47, // QOF
0xFB48, // RESH
0xFB49, // SHIN
0xFB4A // TAV
};
static hb_bool_t
HBUnicodeCompose(hb_unicode_funcs_t *ufuncs,
hb_codepoint_t a,
hb_codepoint_t b,
hb_codepoint_t *ab,
void *user_data)
{
hb_bool_t found = nsUnicodeNormalizer::Compose(a, b, ab);
if (!found && (b & 0x1fff80) == 0x0580) {
// special-case Hebrew presentation forms that are excluded from
// standard normalization, but wanted for old fonts
switch (b) {
case 0x05B4: // HIRIQ
if (a == 0x05D9) { // YOD
*ab = 0xFB1D;
found = true;
}
break;
case 0x05B7: // patah
if (a == 0x05F2) { // YIDDISH YOD YOD
*ab = 0xFB1F;
found = true;
} else if (a == 0x05D0) { // ALEF
*ab = 0xFB2E;
found = true;
}
break;
case 0x05B8: // QAMATS
if (a == 0x05D0) { // ALEF
*ab = 0xFB2F;
found = true;
}
break;
case 0x05B9: // HOLAM
if (a == 0x05D5) { // VAV
*ab = 0xFB4B;
found = true;
}
break;
case 0x05BC: // DAGESH
if (a >= 0x05D0 && a <= 0x05EA) {
*ab = sDageshForms[a - 0x05D0];
found = (*ab != 0);
} else if (a == 0xFB2A) { // SHIN WITH SHIN DOT
*ab = 0xFB2C;
found = true;
} else if (a == 0xFB2B) { // SHIN WITH SIN DOT
*ab = 0xFB2D;
found = true;
}
break;
case 0x05BF: // RAFE
switch (a) {
case 0x05D1: // BET
*ab = 0xFB4C;
found = true;
break;
case 0x05DB: // KAF
*ab = 0xFB4D;
found = true;
break;
case 0x05E4: // PE
*ab = 0xFB4E;
found = true;
break;
}
break;
case 0x05C1: // SHIN DOT
if (a == 0x05E9) { // SHIN
*ab = 0xFB2A;
found = true;
} else if (a == 0xFB49) { // SHIN WITH DAGESH
*ab = 0xFB2C;
found = true;
}
break;
case 0x05C2: // SIN DOT
if (a == 0x05E9) { // SHIN
*ab = 0xFB2B;
found = true;
} else if (a == 0xFB49) { // SHIN WITH DAGESH
*ab = 0xFB2D;
found = true;
}
break;
}
}
return found;
}
static hb_bool_t
HBUnicodeDecompose(hb_unicode_funcs_t *ufuncs,
hb_codepoint_t ab,
hb_codepoint_t *a,
hb_codepoint_t *b,
void *user_data)
{
return nsUnicodeNormalizer::DecomposeNonRecursively(ab, a, b);
}
static PLDHashOperator
AddFeature(const uint32_t& aTag, uint32_t& aValue, void *aUserArg)
{
nsTArray<hb_feature_t>* features = static_cast<nsTArray<hb_feature_t>*> (aUserArg);
hb_feature_t feat = { 0, 0, 0, UINT_MAX };
feat.tag = aTag;
feat.value = aValue;
features->AppendElement(feat);
return PL_DHASH_NEXT;
}
/*
* gfxFontShaper override to initialize the text run using HarfBuzz
*/
static hb_font_funcs_t * sHBFontFuncs = nullptr;
static hb_unicode_funcs_t * sHBUnicodeFuncs = nullptr;
bool
gfxHarfBuzzShaper::ShapeText(gfxContext *aContext,
const PRUnichar *aText,
uint32_t aOffset,
uint32_t aLength,
int32_t aScript,
gfxShapedText *aShapedText)
{
// some font back-ends require this in order to get proper hinted metrics
if (!mFont->SetupCairoFont(aContext)) {
return false;
}
if (!mHBFace) {
mUseFontGlyphWidths = mFont->ProvidesGlyphWidths();
// set up the harfbuzz face etc the first time we use the font
if (!sHBFontFuncs) {
// static function callback pointers, initialized by the first
// harfbuzz shaper used
sHBFontFuncs = hb_font_funcs_create();
hb_font_funcs_set_glyph_func(sHBFontFuncs, HBGetGlyph,
nullptr, nullptr);
hb_font_funcs_set_glyph_h_advance_func(sHBFontFuncs,
HBGetGlyphHAdvance,
nullptr, nullptr);
hb_font_funcs_set_glyph_contour_point_func(sHBFontFuncs,
HBGetContourPoint,
nullptr, nullptr);
hb_font_funcs_set_glyph_h_kerning_func(sHBFontFuncs,
HBGetHKerning,
nullptr, nullptr);
sHBUnicodeFuncs =
hb_unicode_funcs_create(hb_unicode_funcs_get_empty());
hb_unicode_funcs_set_mirroring_func(sHBUnicodeFuncs,
HBGetMirroring,
nullptr, nullptr);
hb_unicode_funcs_set_script_func(sHBUnicodeFuncs, HBGetScript,
nullptr, nullptr);
hb_unicode_funcs_set_general_category_func(sHBUnicodeFuncs,
HBGetGeneralCategory,
nullptr, nullptr);
hb_unicode_funcs_set_combining_class_func(sHBUnicodeFuncs,
HBGetCombiningClass,
nullptr, nullptr);
hb_unicode_funcs_set_eastasian_width_func(sHBUnicodeFuncs,
HBGetEastAsianWidth,
nullptr, nullptr);
hb_unicode_funcs_set_compose_func(sHBUnicodeFuncs,
HBUnicodeCompose,
nullptr, nullptr);
hb_unicode_funcs_set_decompose_func(sHBUnicodeFuncs,
HBUnicodeDecompose,
nullptr, nullptr);
}
mHBFace = hb_face_create_for_tables(HBGetTable, this, nullptr);
if (!mUseFontGetGlyph) {
// get the cmap table and find offset to our subtable
mCmapTable = mFont->GetFontTable(TRUETYPE_TAG('c','m','a','p'));
if (!mCmapTable) {
NS_WARNING("failed to load cmap, glyphs will be missing");
return false;
}
uint32_t len;
const uint8_t* data = (const uint8_t*)hb_blob_get_data(mCmapTable, &len);
bool symbol;
mCmapFormat = gfxFontUtils::
FindPreferredSubtable(data, len,
&mSubtableOffset, &mUVSTableOffset,
&symbol);
}
if (!mUseFontGlyphWidths) {
// if font doesn't implement GetGlyphWidth, we will be reading
// the hmtx table directly;
// read mNumLongMetrics from hhea table without caching its blob,
// and preload/cache the hmtx table
hb_blob_t *hheaTable =
mFont->GetFontTable(TRUETYPE_TAG('h','h','e','a'));
if (hheaTable) {
uint32_t len;
const HMetricsHeader* hhea =
reinterpret_cast<const HMetricsHeader*>
(hb_blob_get_data(hheaTable, &len));
if (len >= sizeof(HMetricsHeader)) {
mNumLongMetrics = hhea->numberOfHMetrics;
if (mNumLongMetrics > 0 &&
int16_t(hhea->metricDataFormat) == 0) {
// no point reading hmtx if number of entries is zero!
// in that case, we won't be able to use this font
// (this method will return FALSE below if mHmtx is null)
mHmtxTable =
mFont->GetFontTable(TRUETYPE_TAG('h','m','t','x'));
if (hb_blob_get_length(mHmtxTable) <
mNumLongMetrics * sizeof(HLongMetric)) {
// hmtx table is not large enough for the claimed
// number of entries: invalid, do not use.
hb_blob_destroy(mHmtxTable);
mHmtxTable = nullptr;
}
}
}
}
hb_blob_destroy(hheaTable);
}
}
if ((!mUseFontGetGlyph && mCmapFormat <= 0) ||
(!mUseFontGlyphWidths && !mHmtxTable)) {
// unable to shape with this font
return false;
}
FontCallbackData fcd(this, aContext);
hb_font_t *font = hb_font_create(mHBFace);
hb_font_set_funcs(font, sHBFontFuncs, &fcd, nullptr);
hb_font_set_ppem(font, mFont->GetAdjustedSize(), mFont->GetAdjustedSize());
uint32_t scale = FloatToFixed(mFont->GetAdjustedSize()); // 16.16 fixed-point
hb_font_set_scale(font, scale, scale);
nsAutoTArray<hb_feature_t,20> features;
gfxFontEntry *entry = mFont->GetFontEntry();
const gfxFontStyle *style = mFont->GetStyle();
nsDataHashtable<nsUint32HashKey,uint32_t> mergedFeatures;
if (MergeFontFeatures(style->featureSettings,
mFont->GetFontEntry()->mFeatureSettings,
aShapedText->DisableLigatures(), mergedFeatures)) {
// enumerate result and insert into hb_feature array
mergedFeatures.Enumerate(AddFeature, &features);
}
bool isRightToLeft = aShapedText->IsRightToLeft();
hb_buffer_t *buffer = hb_buffer_create();
hb_buffer_set_unicode_funcs(buffer, sHBUnicodeFuncs);
hb_buffer_set_direction(buffer, isRightToLeft ? HB_DIRECTION_RTL :
HB_DIRECTION_LTR);
// For unresolved "common" or "inherited" runs, default to Latin for now.
// (Should we somehow use the language or locale to try and infer
// a better default?)
hb_script_t scriptTag = (aScript <= MOZ_SCRIPT_INHERITED) ?
HB_SCRIPT_LATIN :
hb_script_t(GetScriptTagForCode(aScript));
hb_buffer_set_script(buffer, scriptTag);
hb_language_t language;
if (style->languageOverride) {
language = hb_ot_tag_to_language(style->languageOverride);
} else if (entry->mLanguageOverride) {
language = hb_ot_tag_to_language(entry->mLanguageOverride);
} else {
nsCString langString;
style->language->ToUTF8String(langString);
language =
hb_language_from_string(langString.get(), langString.Length());
}
hb_buffer_set_language(buffer, language);
uint32_t length = aLength;
hb_buffer_add_utf16(buffer,
reinterpret_cast<const uint16_t*>(aText),
length, 0, length);
hb_shape(font, buffer, features.Elements(), features.Length());
if (isRightToLeft) {
hb_buffer_reverse(buffer);
}
nsresult rv = SetGlyphsFromRun(aContext, aShapedText, aOffset, aLength,
aText, buffer);
NS_WARN_IF_FALSE(NS_SUCCEEDED(rv), "failed to store glyphs into gfxShapedWord");
hb_buffer_destroy(buffer);
hb_font_destroy(font);
return NS_SUCCEEDED(rv);
}
/**
* Work out whether cairo will snap inter-glyph spacing to pixels.
*
* Layout does not align text to pixel boundaries, so, with font drawing
* backends that snap glyph positions to pixels, it is important that
* inter-glyph spacing within words is always an integer number of pixels.
* This ensures that the drawing backend snaps all of the word's glyphs in the
* same direction and so inter-glyph spacing remains the same.
*/
static void
GetRoundOffsetsToPixels(gfxContext *aContext,
bool *aRoundX, bool *aRoundY)
{
*aRoundX = false;
// Could do something fancy here for ScaleFactors of
// AxisAlignedTransforms, but we leave things simple.
// Not much point rounding if a matrix will mess things up anyway.
if (aContext->CurrentMatrix().HasNonTranslation()) {
*aRoundY = false;
return;
}
// All raster backends snap glyphs to pixels vertically.
// Print backends set CAIRO_HINT_METRICS_OFF.
*aRoundY = true;
cairo_t *cr = aContext->GetCairo();
cairo_scaled_font_t *scaled_font = cairo_get_scaled_font(cr);
// Sometimes hint metrics gets set for us, most notably for printing.
cairo_font_options_t *font_options = cairo_font_options_create();
cairo_scaled_font_get_font_options(scaled_font, font_options);
cairo_hint_metrics_t hint_metrics =
cairo_font_options_get_hint_metrics(font_options);
cairo_font_options_destroy(font_options);
switch (hint_metrics) {
case CAIRO_HINT_METRICS_OFF:
*aRoundY = false;
return;
case CAIRO_HINT_METRICS_DEFAULT:
// Here we mimic what cairo surface/font backends do. Printing
// surfaces have already been handled by hint_metrics. The
// fallback show_glyphs implementation composites pixel-aligned
// glyph surfaces, so we just pick surface/font combinations that
// override this.
switch (cairo_scaled_font_get_type(scaled_font)) {
#if CAIRO_HAS_DWRITE_FONT // dwrite backend is not in std cairo releases yet
case CAIRO_FONT_TYPE_DWRITE:
// show_glyphs is implemented on the font and so is used for
// all surface types; however, it may pixel-snap depending on
// the dwrite rendering mode
if (!cairo_dwrite_scaled_font_get_force_GDI_classic(scaled_font) &&
gfxWindowsPlatform::GetPlatform()->DWriteMeasuringMode() ==
DWRITE_MEASURING_MODE_NATURAL) {
return;
}
#endif
case CAIRO_FONT_TYPE_QUARTZ:
// Quartz surfaces implement show_glyphs for Quartz fonts
if (cairo_surface_get_type(cairo_get_target(cr)) ==
CAIRO_SURFACE_TYPE_QUARTZ) {
return;
}
default:
break;
}
// fall through:
case CAIRO_HINT_METRICS_ON:
break;
}
*aRoundX = true;
return;
}
#define SMALL_GLYPH_RUN 128 // some testing indicates that 90%+ of text runs
// will fit without requiring separate allocation
// for charToGlyphArray
nsresult
gfxHarfBuzzShaper::SetGlyphsFromRun(gfxContext *aContext,
gfxShapedText *aShapedText,
uint32_t aOffset,
uint32_t aLength,
const PRUnichar *aText,
hb_buffer_t *aBuffer)
{
uint32_t numGlyphs;
const hb_glyph_info_t *ginfo = hb_buffer_get_glyph_infos(aBuffer, &numGlyphs);
if (numGlyphs == 0) {
return NS_OK;
}
nsAutoTArray<gfxTextRun::DetailedGlyph,1> detailedGlyphs;
uint32_t wordLength = aLength;
static const int32_t NO_GLYPH = -1;
nsAutoTArray<int32_t,SMALL_GLYPH_RUN> charToGlyphArray;
if (!charToGlyphArray.SetLength(wordLength)) {
return NS_ERROR_OUT_OF_MEMORY;
}
int32_t *charToGlyph = charToGlyphArray.Elements();
for (uint32_t offset = 0; offset < wordLength; ++offset) {
charToGlyph[offset] = NO_GLYPH;
}
for (uint32_t i = 0; i < numGlyphs; ++i) {
uint32_t loc = ginfo[i].cluster;
if (loc < wordLength) {
charToGlyph[loc] = i;
}
}
int32_t glyphStart = 0; // looking for a clump that starts at this glyph
int32_t charStart = 0; // and this char index within the range of the run
bool roundX;
bool roundY;
GetRoundOffsetsToPixels(aContext, &roundX, &roundY);
int32_t appUnitsPerDevUnit = aShapedText->GetAppUnitsPerDevUnit();
gfxShapedText::CompressedGlyph *charGlyphs =
aShapedText->GetCharacterGlyphs() + aOffset;
// factor to convert 16.16 fixed-point pixels to app units
// (only used if not rounding)
double hb2appUnits = FixedToFloat(aShapedText->GetAppUnitsPerDevUnit());
// Residual from rounding of previous advance, for use in rounding the
// subsequent offset or advance appropriately. 16.16 fixed-point
//
// When rounding, the goal is to make the distance between glyphs and
// their base glyph equal to the integral number of pixels closest to that
// suggested by that shaper.
// i.e. posInfo[n].x_advance - posInfo[n].x_offset + posInfo[n+1].x_offset
//
// The value of the residual is the part of the desired distance that has
// not been included in integer offsets.
hb_position_t x_residual = 0;
// keep track of y-position to set glyph offsets if needed
nscoord yPos = 0;
const hb_glyph_position_t *posInfo =
hb_buffer_get_glyph_positions(aBuffer, nullptr);
while (glyphStart < int32_t(numGlyphs)) {
int32_t charEnd = ginfo[glyphStart].cluster;
int32_t glyphEnd = glyphStart;
int32_t charLimit = wordLength;
while (charEnd < charLimit) {
// This is normally executed once for each iteration of the outer loop,
// but in unusual cases where the character/glyph association is complex,
// the initial character range might correspond to a non-contiguous
// glyph range with "holes" in it. If so, we will repeat this loop to
// extend the character range until we have a contiguous glyph sequence.
charEnd += 1;
while (charEnd != charLimit && charToGlyph[charEnd] == NO_GLYPH) {
charEnd += 1;
}
// find the maximum glyph index covered by the clump so far
for (int32_t i = charStart; i < charEnd; ++i) {
if (charToGlyph[i] != NO_GLYPH) {
glyphEnd = std::max(glyphEnd, charToGlyph[i] + 1);
// update extent of glyph range
}
}
if (glyphEnd == glyphStart + 1) {
// for the common case of a single-glyph clump,
// we can skip the following checks
break;
}
if (glyphEnd == glyphStart) {
// no glyphs, try to extend the clump
continue;
}
// check whether all glyphs in the range are associated with the characters
// in our clump; if not, we have a discontinuous range, and should extend it
// unless we've reached the end of the text
bool allGlyphsAreWithinCluster = true;
for (int32_t i = glyphStart; i < glyphEnd; ++i) {
int32_t glyphCharIndex = ginfo[i].cluster;
if (glyphCharIndex < charStart || glyphCharIndex >= charEnd) {
allGlyphsAreWithinCluster = false;
break;
}
}
if (allGlyphsAreWithinCluster) {
break;
}
}
NS_ASSERTION(glyphStart < glyphEnd,
"character/glyph clump contains no glyphs!");
NS_ASSERTION(charStart != charEnd,
"character/glyph clump contains no characters!");
// Now charStart..charEnd is a ligature clump, corresponding to glyphStart..glyphEnd;
// Set baseCharIndex to the char we'll actually attach the glyphs to (1st of ligature),
// and endCharIndex to the limit (position beyond the last char),
// adjusting for the offset of the stringRange relative to the textRun.
int32_t baseCharIndex, endCharIndex;
while (charEnd < int32_t(wordLength) && charToGlyph[charEnd] == NO_GLYPH)
charEnd++;
baseCharIndex = charStart;
endCharIndex = charEnd;
// Then we check if the clump falls outside our actual string range;
// if so, just go to the next.
if (baseCharIndex >= int32_t(wordLength)) {
glyphStart = glyphEnd;
charStart = charEnd;
continue;
}
// Ensure we won't try to go beyond the valid length of the textRun's text
endCharIndex = std::min<int32_t>(endCharIndex, wordLength);
// Now we're ready to set the glyph info in the textRun
int32_t glyphsInClump = glyphEnd - glyphStart;
// Check for default-ignorable char that didn't get filtered, combined,
// etc by the shaping process, and remove from the run.
// (This may be done within harfbuzz eventually.)
if (glyphsInClump == 1 && baseCharIndex + 1 == endCharIndex &&
aShapedText->FilterIfIgnorable(aOffset + baseCharIndex,
aText[baseCharIndex])) {
glyphStart = glyphEnd;
charStart = charEnd;
continue;
}
hb_position_t x_offset = posInfo[glyphStart].x_offset;
hb_position_t x_advance = posInfo[glyphStart].x_advance;
nscoord xOffset, advance;
if (roundX) {
xOffset =
appUnitsPerDevUnit * FixedToIntRound(x_offset + x_residual);
// Desired distance from the base glyph to the next reference point.
hb_position_t width = x_advance - x_offset;
int intWidth = FixedToIntRound(width);
x_residual = width - FloatToFixed(intWidth);
advance = appUnitsPerDevUnit * intWidth + xOffset;
} else {
xOffset = floor(hb2appUnits * x_offset + 0.5);
advance = floor(hb2appUnits * x_advance + 0.5);
}
// Check if it's a simple one-to-one mapping
if (glyphsInClump == 1 &&
gfxTextRun::CompressedGlyph::IsSimpleGlyphID(ginfo[glyphStart].codepoint) &&
gfxTextRun::CompressedGlyph::IsSimpleAdvance(advance) &&
charGlyphs[baseCharIndex].IsClusterStart() &&
xOffset == 0 &&
posInfo[glyphStart].y_offset == 0 && yPos == 0)
{
charGlyphs[baseCharIndex].SetSimpleGlyph(advance,
ginfo[glyphStart].codepoint);
} else {
// collect all glyphs in a list to be assigned to the first char;
// there must be at least one in the clump, and we already measured
// its advance, hence the placement of the loop-exit test and the
// measurement of the next glyph
while (1) {
gfxTextRun::DetailedGlyph* details =
detailedGlyphs.AppendElement();
details->mGlyphID = ginfo[glyphStart].codepoint;
details->mXOffset = xOffset;
details->mAdvance = advance;
hb_position_t y_offset = posInfo[glyphStart].y_offset;
details->mYOffset = yPos -
(roundY ? appUnitsPerDevUnit * FixedToIntRound(y_offset)
: floor(hb2appUnits * y_offset + 0.5));
hb_position_t y_advance = posInfo[glyphStart].y_advance;
if (y_advance != 0) {
yPos -=
roundY ? appUnitsPerDevUnit * FixedToIntRound(y_advance)
: floor(hb2appUnits * y_advance + 0.5);
}
if (++glyphStart >= glyphEnd) {
break;
}
x_offset = posInfo[glyphStart].x_offset;
x_advance = posInfo[glyphStart].x_advance;
if (roundX) {
xOffset = appUnitsPerDevUnit *
FixedToIntRound(x_offset + x_residual);
// Desired distance to the next reference point. The
// residual is considered here, and includes the residual
// from the base glyph offset and subsequent advances, so
// that the distance from the base glyph is optimized
// rather than the distance from combining marks.
x_advance += x_residual;
int intAdvance = FixedToIntRound(x_advance);
x_residual = x_advance - FloatToFixed(intAdvance);
advance = appUnitsPerDevUnit * intAdvance;
} else {
xOffset = floor(hb2appUnits * x_offset + 0.5);
advance = floor(hb2appUnits * x_advance + 0.5);
}
}
gfxShapedText::CompressedGlyph g;
g.SetComplex(charGlyphs[baseCharIndex].IsClusterStart(),
true, detailedGlyphs.Length());
aShapedText->SetGlyphs(aOffset + baseCharIndex,
g, detailedGlyphs.Elements());
detailedGlyphs.Clear();
}
// the rest of the chars in the group are ligature continuations,
// no associated glyphs
while (++baseCharIndex != endCharIndex &&
baseCharIndex < int32_t(wordLength)) {
gfxShapedText::CompressedGlyph &g = charGlyphs[baseCharIndex];
NS_ASSERTION(!g.IsSimpleGlyph(), "overwriting a simple glyph");
g.SetComplex(g.IsClusterStart(), false, 0);
}
glyphStart = glyphEnd;
charStart = charEnd;
}
return NS_OK;
}
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