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onCharsToGlyphs to handle non-bmp on Mac.

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CTFontGetGlyphsForCharacters is a strange API for non-bmp code points.

R=caryclark@google.com

Review URL: https://codereview.chromium.org/43463005

git-svn-id: http://skia.googlecode.com/svn/trunk@11965 2bbb7eff-a529-9590-31e7-b0007b416f81
This commit is contained in:
bungeman@google.com 2013-10-25 17:49:08 +00:00
parent cc17673032
commit 72b8cb2320
2 changed files with 67 additions and 35 deletions
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97
src/ports/SkFontHost_mac.cpp
View File

@ -946,19 +946,16 @@ unsigned SkScalerContext_Mac::generateGlyphCount(void) {
uint16_t SkScalerContext_Mac::generateCharToGlyph(SkUnichar uni) {
CGGlyph cgGlyph[2];
UniChar theChar[2];
UniChar theChar[2]; // UniChar is a UTF-16 16-bit code unit.
// Get the glyph
size_t numUniChar = SkUTF16_FromUnichar(uni, theChar);
SkASSERT(sizeof(CGGlyph) <= sizeof(uint16_t));
// Undocumented behavior of CTFontGetGlyphsForCharacters with non-bmp code points.
// When a surragate pair is detected, the glyph index used is the index of the first
// UniChar of the pair (the lower location).
if (!CTFontGetGlyphsForCharacters(fCTFont, theChar, cgGlyph, numUniChar)) {
cgGlyph[0] = 0;
}
// Undocumented behavior of CTFontGetGlyphsForCharacters with non-bmp code points:
// When a surrogate pair is detected, the glyph index used is the index of the high surrogate.
// It is documented that if a mapping is unavailable, the glyph will be set to 0.
CTFontGetGlyphsForCharacters(fCTFont, theChar, cgGlyph, numUniChar);
return cgGlyph[0];
}
@ -1920,53 +1917,89 @@ void SkTypeface_Mac::onGetFontDescriptor(SkFontDescriptor* desc,
}
int SkTypeface_Mac::onCharsToGlyphs(const void* chars, Encoding encoding,
uint16_t glyphs[], int glyphCount) const {
// UniChar is utf16
uint16_t glyphs[], int glyphCount) const
{
// Undocumented behavior of CTFontGetGlyphsForCharacters with non-bmp code points:
// When a surrogate pair is detected, the glyph index used is the index of the high surrogate.
// It is documented that if a mapping is unavailable, the glyph will be set to 0.
SkAutoSTMalloc<1024, UniChar> charStorage;
const UniChar* src;
const UniChar* src; // UniChar is a UTF-16 16-bit code unit.
int srcCount;
switch (encoding) {
case kUTF8_Encoding: {
const char* u8 = (const char*)chars;
const UniChar* u16 = src = charStorage.reset(2 * glyphCount);
const char* utf8 = reinterpret_cast<const char*>(chars);
UniChar* utf16 = charStorage.reset(2 * glyphCount);
src = utf16;
for (int i = 0; i < glyphCount; ++i) {
SkUnichar uni = SkUTF8_NextUnichar(&u8);
int n = SkUTF16_FromUnichar(uni, (uint16_t*)u16);
u16 += n;
SkUnichar uni = SkUTF8_NextUnichar(&utf8);
utf16 += SkUTF16_FromUnichar(uni, utf16);
}
srcCount = utf16 - src;
break;
}
case kUTF16_Encoding:
src = (const UniChar*)chars;
break;
case kUTF32_Encoding: {
const SkUnichar* u32 = (const SkUnichar*)chars;
const UniChar* u16 = src = charStorage.reset(2 * glyphCount);
case kUTF16_Encoding: {
src = reinterpret_cast<const UniChar*>(chars);
int extra = 0;
for (int i = 0; i < glyphCount; ++i) {
int n = SkUTF16_FromUnichar(u32[i], (uint16_t*)u16);
u16 += n;
if (SkUTF16_IsHighSurrogate(src[i + extra])) {
++extra;
}
}
srcCount = glyphCount + extra;
break;
}
case kUTF32_Encoding: {
const SkUnichar* utf32 = reinterpret_cast<const SkUnichar*>(chars);
UniChar* utf16 = charStorage.reset(2 * glyphCount);
src = utf16;
for (int i = 0; i < glyphCount; ++i) {
utf16 += SkUTF16_FromUnichar(utf32[i], utf16);
}
srcCount = utf16 - src;
break;
}
}
// Our caller may not want glyphs for output, but we need to give that
// storage to CT, so we can walk it looking for the first non-zero.
// If glyphs is NULL, CT still needs glyph storage for finding the first failure.
// Also, if there are any non-bmp code points, the provided 'glyphs' storage will be inadequate.
SkAutoSTMalloc<1024, uint16_t> glyphStorage;
uint16_t* macGlyphs = glyphs;
if (NULL == macGlyphs) {
macGlyphs = glyphStorage.reset(glyphCount);
if (NULL == macGlyphs || srcCount > glyphCount) {
macGlyphs = glyphStorage.reset(srcCount);
}
if (CTFontGetGlyphsForCharacters(fFontRef, src, macGlyphs, glyphCount)) {
bool allEncoded = CTFontGetGlyphsForCharacters(fFontRef, src, macGlyphs, srcCount);
// If there were any non-bmp, then copy and compact.
// If 'glyphs' is NULL, then compact glyphStorage in-place.
// If all are bmp and 'glyphs' is non-NULL, 'glyphs' already contains the compact glyphs.
// If some are non-bmp and 'glyphs' is non-NULL, copy and compact into 'glyphs'.
uint16_t* compactedGlyphs = glyphs;
if (NULL == compactedGlyphs) {
compactedGlyphs = macGlyphs;
}
if (srcCount > glyphCount) {
int extra = 0;
for (int i = 0; i < glyphCount; ++i) {
if (SkUTF16_IsHighSurrogate(src[i + extra])) {
++extra;
}
compactedGlyphs[i] = macGlyphs[i + extra];
}
}
if (allEncoded) {
return glyphCount;
}
// If we got false, then we need to manually look for first failure
// If we got false, then we need to manually look for first failure.
for (int i = 0; i < glyphCount; ++i) {
if (0 == macGlyphs[i]) {
if (0 == compactedGlyphs[i]) {
return i;
}
}
// odd to get here, as we expected CT to have returned true up front.
// Odd to get here, as we expected CT to have returned true up front.
return glyphCount;
}

5
tests/FontHostTest.cpp
View File

@ -72,7 +72,7 @@ static void test_countGlyphs(skiatest::Reporter* reporter, SkTypeface* face) {
SkDebugf("--- typeface returned 0 glyphs [%X]\n", face->uniqueID());
}
}
#if 0
// The following three are all the same code points in various encodings.
static uint8_t utf8Chars[] = { 0x61, 0xE4, 0xB8, 0xAD, 0xD0, 0xAF, 0xD7, 0x99, 0xD7, 0x95, 0xF0, 0x9D, 0x84, 0x9E, 0x61 };
static uint16_t utf16Chars[] = { 0x0061, 0x4E2D, 0x042F, 0x05D9, 0x05D5, 0xD834, 0xDD1E, 0x0061 };
@ -115,7 +115,6 @@ static void test_charsToGlyphs(skiatest::Reporter* reporter, SkTypeface* face) {
}
}
}
#endif
static void test_fontstream(skiatest::Reporter* reporter,
SkStream* stream, int ttcIndex) {
@ -230,7 +229,7 @@ static void test_tables(skiatest::Reporter* reporter) {
test_tables(reporter, face);
test_unitsPerEm(reporter, face);
test_countGlyphs(reporter, face);
//test_charsToGlyphs(reporter, face);
test_charsToGlyphs(reporter, face);
}
}
}