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Add some font fallback to SkShaper.

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Change-Id: I92d58071dc3a540e21bbe55267963504ff9da75b
Reviewed-on: https://skia-review.googlesource.com/42600
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
This commit is contained in:
Ben Wagner 2017-09-05 14:46:19 -04:00 committed by Skia Commit-Bot
parent acbdb5d990
commit 67e3a30f24
1 changed files with 106 additions and 64 deletions
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170
tools/shape/SkShaper_harfbuzz.cpp
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@ -10,6 +10,7 @@
#include <unicode/ubidi.h>
#include <unicode/unistr.h>
#include "SkFontMgr.h"
#include "SkShaper.h"
#include "SkStream.h"
#include "SkTemplates.h"
@ -100,6 +101,7 @@ SkScalar SkShaper::shape(SkTextBlobBuilder* builder,
size_t textBytes,
bool leftToRight,
SkPoint point) const {
sk_sp<SkFontMgr> fontMgr = SkFontMgr::RefDefault();
SkASSERT(builder);
UBiDiLevel bidiLevel = leftToRight ? UBIDI_DEFAULT_LTR : UBIDI_DEFAULT_RTL;
//hb_script_t script = ...
@ -146,76 +148,116 @@ SkScalar SkShaper::shape(SkTextBlobBuilder* builder,
SkPaint paint(srcPaint);
paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
paint.setTypeface(fImpl->fTypeface);
hb_font_t* hbfont = fImpl->fHarfBuzzFont.get();
HBFont fallbackHBFont;
sk_sp<SkTypeface> fallback;
while (utf16End < utf16.getBuffer() + start + length) {
hb_buffer_t* buffer = fImpl->fBuffer.get();
SkAutoTCallVProc<hb_buffer_t, hb_buffer_clear_contents> autoClearBuffer(buffer);
hb_buffer_t* buffer = fImpl->fBuffer.get();
SkAutoTCallVProc<hb_buffer_t, hb_buffer_clear_contents> autoClearBuffer(buffer);
// The difficulty here is the cluster mapping.
// If the hb_buffer is created with utf16, clusters will be pointing to the utf16 indexes,
// but the SkTextBlob can only take utf8 and utf8 cluster indexes.
// So populate the hb_buffer directly with utf32 and utf8 cluster indexes.
// Since this steps through the visual runs in order, it is expected that each run will
// start just after the previous one ended.
const UChar* utf16Start = utf16.getBuffer() + start;
const char* utf8Start;
if (utf16End == utf16Start) {
utf16Start = utf16End;
utf8Start = utf8End;
} else {
SkDEBUGFAIL("Did not expect to ever get here.");
utf16Start = utf16.getBuffer();
utf8Start = utf8text;
while (utf16Start < utf16.getBuffer() + start) {
SkUTF16_NextUnichar(&utf16Start);
SkUTF8_NextUnichar(&utf8Start);
// The difficulty here is the cluster mapping.
// If the hb_buffer is created with utf16, clusters will point to utf16 indexes,
// but the SkTextBlob can only take utf8 and utf8 cluster indexes.
// So populate the hb_buffer directly with utf32 and utf8 cluster indexes.
// Since this steps through the visual runs in order, it is expected that each run will
// start just after the previous one ended.
const UChar* utf16Start = utf16.getBuffer() + start;
const char* utf8Start;
if (utf16End == utf16Start) {
utf16Start = utf16End;
utf8Start = utf8End;
} else {
SkDEBUGFAIL("Did not expect to ever get here.");
utf16Start = utf16.getBuffer();
utf8Start = utf8text;
while (utf16Start < utf16.getBuffer() + start) {
SkUTF16_NextUnichar(&utf16Start);
SkUTF8_NextUnichar(&utf8Start);
}
}
}
const char* utf8Current = utf8Start;
const UChar* utf16Current = utf16Start;
utf16End = utf16Current + length;
while (utf16Current < utf16End) {
hb_codepoint_t u;
u = SkUTF16_NextUnichar(&utf16Current);
hb_buffer_add(buffer, u, utf8Current - utf8Start);
SkUTF8_NextUnichar(&utf8Current);
}
hb_buffer_set_content_type(buffer, HB_BUFFER_CONTENT_TYPE_UNICODE);
utf8End = utf8Current;
size_t utf8runLength = utf8End - utf8Start;
if (!SkTFitsIn<int>(utf8runLength)) {
SkDebugf("Shaping error: utf8 too long");
return (SkScalar)x;
}
hb_buffer_guess_segment_properties(buffer);
//hb_buffer_set_script(buffer, script);
hb_buffer_set_direction(buffer, direction ? HB_DIRECTION_RTL : HB_DIRECTION_LTR);
hb_shape(fImpl->fHarfBuzzFont.get(), buffer, nullptr, 0);
unsigned len = hb_buffer_get_length(buffer);
if (len == 0) {
continue;
}
const char* utf8Current = utf8Start;
const UChar* utf16Current = utf16Start;
utf16End = utf16Current + length;
while (utf16Current < utf16End) {
const UChar* utf16Prev = utf16Current;
hb_codepoint_t u = SkUTF16_NextUnichar(&utf16Current);
bool doPartialRun = false;
hb_glyph_info_t* info = hb_buffer_get_glyph_infos(buffer, nullptr);
hb_glyph_position_t* pos = hb_buffer_get_glyph_positions(buffer, nullptr);
// If using a fallback and the initial typeface has this character, stop fallback.
if (fallbackHBFont &&
fImpl->fTypeface->charsToGlyphs(&u, SkTypeface::kUTF32_Encoding, nullptr, 1))
{
fallback.reset();
doPartialRun = true;
if (!SkTFitsIn<int>(len)) {
SkDebugf("Shaping error: too many glyphs");
return (SkScalar)x;
}
auto runBuffer = builder->allocRunTextPos(paint, len, utf8runLength, SkString());
memcpy(runBuffer.utf8text, utf8Start, utf8runLength);
// If the current typeface does not have this character, try a fallback.
} else if (!paint.getTypeface()->charsToGlyphs(&u, SkTypeface::kUTF32_Encoding,
nullptr, 1))
{
fallback.reset(fontMgr->matchFamilyStyleCharacter(nullptr,
fImpl->fTypeface->fontStyle(),
nullptr, 0,
u));
if (fallback) {
doPartialRun = true;
}
}
if (doPartialRun) {
utf16End = utf16Prev;
int32_t oldStart = start;
start = utf16End - utf16.getBuffer();
length -= start - oldStart;
break;
}
hb_buffer_add(buffer, u, utf8Current - utf8Start);
SkUTF8_NextUnichar(&utf8Current);
}
hb_buffer_set_content_type(buffer, HB_BUFFER_CONTENT_TYPE_UNICODE);
utf8End = utf8Current;
size_t utf8runLength = utf8End - utf8Start;
if (!SkTFitsIn<int>(utf8runLength)) {
SkDebugf("Shaping error: utf8 too long");
return (SkScalar)x;
}
hb_buffer_guess_segment_properties(buffer);
//hb_buffer_set_script(buffer, script);
hb_buffer_set_direction(buffer, direction ? HB_DIRECTION_RTL : HB_DIRECTION_LTR);
hb_shape(hbfont, buffer, nullptr, 0);
unsigned len = hb_buffer_get_length(buffer);
if (len > 0) {
hb_glyph_info_t* info = hb_buffer_get_glyph_infos(buffer, nullptr);
hb_glyph_position_t* pos = hb_buffer_get_glyph_positions(buffer, nullptr);
double textSizeY = paint.getTextSize() / (double)FONT_SIZE_SCALE;
double textSizeX = textSizeY * paint.getTextScaleX();
if (!SkTFitsIn<int>(len)) {
SkDebugf("Shaping error: too many glyphs");
return (SkScalar)x;
}
auto runBuffer = builder->allocRunTextPos(paint, len, utf8runLength, SkString());
memcpy(runBuffer.utf8text, utf8Start, utf8runLength);
for (unsigned i = 0; i < len; i++) {
runBuffer.glyphs[i] = info[i].codepoint;
runBuffer.clusters[i] = info[i].cluster;
reinterpret_cast<SkPoint*>(runBuffer.pos)[i] =
SkPoint::Make(SkDoubleToScalar(x + pos[i].x_offset * textSizeX),
SkDoubleToScalar(y - pos[i].y_offset * textSizeY));
x += pos[i].x_advance * textSizeX;
y += pos[i].y_advance * textSizeY;
double textSizeY = paint.getTextSize() / (double)FONT_SIZE_SCALE;
double textSizeX = textSizeY * paint.getTextScaleX();
for (unsigned i = 0; i < len; i++) {
runBuffer.glyphs[i] = info[i].codepoint;
runBuffer.clusters[i] = info[i].cluster;
reinterpret_cast<SkPoint*>(runBuffer.pos)[i] =
SkPoint::Make(SkDoubleToScalar(x + pos[i].x_offset * textSizeX),
SkDoubleToScalar(y - pos[i].y_offset * textSizeY));
x += pos[i].x_advance * textSizeX;
y += pos[i].y_advance * textSizeY;
}
}
if (fallback) {
paint.setTypeface(std::move(fallback));
fallbackHBFont = create_hb_font(paint.getTypeface());
hbfont = fallbackHBFont.get();
} else {
paint.setTypeface(fImpl->fTypeface);
fallbackHBFont = nullptr;
hbfont = fImpl->fHarfBuzzFont.get();
}
}
}
return (SkScalar)x;