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/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkShaper.h"
#include "SkStream.h"
#include "SkTextBlob.h"
#include "SkTo.h"
#include "SkTypeface.h"
struct SkShaper::Impl {
sk_sp<SkTypeface> fTypeface;
};
SkShaper::SkShaper(sk_sp<SkTypeface> tf) : fImpl(new Impl) {
fImpl->fTypeface = tf ? std::move(tf) : SkTypeface::MakeDefault();
}
SkShaper::~SkShaper() {}
bool SkShaper::good() const { return true; }
// This example only uses public API, so we don't use SkUTF8_NextUnichar.
unsigned utf8_lead_byte_to_count(const char* ptr) {
uint8_t c = *(const uint8_t*)ptr;
SkASSERT(c <= 0xF7);
SkASSERT((c & 0xC0) != 0x80);
return (((0xE5 << 24) >> ((unsigned)c >> 4 << 1)) & 3) + 1;
}
SkPoint SkShaper::shape(SkTextBlobBuilder* builder,
const SkPaint& srcPaint,
const char* utf8text,
size_t textBytes,
bool leftToRight,
SkPoint point,
SkScalar width) const {
sk_ignore_unused_variable(leftToRight);
SkPaint paint(srcPaint);
paint.setTypeface(fImpl->fTypeface);
paint.setTextEncoding(SkPaint::kUTF8_TextEncoding);
int glyphCount = paint.countText(utf8text, textBytes);
if (glyphCount <= 0) {
return point;
}
SkRect bounds;
SkPaint::FontMetrics metrics;
paint.getFontMetrics(&metrics);
point.fY -= metrics.fAscent;
(void)paint.measureText(utf8text, textBytes, &bounds);
paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
const SkTextBlobBuilder::RunBuffer& runBuffer =
builder->allocRunTextPosH(paint, glyphCount, point.y(), textBytes, SkString(), &bounds);
memcpy(runBuffer.utf8text, utf8text, textBytes);
const char* txtPtr = utf8text;
for (int i = 0; i < glyphCount; ++i) {
// Each charater maps to exactly one glyph via SkGlyphCache::unicharToGlyph().
runBuffer.clusters[i] = SkToU32(txtPtr - utf8text);
txtPtr += utf8_lead_byte_to_count(txtPtr);
SkASSERT(txtPtr <= utf8text + textBytes);
}
paint.setTextEncoding(SkPaint::kUTF8_TextEncoding);
(void)paint.textToGlyphs(utf8text, textBytes, runBuffer.glyphs);
(void)paint.getTextWidths(utf8text, textBytes, runBuffer.pos);
SkScalar x = point.x();
for (int i = 0; i < glyphCount; ++i) {
SkScalar w = runBuffer.pos[i];
runBuffer.pos[i] = x;
x += w;
}
point.fY += metrics.fDescent + metrics.fLeading;
return point;
}
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