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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 <hb-ot.h>
#include "SkShaper.h"
#include "SkStream.h"
#include "SkTextBlob.h"
#include "SkTypeface.h"
static const int FONT_SIZE_SCALE = 512;
namespace {
struct HBFBlobDel {
void operator()(hb_blob_t* b) { hb_blob_destroy(b); }
};
std::unique_ptr<hb_blob_t, HBFBlobDel> stream_to_blob(std::unique_ptr<SkStreamAsset> asset) {
size_t size = asset->getLength();
std::unique_ptr<hb_blob_t, HBFBlobDel> blob;
if (const void* base = asset->getMemoryBase()) {
blob.reset(hb_blob_create((char*)base, SkToUInt(size),
HB_MEMORY_MODE_READONLY, asset.release(),
[](void* p) { delete (SkStreamAsset*)p; }));
} else {
// SkDebugf("Extra SkStreamAsset copy\n");
SkAutoMalloc autoMalloc(size);
asset->read(autoMalloc.get(), size);
void* ptr = autoMalloc.get();
blob.reset(hb_blob_create((char*)autoMalloc.release(), SkToUInt(size),
HB_MEMORY_MODE_READONLY, ptr, sk_free));
}
SkASSERT(blob);
hb_blob_make_immutable(blob.get());
return blob;
}
} // namespace
struct SkShaper::Impl {
struct HBFontDel {
void operator()(hb_font_t* f) { hb_font_destroy(f); }
};
std::unique_ptr<hb_font_t, HBFontDel> fHarfBuzzFont;
struct HBBufDel {
void operator()(hb_buffer_t* b) { hb_buffer_destroy(b); }
};
std::unique_ptr<hb_buffer_t, HBBufDel> fBuffer;
sk_sp<SkTypeface> fTypeface;
};
SkShaper::SkShaper(sk_sp<SkTypeface> tf) : fImpl(new Impl) {
fImpl->fTypeface = tf ? std::move(tf) : SkTypeface::MakeDefault();
int index;
std::unique_ptr<hb_blob_t, HBFBlobDel> blob(
stream_to_blob(std::unique_ptr<SkStreamAsset>(
fImpl->fTypeface->openStream(&index))));
struct HBFaceDel {
void operator()(hb_face_t* f) { hb_face_destroy(f); }
};
std::unique_ptr<hb_face_t, HBFaceDel> face(
hb_face_create(blob.get(), (unsigned)index));
SkASSERT(face);
if (!face) {
return;
}
hb_face_set_index(face.get(), (unsigned)index);
hb_face_set_upem(face.get(), fImpl->fTypeface->getUnitsPerEm());
fImpl->fHarfBuzzFont.reset(hb_font_create(face.get()));
SkASSERT(fImpl->fHarfBuzzFont);
hb_font_set_scale(fImpl->fHarfBuzzFont.get(), FONT_SIZE_SCALE, FONT_SIZE_SCALE);
hb_ot_font_set_funcs(fImpl->fHarfBuzzFont.get());
fImpl->fBuffer.reset(hb_buffer_create());
}
SkShaper::~SkShaper() {}
bool SkShaper::good() const { return fImpl->fHarfBuzzFont != nullptr; }
SkScalar SkShaper::shape(SkTextBlobBuilder* builder,
const SkPaint& srcPaint,
const char* utf8text,
size_t textBytes,
SkPoint point) const {
SkPaint paint(srcPaint);
paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
paint.setTypeface(fImpl->fTypeface);
SkASSERT(builder);
hb_buffer_t* buffer = fImpl->fBuffer.get();
hb_buffer_add_utf8(buffer, utf8text, -1, 0, -1);
hb_buffer_guess_segment_properties(buffer);
hb_shape(fImpl->fHarfBuzzFont.get(), buffer, nullptr, 0);
unsigned len = hb_buffer_get_length(buffer);
if (len == 0) {
hb_buffer_clear_contents(buffer);
return 0;
}
hb_glyph_info_t* info = hb_buffer_get_glyph_infos(buffer, NULL);
hb_glyph_position_t* pos =
hb_buffer_get_glyph_positions(buffer, NULL);
auto runBuffer = builder->allocRunTextPos(
paint, SkToInt(len), SkToInt(textBytes), SkString());
memcpy(runBuffer.utf8text, utf8text, textBytes);
double x = point.x();
double y = point.y();
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;
}
hb_buffer_clear_contents(buffer);
return (SkScalar)x;
}
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