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// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/351564777): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif
#include "third_party/blink/renderer/platform/fonts/skia/skia_text_metrics.h"
#include "build/build_config.h"
#include "third_party/blink/renderer/platform/fonts/shaping/harfbuzz_face.h"
#include "third_party/blink/renderer/platform/wtf/math_extras.h"
#include "third_party/skia/include/core/SkFont.h"
#include "third_party/skia/include/core/SkPath.h"
namespace blink {
namespace {
template <class T>
T* advance_by_byte_size(T* p, unsigned byte_size) {
return reinterpret_cast<T*>(reinterpret_cast<uint8_t*>(p) + byte_size);
}
template <class T>
const T* advance_by_byte_size(const T* p, unsigned byte_size) {
return reinterpret_cast<const T*>(reinterpret_cast<const uint8_t*>(p) +
byte_size);
}
} // namespace
void SkFontGetGlyphWidthForHarfBuzz(const SkFont& font,
hb_codepoint_t codepoint,
hb_position_t* width) {
// We don't want to compute glyph extents for kUnmatchedVSGlyphId
// cases yet. Since we will do that during the second shaping pass,
// when VariationSelectorMode is set to kIgnoreVariationSelector.
if (codepoint == kUnmatchedVSGlyphId) {
return;
}
DCHECK_LE(codepoint, 0xFFFFu);
CHECK(width);
SkScalar sk_width;
uint16_t glyph = codepoint;
font.getWidths(&glyph, 1, &sk_width);
if (!font.isSubpixel())
sk_width = SkScalarRoundToInt(sk_width);
*width = SkiaScalarToHarfBuzzPosition(sk_width);
}
void SkFontGetGlyphWidthForHarfBuzz(const SkFont& font,
unsigned count,
const hb_codepoint_t* glyphs,
const unsigned glyph_stride,
hb_position_t* advances,
unsigned advance_stride) {
// Batch the call to getWidths because its function entry cost is not
// cheap. getWidths accepts multiple glyphd ID, but not from a sparse
// array that copy them to a regular array.
Vector<Glyph, 256> glyph_array(count);
for (unsigned i = 0; i < count;
i++, glyphs = advance_by_byte_size(glyphs, glyph_stride)) {
glyph_array[i] = *glyphs;
}
Vector<SkScalar, 256> sk_width_array(count);
font.getWidths(glyph_array.data(), count, sk_width_array.data());
if (!font.isSubpixel()) {
for (unsigned i = 0; i < count; i++)
sk_width_array[i] = SkScalarRoundToInt(sk_width_array[i]);
}
// Copy the results back to the sparse array.
for (unsigned i = 0; i < count;
i++, advances = advance_by_byte_size(advances, advance_stride)) {
*advances = SkiaScalarToHarfBuzzPosition(sk_width_array[i]);
}
}
// HarfBuzz callback to retrieve glyph extents, mainly used by HarfBuzz for
// fallback mark positioning, i.e. the situation when the font does not have
// mark anchors or other mark positioning rules, but instead HarfBuzz is
// supposed to heuristically place combining marks around base glyphs. HarfBuzz
// does this by measuring "ink boxes" of glyphs, and placing them according to
// Unicode mark classes. Above, below, centered or left or right, etc.
void SkFontGetGlyphExtentsForHarfBuzz(const SkFont& font,
hb_codepoint_t codepoint,
hb_glyph_extents_t* extents) {
// We don't want to compute glyph extents for kUnmatchedVSGlyphId
// cases yet. Since we will do that during the second shaping pass,
// when VariationSelectorMode is set to kIgnoreVariationSelector.
if (codepoint == kUnmatchedVSGlyphId) {
return;
}
DCHECK_LE(codepoint, 0xFFFFu);
CHECK(extents);
SkRect sk_bounds;
uint16_t glyph = codepoint;
#if BUILDFLAG(IS_APPLE)
// TODO(drott): Remove this once we have better metrics bounds
// on Mac, https://bugs.chromium.org/p/skia/issues/detail?id=5328
SkPath path;
if (font.getPath(glyph, &path)) {
sk_bounds = path.getBounds();
} else {
font.getBounds(&glyph, 1, &sk_bounds, nullptr);
}
#else
font.getBounds(&glyph, 1, &sk_bounds, nullptr);
#endif
if (!font.isSubpixel()) {
// Use roundOut() rather than round() to avoid rendering glyphs
// outside the visual overflow rect. crbug.com/452914.
sk_bounds.set(sk_bounds.roundOut());
}
// Invert y-axis because Skia is y-grows-down but we set up HarfBuzz to be
// y-grows-up.
extents->x_bearing = SkiaScalarToHarfBuzzPosition(sk_bounds.fLeft);
extents->y_bearing = SkiaScalarToHarfBuzzPosition(-sk_bounds.fTop);
extents->width = SkiaScalarToHarfBuzzPosition(sk_bounds.width());
extents->height = SkiaScalarToHarfBuzzPosition(-sk_bounds.height());
}
void SkFontGetBoundsForGlyph(const SkFont& font, Glyph glyph, SkRect* bounds) {
#if BUILDFLAG(IS_APPLE)
// TODO(drott): Remove this once we have better metrics bounds
// on Mac, https://bugs.chromium.org/p/skia/issues/detail?id=5328
SkPath path;
if (font.getPath(glyph, &path)) {
*bounds = path.getBounds();
} else {
// Fonts like Apple Color Emoji have no paths, fall back to bounds here.
font.getBounds(&glyph, 1, bounds, nullptr);
}
#else
font.getBounds(&glyph, 1, bounds, nullptr);
#endif
if (!font.isSubpixel()) {
SkIRect ir;
bounds->roundOut(&ir);
bounds->set(ir);
}
}
void SkFontGetBoundsForGlyphs(const SkFont& font,
const Vector<Glyph, 256>& glyphs,
SkRect* bounds) {
#if BUILDFLAG(IS_APPLE)
for (unsigned i = 0; i < glyphs.size(); i++) {
SkFontGetBoundsForGlyph(font, glyphs[i], &bounds[i]);
}
#else
static_assert(sizeof(Glyph) == 2, "Skia expects 2 bytes glyph id.");
font.getBounds(glyphs.data(), glyphs.size(), bounds, nullptr);
if (!font.isSubpixel()) {
for (unsigned i = 0; i < glyphs.size(); i++) {
SkIRect ir;
bounds[i].roundOut(&ir);
bounds[i].set(ir);
}
}
#endif
}
float SkFontGetWidthForGlyph(const SkFont& font, Glyph glyph) {
SkScalar sk_width;
font.getWidths(&glyph, 1, &sk_width);
if (!font.isSubpixel())
sk_width = SkScalarRoundToInt(sk_width);
return SkScalarToFloat(sk_width);
}
hb_position_t SkiaScalarToHarfBuzzPosition(SkScalar value) {
// We treat HarfBuzz hb_position_t as 16.16 fixed-point.
static const int kHbPosition1 = 1 << 16;
return ClampTo<int>(value * kHbPosition1);
}
} // namespace blink
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