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// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_PAINT_PREVIEW_COMMON_GLYPH_USAGE_H_
#define COMPONENTS_PAINT_PREVIEW_COMMON_GLYPH_USAGE_H_
#include <stdint.h>
#include <vector>
#include "base/containers/flat_set.h"
#include "base/functional/callback_forward.h"
namespace paint_preview {
// Base class for tracking glyph usage.
class GlyphUsage {
public:
GlyphUsage();
// Range of glyph ids.
// Note: at present |first| must be 1 as we don't support offset subset codes.
GlyphUsage(uint16_t first, uint16_t last);
virtual ~GlyphUsage();
virtual void Set(uint16_t glyph_id) = 0;
virtual bool IsSet(uint16_t glyph_id) const = 0;
// Executes |callback| with the glyph id of each glyph that is set.
virtual void ForEach(
const base::RepeatingCallback<void(uint16_t)>& callback) const = 0;
bool ShouldSubset() const { return first_ < last_; }
uint16_t First() const { return first_; }
uint16_t Last() const { return last_; }
GlyphUsage& operator=(GlyphUsage&& other) noexcept;
GlyphUsage(GlyphUsage&& other) noexcept;
private:
uint16_t first_;
uint16_t last_;
GlyphUsage(const GlyphUsage&) = delete;
GlyphUsage& operator=(const GlyphUsage&) = delete;
};
// An implementation of GlyphUsage that works well for densely set glyphs.
// Usecases:
// - Primary language
// - Pre-subsetted fonts
class DenseGlyphUsage : public GlyphUsage {
public:
DenseGlyphUsage();
DenseGlyphUsage(uint16_t num_glyphs);
~DenseGlyphUsage() override;
void Set(uint16_t glyph_id) override;
bool IsSet(uint16_t glyph_id) const override;
void ForEach(
const base::RepeatingCallback<void(uint16_t)>& callback) const override;
DenseGlyphUsage& operator=(DenseGlyphUsage&& other) noexcept;
DenseGlyphUsage(DenseGlyphUsage&& other) noexcept;
private:
std::vector<bool> bitset_;
DenseGlyphUsage(const DenseGlyphUsage&) = delete;
DenseGlyphUsage& operator=(const DenseGlyphUsage&) = delete;
};
// An implementation of GlyphUsage that works well for sparsely set glyphs.
// Usecases:
// - Non-subsetted CJK fonts
// - Emoji
// - Large glyph counts fonts with low glyph usage
// - Non-primary language
class SparseGlyphUsage : public GlyphUsage {
public:
SparseGlyphUsage();
SparseGlyphUsage(uint16_t num_glyphs);
~SparseGlyphUsage() override;
void Set(uint16_t glyph_id) override;
bool IsSet(uint16_t glyph_id) const override;
void ForEach(
const base::RepeatingCallback<void(uint16_t)>& callback) const override;
SparseGlyphUsage& operator=(SparseGlyphUsage&& other) noexcept;
SparseGlyphUsage(SparseGlyphUsage&& other) noexcept;
private:
base::flat_set<uint16_t> glyph_ids_;
SparseGlyphUsage(const SparseGlyphUsage&) = delete;
SparseGlyphUsage& operator=(const SparseGlyphUsage&) = delete;
};
} // namespace paint_preview
#endif // COMPONENTS_PAINT_PREVIEW_COMMON_GLYPH_USAGE_H_
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