| // Copyright 2013 The Flutter Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #pragma once |
| |
| #include <functional> |
| #include <memory> |
| #include <optional> |
| #include <unordered_map> |
| |
| #include "flutter/fml/macros.h" |
| #include "impeller/core/texture.h" |
| #include "impeller/geometry/rect.h" |
| #include "impeller/renderer/pipeline.h" |
| #include "impeller/typographer/font_glyph_pair.h" |
| #include "impeller/typographer/rectangle_packer.h" |
| |
| class SkBitmap; |
| |
| namespace impeller { |
| |
| //------------------------------------------------------------------------------ |
| /// @brief A texture containing the bitmap representation of glyphs in |
| /// different fonts along with the ability to query the location of |
| /// specific font glyphs within the texture. |
| /// |
| class GlyphAtlas { |
| public: |
| //---------------------------------------------------------------------------- |
| /// @brief Describes how the glyphs are represented in the texture. |
| enum class Type { |
| //-------------------------------------------------------------------------- |
| /// The glyphs are reprsented at their requested size using only an 8-bit |
| /// alpha channel. |
| /// |
| kAlphaBitmap, |
| |
| //-------------------------------------------------------------------------- |
| /// The glyphs are reprsented at their requested size using N32 premul |
| /// colors. |
| /// |
| kColorBitmap, |
| }; |
| |
| //---------------------------------------------------------------------------- |
| /// @brief Create an empty glyph atlas. |
| /// |
| /// @param[in] type How the glyphs are represented in the texture. |
| /// |
| explicit GlyphAtlas(Type type); |
| |
| ~GlyphAtlas(); |
| |
| bool IsValid() const; |
| |
| //---------------------------------------------------------------------------- |
| /// @brief Describes how the glyphs are represented in the texture. |
| /// |
| Type GetType() const; |
| |
| //---------------------------------------------------------------------------- |
| /// @brief Set the texture for the glyph atlas. |
| /// |
| /// @param[in] texture The texture |
| /// |
| void SetTexture(std::shared_ptr<Texture> texture); |
| |
| //---------------------------------------------------------------------------- |
| /// @brief Get the texture for the glyph atlas. |
| /// |
| /// @return The texture. |
| /// |
| const std::shared_ptr<Texture>& GetTexture() const; |
| |
| //---------------------------------------------------------------------------- |
| /// @brief Record the location of a specific font-glyph pair within the |
| /// atlas. |
| /// |
| /// @param[in] pair The font-glyph pair |
| /// @param[in] rect The rectangle |
| /// |
| void AddTypefaceGlyphPosition(const FontGlyphPair& pair, Rect rect); |
| |
| //---------------------------------------------------------------------------- |
| /// @brief Get the number of unique font-glyph pairs in this atlas. |
| /// |
| /// @return The glyph count. |
| /// |
| size_t GetGlyphCount() const; |
| |
| //---------------------------------------------------------------------------- |
| /// @brief Iterate of all the glyphs along with their locations in the |
| /// atlas. |
| /// |
| /// @param[in] iterator The iterator. Return `false` from the iterator to |
| /// stop iterating. |
| /// |
| /// @return The number of glyphs iterated over. |
| /// |
| size_t IterateGlyphs( |
| const std::function<bool(const FontGlyphPair& pair, const Rect& rect)>& |
| iterator) const; |
| |
| //---------------------------------------------------------------------------- |
| /// @brief Find the location of a specific font-glyph pair in the atlas. |
| /// |
| /// @param[in] pair The font-glyph pair |
| /// |
| /// @return The location of the font-glyph pair in the atlas. |
| /// `std::nullopt` of the pair in not in the atlas. |
| /// |
| std::optional<Rect> FindFontGlyphBounds(const FontGlyphPair& pair) const; |
| |
| private: |
| const Type type_; |
| std::shared_ptr<Texture> texture_; |
| |
| std::unordered_map<FontGlyphPair, |
| Rect, |
| FontGlyphPair::Hash, |
| FontGlyphPair::Equal> |
| positions_; |
| |
| FML_DISALLOW_COPY_AND_ASSIGN(GlyphAtlas); |
| }; |
| |
| //------------------------------------------------------------------------------ |
| /// @brief A container for caching a glyph atlas across frames. |
| /// |
| class GlyphAtlasContext { |
| public: |
| GlyphAtlasContext(); |
| |
| ~GlyphAtlasContext(); |
| |
| //---------------------------------------------------------------------------- |
| /// @brief Retrieve the current glyph atlas. |
| std::shared_ptr<GlyphAtlas> GetGlyphAtlas() const; |
| |
| //---------------------------------------------------------------------------- |
| /// @brief Retrieve the size of the current glyph atlas. |
| const ISize& GetAtlasSize() const; |
| |
| //---------------------------------------------------------------------------- |
| /// @brief Retrieve the previous (if any) SkBitmap instance. |
| std::shared_ptr<SkBitmap> GetBitmap() const; |
| |
| //---------------------------------------------------------------------------- |
| /// @brief Retrieve the previous (if any) rect packer. |
| std::shared_ptr<RectanglePacker> GetRectPacker() const; |
| |
| //---------------------------------------------------------------------------- |
| /// @brief Update the context with a newly constructed glyph atlas. |
| void UpdateGlyphAtlas(std::shared_ptr<GlyphAtlas> atlas, ISize size); |
| |
| void UpdateBitmap(std::shared_ptr<SkBitmap> bitmap); |
| |
| void UpdateRectPacker(std::shared_ptr<RectanglePacker> rect_packer); |
| |
| private: |
| std::shared_ptr<GlyphAtlas> atlas_; |
| ISize atlas_size_; |
| std::shared_ptr<SkBitmap> bitmap_; |
| std::shared_ptr<RectanglePacker> rect_packer_; |
| |
| FML_DISALLOW_COPY_AND_ASSIGN(GlyphAtlasContext); |
| }; |
| |
| } // namespace impeller |