MyGUI_ResourceTrueTypeFont.h

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/*
 * This source file is part of MyGUI. For the latest info, see http://mygui.info/
 * Distributed under the MIT License
 * (See accompanying file COPYING.MIT or copy at http://opensource.org/licenses/MIT)
 */
 
#ifndef MYGUI_RESOURCE_TRUE_TYPE_FONT_H_
#define MYGUI_RESOURCE_TRUE_TYPE_FONT_H_
 
#include "MyGUI_Prerequest.h"
#include "MyGUI_ITexture.h"
#include "MyGUI_IFont.h"
 
#ifdef MYGUI_USE_FREETYPE
    #include <ft2build.h>
    #include FT_FREETYPE_H
 
    #ifdef MYGUI_MSDF_FONTS
namespace msdfgen
{
    class FontHandle;
    class Shape;
}
    #endif
 
#endif // MYGUI_USE_FREETYPE
 
#include <unordered_map>
 
namespace MyGUI
{
 
    class MYGUI_EXPORT ResourceTrueTypeFont : public IFont, public ITextureInvalidateListener
    {
        MYGUI_RTTI_DERIVED(ResourceTrueTypeFont)
 
    public:
        ~ResourceTrueTypeFont() override;
 
        void deserialization(xml::ElementPtr _node, Version _version) override;
 
        // Returns the glyph info for the specified code point, or the glyph info for a substitute glyph if the code point does not
        // exist in this font. Returns nullptr if there is a problem with the font.
        const GlyphInfo* getGlyphInfo(Char _id) const override;
 
        ITexture* getTextureFont() const override;
 
        // получившаяся высота при генерации в пикселях
        int getDefaultHeight() const override;
 
        // update texture after render device lost event
        void textureInvalidate(ITexture* _texture) override;
 
        // Returns a collection of code-point ranges that are supported by this font. Each range is specified as [first, second];
        // for example, a range containing a single code point will have the same value for both first and second.
        std::vector<std::pair<Char, Char>> getCodePointRanges() const;
 
        // Returns the code point that is used as a substitute for code points that don't exist in the font. The default substitute
        // code point is FontCodeType::NotDefined, but it can be customized in the font definition file.
        Char getSubstituteCodePoint() const;
 
        // создаение ресурса по текущим значениям
        void initialise();
 
        void setSource(std::string_view _value);
        void setShader(std::string_view _value);
        void setSize(float _value);
        void setResolution(unsigned int _value);
        void setHinting(std::string_view _value);
        void setAntialias(bool _value);
        void setTabWidth(float _value);
        void setOffsetHeight(int _value);
        void setSubstituteCode(int _value);
        void setDistance(int _value);
        void setMsdfMode(bool _value);
        void setMsdfRange(int _value);
 
        void addCodePointRange(Char _first, Char _second);
        void removeCodePointRange(Char _first, Char _second);
 
#ifdef MYGUI_USE_FREETYPE
    private:
        enum Hinting
        {
            HintingUseNative,
            HintingForceAuto,
            HintingDisableAuto,
            HintingDisableAll
        };
 
        void addCodePoint(Char _codePoint);
 
        // The following variables are set directly from values specified by the user.
        std::string mSource; // Source (filename) of the font.
        std::string mShader; // Optional shader, applied to the font.
        float mSize{0}; // Size of the font, in points (there are 72 points per inch).
        unsigned int mResolution{96}; // Resolution of the font, in pixels per inch.
        Hinting mHinting{HintingUseNative}; // What type of hinting to use when rendering the font.
        bool mAntialias{
            false}; // Whether or not to anti-alias the font by copying its alpha channel to its luminance channel.
        float mSpaceWidth{0.0f}; // The width of a "Space" character, in pixels. If zero, the default width is used.
        int mGlyphSpacing{-1}; // How far apart the glyphs are placed from each other in the font texture, in pixels.
        float mTabWidth{0.0f}; // The width of the "Tab" special character, in pixels.
        int mOffsetHeight{
            0}; // How far up to nudge text rendered in this font, in pixels. May be negative to nudge text down.
        Char mSubstituteCodePoint{static_cast<Char>(
            FontCodeType::
                NotDefined)}; // The code point to use as a substitute for code points that don't exist in the font.
        bool mMsdfMode{
            false}; // Signed distance field texture, designed to be used with shader (see https://github.com/Chlumsky/msdfgen)
        int mMsdfRange{2}; // Gragient area range in pixels for msdf mode (higher range is required for thick outlines)
 
        // The following variables are calculated automatically.
        int mDefaultHeight{0}; // The nominal height of the font in pixels.
        GlyphInfo* mSubstituteGlyphInfo{
            nullptr}; // The glyph info to use as a substitute for code points that don't exist in the font.
        MyGUI::ITexture* mTexture{nullptr}; // The texture that contains all of the rendered glyphs in the font.
 
        // The following constants used to be mutable, but they no longer need to be. Do not modify their values!
        static const int
            mDefaultGlyphSpacing; // How far apart the glyphs are placed from each other in the font texture, in pixels.
        static const float mDefaultTabWidth; // Default "Tab" width, used only when tab width is no specified.
        static const float
            mSelectedWidth; // The width of the "Selected" and "SelectedBack" special characters, in pixels.
        static const float mCursorWidth; // The width of the "Cursor" special character, in pixels.
 
    private:
        // A map of code points to glyph indices.
        using CharMap = std::map<Char, FT_UInt>;
 
        // A map of glyph indices to glyph info objects.
        using GlyphMap = std::unordered_map<Char, GlyphInfo>;
 
        // A map of glyph heights to the set of paired glyph indices and glyph info objects that are of that height.
        using GlyphHeightMap = std::map<int, std::map<FT_UInt, GlyphInfo*>>;
 
        template<bool LAMode, bool Antialias>
        void initialiseFreeType();
 
        // Loads the font face as specified by mSource, mSize, and mResolution. Automatically adjusts code-point ranges according
        // to the capabilities of the font face.
        // Returns a handle to the FreeType face object for the face, or nullptr if the face could not be loaded.
        // Keeps the font file loaded in memory and stores its location in _fontBuffer. The caller is responsible for freeing this
        // buffer when it is done using the face by calling delete[] on the buffer after calling FT_Done_Face() on the face itself.
        FT_Face loadFace(const FT_Library& _ftLibrary, uint8*& _fontBuffer);
 
        // Wraps the current texture coordinates _texX and _texY to the beginning of the next line if the specified glyph width
        // doesn't fit at the end of the current line. Automatically takes the glyph spacing into account.
        void autoWrapGlyphPos(int _glyphWidth, int _texWidth, int _lineHeight, int& _texX, int& _texY) const;
 
        // Creates a GlyphInfo object using the specified information.
        GlyphInfo createFaceGlyphInfo(Char _codePoint, int _fontAscent, FT_GlyphSlot _glyph) const;
 
        // Creates a glyph with the specified glyph index and assigns it to the specified code point.
        // Automatically updates _glyphHeightMap, mCharMap, and mGlyphMap with data from the new glyph..
        int createGlyph(FT_UInt _glyphIndex, const GlyphInfo& _glyphInfo, GlyphHeightMap& _glyphHeightMap);
 
        // Creates a glyph with the specified index from the specified font face and assigns it to the specified code point.
        // Automatically updates _glyphHeightMap with data from the newly created glyph.
        int createFaceGlyph(
            FT_UInt _glyphIndex,
            Char _codePoint,
            int _fontAscent,
            const FT_Face& _ftFace,
            FT_Int32 _ftLoadFlags,
            GlyphHeightMap& _glyphHeightMap);
 
        // Renders all of the glyphs in _glyphHeightMap into the specified texture buffer using data from the specified font face.
        template<bool LAMode, bool Antialias>
        void renderGlyphs(
            const GlyphHeightMap& _glyphHeightMap,
            const FT_Library& _ftLibrary,
            const FT_Face& _ftFace,
            FT_Int32 _ftLoadFlags,
            uint8* _texBuffer,
            int _texWidth,
            int _texHeight);
 
        // Renders the glyph described by the specified glyph info according to the specified parameters.
        // Supports two types of rendering, depending on the value of UseBuffer: Texture block transfer and rectangular color fill.
        // The _luminance0 value is used for even-numbered columns (from zero), while _luminance1 is used for odd-numbered ones.
        template<bool LAMode, bool UseBuffer, bool Antialias>
        void renderGlyph(
            GlyphInfo& _info,
            uint8 _luminance0,
            uint8 _luminance1,
            uint8 _alpha,
            int _lineHeight,
            uint8* _texBuffer,
            int _texWidth,
            int _texHeight,
            int& _texX,
            int& _texY,
            uint8* _glyphBuffer = nullptr);
 
        CharMap mCharMap; // A map of code points to glyph indices.
        GlyphMap mGlyphMap; // A map of code points to glyph info objects.
 
    #ifdef MYGUI_MSDF_FONTS
        GlyphInfo createMsdfFaceGlyphInfo(
            Char _codePoint,
            const msdfgen::Shape& _shape,
            double _advance,
            int _fontAscent);
        int createMsdfGlyph(const GlyphInfo& _glyphInfo, GlyphHeightMap& _glyphHeightMap);
        int createMsdfFaceGlyph(
            Char _codePoint,
            int _fontAscent,
            msdfgen::FontHandle* _fontHandle,
            GlyphHeightMap& _glyphHeightMap);
 
        void renderMsdfGlyphs(
            const GlyphHeightMap& _glyphHeightMap,
            msdfgen::FontHandle* _fontHandle,
            uint8* _texBuffer,
            int _texWidth,
            int _texHeight);
    #endif
 
#endif // MYGUI_USE_FREETYPE
    };
 
} // namespace MyGUI
 
#endif // MYGUI_RESOURCE_TRUE_TYPE_FONT_H_