BackendFontSDLttf.hpp

//
// TGUI - Texus' Graphical User Interface
// Copyright (C) 2012-2025 Bruno Van de Velde (vdv_b@tgui.eu)
//
// This software is provided 'as-is', without any express or implied warranty.
// In no event will the authors be held liable for any damages arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it freely,
// subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented;
//    you must not claim that you wrote the original software.
//    If you use this software in a product, an acknowledgment
//    in the product documentation would be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such,
//    and must not be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source distribution.
//
 
#ifndef TGUI_BACKEND_FONT_SDL_TTF_HPP
#define TGUI_BACKEND_FONT_SDL_TTF_HPP
 
#include <TGUI/extlibs/IncludeSDL.hpp>
#if SDL_MAJOR_VERSION >= 3
    #include <SDL3_ttf/SDL_ttf.h>
#else
    #include <SDL_ttf.h>
 
    // To keep code compatible with both SDL2_ttf and SDL3_ttf, renamed SDL2_ttf functions are mapped on their SDL3_ttf equivalent
    #define TTF_GetFontAscent TTF_FontAscent
    #define TTF_GetFontDescent TTF_FontDescent
    #define TTF_GetFontHeight TTF_FontHeight
    #define TTF_GetFontLineSkip TTF_FontLineSkip
#endif
 
#include <TGUI/Backend/Font/BackendFont.hpp>
 
#include <unordered_map>

 
namespace tgui
{
    class TGUI_API BackendFontSDLttf : public BackendFont
    {
    public:

        ~BackendFontSDLttf() override;

        bool loadFromMemory(std::unique_ptr<std::uint8_t[]> data, std::size_t sizeInBytes) override;
        using BackendFont::loadFromMemory;

        TGUI_NODISCARD bool hasGlyph(char32_t codePoint) const override;

        TGUI_NODISCARD FontGlyph getGlyph(char32_t codePoint, unsigned int characterSize, bool bold, float outlineThickness = 0) override;

        TGUI_NODISCARD float getKerning(char32_t first, char32_t second, unsigned int characterSize, bool bold) override;

        TGUI_NODISCARD float getLineSpacing(unsigned int characterSize) override;

        TGUI_NODISCARD float getFontHeight(unsigned int characterSize) override;

        TGUI_NODISCARD float getAscent(unsigned int characterSize) override;

        TGUI_NODISCARD float getDescent(unsigned int characterSize) override;

        TGUI_NODISCARD float getUnderlinePosition(unsigned int characterSize) override;

        TGUI_NODISCARD float getUnderlineThickness(unsigned int characterSize) override;

        TGUI_NODISCARD std::shared_ptr<BackendTexture> getTexture(unsigned int characterSize, unsigned int& textureVersion) override;

        TGUI_NODISCARD Vector2u getTextureSize(unsigned int characterSize) override;

        void setSmooth(bool smooth) override;

        void setFontScale(float scale) override;

        TGUI_NODISCARD TTF_Font* getInternalFont(unsigned int characterSize);

    private:

        // Finds the location and thickness of the underline, for the getUnderlinePosition and getUnderlineThickness functions
        std::pair<int, int> getUnderlineInfo(unsigned int characterSize);

        // Reserves space in the texture to place the glyph
        UIntRect findAvailableGlyphRect(unsigned int width, unsigned int height);

    private:
 
        struct Row
        {
            Row(unsigned int rowTop, unsigned int rowHeight) : width(0), top(rowTop), height(rowHeight) {}
 
            unsigned int width;  
            unsigned int top;    
            unsigned int height; 
        };
 
        std::unique_ptr<std::uint8_t[]> m_fileContents;
        std::size_t m_fileSize = 0;
 
        // TTF_Font needs a character size, so we store one font per character size
        std::unordered_map<unsigned int, TTF_Font*> m_fonts;
        std::unordered_map<unsigned int, bool> m_lastBoldFlag;
        std::unordered_map<unsigned int, int> m_lastOutlineThickness;
 
        std::unordered_map<unsigned int, std::pair<int, int>> m_cachedUnderlineInfo; // character size -> (underline vertical offset, underline thickness)
 
        std::unordered_map<std::uint64_t, FontGlyph> m_glyphs;
        unsigned int     m_nextRow = 3; 
        std::vector<Row> m_rows;
 
        std::unique_ptr<std::uint8_t[]> m_pixels;
        std::shared_ptr<BackendTexture> m_texture;
        unsigned int m_textureSize = 0;
        unsigned int m_textureVersion = 0;
    };
}

 
#endif // TGUI_BACKEND_FONT_SDL_TTF_HPP