Font.h

/*
 * Gamedev Framework (gf)
 * Copyright (C) 2016-2021 Julien Bernard
 *
 * 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.
 *
 * Part of this file comes from SFML, with the same license:
 * Copyright (C) 2007-2015 Laurent Gomila (laurent@sfml-dev.org)
 */
#ifndef GF_FONT_H
#define GF_FONT_H

#include <cstdint>
#include <map>

#include "GraphicsApi.h"
#include "Path.h"
#include "Texture.h"

namespace gf {
#ifndef DOXYGEN_SHOULD_SKIP_THIS
inline namespace v1 {
#endif

  class InputStream;

  struct GF_GRAPHICS_API Glyph {
    RectF bounds;         
    RectF textureRect;    
    float advance = 0.0f; 
  };

  class GF_GRAPHICS_API Font {
  public:
    Font();

    Font(const Path& filename);

    Font(InputStream& stream);

    Font(Span<const uint8_t> content);

    ~Font();

    Font(const Font&) = delete;

    Font& operator=(const Font&) = delete;

    Font(Font&& other) noexcept;

    Font& operator=(Font&& other) noexcept;


    const Glyph& getGlyph(char32_t codepoint, unsigned characterSize, float outlineThickness = 0.0f);

    float getKerning(char32_t left, char32_t right, unsigned characterSize);

    float getLineSpacing(unsigned characterSize);

    const AlphaTexture *getTexture(unsigned characterSize);

    void generateTexture(unsigned characterSize);

  private:
    struct Packing {
      int top = 0;
      int bottom = 0;
      int right = 0;
    };

    struct GlyphCache {
      AlphaTexture texture;
      std::map<uint64_t, Glyph> glyphs;
      Packing packing;
    };

  private:
    GlyphCache createCache();
    Glyph createGlyph(char32_t codepoint, unsigned characterSize, float outlineThickness, GlyphCache& cache);

    bool setCurrentCharacterSize(unsigned characterSize);

  private:
    void *m_library;
    void *m_stroker;
    void *m_face;
    unsigned m_currentCharacterSize;
    std::map<unsigned, GlyphCache> m_cache;
  };

#ifndef DOXYGEN_SHOULD_SKIP_THIS
}
#endif
}

#endif // GF_FONT_H