fontcache.h

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/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <https://www.gnu.org/licenses/old-licenses/gpl-2.0>.
 */

 
#ifndef FONTCACHE_H
#define FONTCACHE_H
 
#include "gfx_type.h"
#include "provider_manager.h"
#include "spritecache_type.h"

typedef uint32_t GlyphID;
static const GlyphID SPRITE_GLYPH = 1U << 30;

class FontCache {
protected:
  static std::array<std::unique_ptr<FontCache>, FS_END> caches; 
  std::unique_ptr<FontCache> parent; 
  const FontSize fs; 
  int height = 0; 
  int ascender = 0; 
  int descender = 0; 
 
  FontCache(FontSize fs) : fs(fs) {}
  static void Register(std::unique_ptr<FontCache> &&fc);
 
public:
  virtual ~FontCache() = default;
 
  static void InitializeFontCaches();
  static void UninitializeFontCaches();
  static void LoadFontCaches(FontSizes fontsizes);
  static void ClearFontCaches(FontSizes fontsizes);

  static const int DEFAULT_FONT_HEIGHT[FS_END];
  static const int DEFAULT_FONT_ASCENDER[FS_END];
 
  static int GetDefaultFontHeight(FontSize fs);

  inline FontSize GetSize() const { return this->fs; }

  inline int GetHeight() const { return this->height; }

  inline int GetAscender() const { return this->ascender; }

  inline int GetDescender() const{ return this->descender; }

  virtual int GetFontSize() const { return this->height; }

  virtual void ClearFontCache() = 0;

  virtual const Sprite *GetGlyph(GlyphID key) = 0;

  virtual uint GetGlyphWidth(GlyphID key) = 0;

  virtual bool GetDrawGlyphShadow() = 0;

  virtual GlyphID MapCharToGlyph(char32_t key, bool fallback = true) = 0;

  virtual const void *GetOSHandle()
  {
    return nullptr;
  }

  virtual std::string GetFontName() = 0;

  static inline FontCache *Get(FontSize fs)
  {
    assert(fs < FS_END);
    return FontCache::caches[fs].get();
  }
 
  static std::string GetName(FontSize fs);

  inline bool HasParent()
  {
    return this->parent != nullptr;
  }

  virtual bool IsBuiltInFont() = 0;
};

inline const Sprite *GetGlyph(FontSize size, char32_t key)
{
  FontCache *fc = FontCache::Get(size);
  return fc->GetGlyph(fc->MapCharToGlyph(key));
}

inline uint GetGlyphWidth(FontSize size, char32_t key)
{
  FontCache *fc = FontCache::Get(size);
  return fc->GetGlyphWidth(fc->MapCharToGlyph(key));
}
 
inline bool GetDrawGlyphShadow(FontSize size)
{
  return FontCache::Get(size)->GetDrawGlyphShadow();
}

struct FontCacheSubSetting {
  std::string font; 
  uint size;        
 
  const void *os_handle = nullptr; 
};

struct FontCacheSettings {
  FontCacheSubSetting small;  
  FontCacheSubSetting medium; 
  FontCacheSubSetting large;  
  FontCacheSubSetting mono;   
  bool prefer_sprite;         
  bool global_aa;             
};
 
extern FontCacheSettings _fcsettings;

inline FontCacheSubSetting *GetFontCacheSubSetting(FontSize fs)
{
  switch (fs) {
    default: NOT_REACHED();
    case FS_SMALL:  return &_fcsettings.small;
    case FS_NORMAL: return &_fcsettings.medium;
    case FS_LARGE:  return &_fcsettings.large;
    case FS_MONO:   return &_fcsettings.mono;
  }
}
 
uint GetFontCacheFontSize(FontSize fs);
std::string GetFontCacheFontName(FontSize fs);
 
bool GetFontAAState();
void SetFont(FontSize fontsize, const std::string &font, uint size);

enum class FontType : uint8_t {
  Sprite, 
  TrueType, 
};

class FontCacheFactory : public BaseProvider<FontCacheFactory> {
public:
  FontCacheFactory(std::string_view name, std::string_view description) : BaseProvider<FontCacheFactory>(name, description)
  {
    ProviderManager<FontCacheFactory>::Register(*this);
  }

  ~FontCacheFactory() override
  {
    ProviderManager<FontCacheFactory>::Unregister(*this);
  }

  virtual std::unique_ptr<FontCache> LoadFont(FontSize fs, FontType fonttype) const = 0;

  virtual bool FindFallbackFont(struct FontCacheSettings *settings, const std::string &language_isocode, class MissingGlyphSearcher *callback) const = 0;
};
 
class FontProviderManager : ProviderManager<FontCacheFactory> {
public:
  static std::unique_ptr<FontCache> LoadFont(FontSize fs, FontType fonttype);
  static bool FindFallbackFont(FontCacheSettings *settings, const std::string &language_isocode, MissingGlyphSearcher *callback);
};
 
/* Implemented in spritefontcache.cpp */
void InitializeUnicodeGlyphMap();
void SetUnicodeGlyph(FontSize size, char32_t key, SpriteID sprite);
 
#endif /* FONTCACHE_H */