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OpenTTD/src/fontcache.h
2025-12-07 11:25:08 +00:00

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10 KiB
C++

/*
* 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>.
*/
/** @file fontcache.h Functions to read fonts from files and cache them. */
#ifndef FONTCACHE_H
#define FONTCACHE_H
#include "gfx_type.h"
#include "provider_manager.h"
#include "spritecache_type.h"
/** Glyphs are characters from a font. */
typedef uint32_t GlyphID;
using FontIndex = uint8_t;
static const FontIndex INVALID_FONT_INDEX = std::numeric_limits<FontIndex>::max();
enum class FontLoadReason : uint8_t {
Default,
Configured,
LanguageFallback,
MissingFallback,
End,
};
/** Font cache for basic fonts. */
class FontCache {
protected:
using FontCaches = std::vector<std::unique_ptr<FontCache>>;
static FontCaches caches;
struct FontMetrics {
int height = 0;
int baseline = 0;
};
static std::array<FontMetrics, FS_END> metrics;
static std::array<FontIndex, FS_END> default_font_index;
const FontSize fs; ///< The size of the font.
FontIndex font_index; ///< The index of the font.
FontLoadReason load_reason; ///< Reason why the font is loaded.
int height = 0; ///< The height of the font.
int ascender = 0; ///< The ascender value of the font.
int descender = 0; ///< The descender value of the font.
FontCache(FontSize fs) : fs(fs) {}
static void Register(std::unique_ptr<FontCache> &&fc, FontLoadReason load_reason);
static void LoadDefaultFonts(FontSize fs);
static void LoadFallbackFonts(FontSize fs, FontLoadReason load_reason);
public:
virtual ~FontCache() = default;
static void InitializeFontCaches();
static void UninitializeFontCaches();
static void LoadFontCaches(FontSizes fontsizes);
static void ClearFontCaches(FontSizes fontsizes);
/** Default unscaled font heights. */
static const int DEFAULT_FONT_HEIGHT[FS_END];
/** Default unscaled font ascenders. */
static const int DEFAULT_FONT_ASCENDER[FS_END];
static int GetDefaultFontHeight(FontSize fs);
static inline int GetFontBaseline(FontSize fs)
{
return FontCache::metrics[fs].baseline;
}
static void AddFallback(FontSizes fontsizes, FontLoadReason load_reason, std::string_view name, std::span<const std::byte> os_data = {});
/**
* Add a fallback font, with OS-specific handle.
* @param fontsizes Fontsizes to add fallback to.
* @param name Name of font to add.
* @param handle OS-specific handle or data of font.
*/
template <typename T>
static void AddFallbackWithHandle(FontSizes fontsizes, FontLoadReason load_reason, std::string_view name, T &handle)
{
auto os_data = std::as_bytes(std::span(&handle, 1));
FontCache::AddFallback(fontsizes, load_reason, name, os_data);
}
/**
* Get the FontSize of the font.
* @return The FontSize.
*/
inline FontSize GetSize() const { return this->fs; }
inline FontIndex GetIndex() const { return this->font_index; }
inline FontLoadReason GetFontLoadReason() const { return this->load_reason; }
/**
* Get the height of the font.
* @return The height of the font.
*/
inline int GetHeight() const { return this->height; }
/**
* Get the ascender value of the font.
* @return The ascender value of the font.
*/
inline int GetAscender() const { return this->ascender; }
/**
* Get the descender value of the font.
* @return The descender value of the font.
*/
inline int GetDescender() const{ return this->descender; }
/**
* Get the nominal font size of the font.
* @return The nominal font size.
*/
virtual int GetFontSize() const { return this->height; }
/** Clear the font cache. */
virtual void ClearFontCache() = 0;
/**
* Get the glyph (sprite) of the given key.
* @param key The key to look up.
* @return The sprite.
*/
virtual const Sprite *GetGlyph(GlyphID key) = 0;
/**
* Get the width of the glyph with the given key.
* @param key The key to look up.
* @return The width.
*/
virtual uint GetGlyphWidth(GlyphID key) = 0;
/**
* Do we need to draw a glyph shadow?
* @return True if it has to be done, otherwise false.
*/
virtual bool GetDrawGlyphShadow() = 0;
/**
* Map a character into a glyph.
* @param key The character.
* @return The glyph ID used to draw the character.
*/
virtual GlyphID MapCharToGlyph(char32_t key) = 0;
/**
* Get the native OS font handle, if there is one.
* @return Opaque OS font handle.
*/
virtual const void *GetOSHandle()
{
return nullptr;
}
/**
* Get the name of this font.
* @return The name of the font.
*/
virtual std::string GetFontName() = 0;
virtual int GetGlyphYOffset();
/**
* Get span of all FontCaches.
* @return Span of all FontCaches.
*/
static inline std::span<const std::unique_ptr<FontCache>> Get()
{
return FontCache::caches;
}
/**
* Get the font cache of a given font size.
* @param fs The font size to look up.
* @return The font cache.
*/
static inline FontCache *Get(FontIndex font_index)
{
assert(font_index < FontCache::caches.size());
return FontCache::caches[font_index].get();
}
static inline int GetCharacterHeight(FontSize fs)
{
return FontCache::metrics[fs].height;
}
static void UpdateCharacterHeight(FontSize fs);
static inline FontIndex GetDefaultFontIndex(FontSize fs)
{
return FontCache::default_font_index[fs];
}
static inline class FontCache *GetDefaultFontCache(FontSize fs)
{
FontIndex index = FontCache::GetDefaultFontIndex(fs);
if (index != INVALID_FONT_INDEX) return FontCache::Get(index);
NOT_REACHED();
}
static inline FontIndex GetFontIndexForCharacter(FontSize fs, char32_t c)
{
for (auto it = std::rbegin(FontCache::caches); it != std::rend(FontCache::caches); ++it) {
FontCache *fc = it->get();
if (fc == nullptr) continue;
if (fc->GetSize() != fs) continue;
if (fc->MapCharToGlyph(c) == 0) continue;
return std::distance(std::begin(FontCache::caches), std::next(it).base());
}
return INVALID_FONT_INDEX;
}
/**
* Is this a built-in sprite font?
*/
virtual bool IsBuiltInFont() = 0;
};
/** Get the Sprite for a glyph */
inline const Sprite *GetGlyph(FontSize size, char32_t key)
{
FontIndex font_index = FontCache::GetFontIndexForCharacter(size, key);
FontCache *fc = font_index != INVALID_FONT_INDEX ? FontCache::Get(font_index) : FontCache::GetDefaultFontCache(size);
if (fc == nullptr) return nullptr;
return fc->GetGlyph(fc->MapCharToGlyph(key));
}
/** Get the width of a glyph */
inline uint GetGlyphWidth(FontSize size, char32_t key)
{
FontIndex font_index = FontCache::GetFontIndexForCharacter(size, key);
FontCache *fc = font_index != INVALID_FONT_INDEX ? FontCache::Get(font_index) : FontCache::GetDefaultFontCache(size);
if (fc == nullptr) return 0;
return fc->GetGlyphWidth(fc->MapCharToGlyph(key));
}
/** Settings for a single font. */
struct FontCacheSubSetting {
std::string font; ///< The name of the font, or path to the font.
uint size; ///< The (requested) size of the font.
struct FontCacheFallback {
FontLoadReason load_reason = FontLoadReason::LanguageFallback;
std::string name;
std::vector<std::byte> os_handle;
};
std::vector<FontCacheFallback> fallback_fonts;
};
/** Settings for the four different fonts. */
struct FontCacheSettings {
FontCacheSubSetting small; ///< The smallest font; mostly used for zoomed out view.
FontCacheSubSetting medium; ///< The normal font size.
FontCacheSubSetting large; ///< The largest font; mostly used for newspapers.
FontCacheSubSetting mono; ///< The mono space font used for license/readme viewers.
bool prefer_sprite; ///< Whether to prefer the built-in sprite font over resizable fonts.
bool global_aa; ///< Whether to anti alias all font sizes.
bool prefer_default; ///< Prefer OpenTTD's default font over autodetected fallback fonts.
};
extern FontCacheSettings _fcsettings;
/**
* Get the settings of a given font size.
* @param fs The font size to look up.
* @return The settings.
*/
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);
/** Different types of font that can be loaded. */
enum class FontType : uint8_t {
Sprite, ///< Bitmap sprites from GRF files.
TrueType, ///< Scalable TrueType fonts.
};
/** Factory for FontCaches. */
class FontCacheFactory : public BaseProvider<FontCacheFactory> {
public:
FontCacheFactory(std::string_view name, std::string_view description) : BaseProvider<FontCacheFactory>(name, description)
{
ProviderManager<FontCacheFactory>::Register(*this);
}
virtual ~FontCacheFactory()
{
ProviderManager<FontCacheFactory>::Unregister(*this);
}
virtual std::unique_ptr<FontCache> LoadFont(FontSize fs, FontType fonttype, bool search, const std::string &font_name, std::span<const std::byte> os_handle) const = 0;
virtual bool FindFallbackFont(const std::string &language_isocode, FontSizes fontsizes, class MissingGlyphSearcher *callback) const = 0;
};
class FontProviderManager : ProviderManager<FontCacheFactory> {
public:
static std::unique_ptr<FontCache> LoadFont(FontSize fs, FontType fonttype, bool search, const std::string &font_name, std::span<const std::byte> os_handle);
static bool FindFallbackFont(const std::string &language_isocode, FontSizes fontsizes, class MissingGlyphSearcher *callback);
};
/* Implemented in spritefontcache.cpp */
void InitializeUnicodeGlyphMap();
void SetUnicodeGlyph(FontSize size, char32_t key, SpriteID sprite);
#endif /* FONTCACHE_H */