font_manager.h

/*
 * Copyright 2013 Jeremie Roy. All rights reserved.
 * License: https://github.com/bkaradzic/bgfx/blob/master/LICENSE
 */
 
#ifndef VCL_BGFX_TEXT_FONT_FONT_MANAGER_H
#define VCL_BGFX_TEXT_FONT_FONT_MANAGER_H
 
#include <bx/handlealloc.h>
#include <bx/string.h>
#include <bgfx/bgfx.h>
 
namespace bgfx {
 
class Atlas;
 
#define MAX_OPENED_FILES 64
#define MAX_OPENED_FONT  64
 
#define FONT_TYPE_ALPHA             UINT32_C(0x00000100) // L8
// #define FONT_TYPE_LCD               UINT32_C(0x00000200) // BGRA8
// #define FONT_TYPE_RGBA              UINT32_C(0x00000300) // BGRA8
#define FONT_TYPE_DISTANCE          UINT32_C(0x00000400) // L8
#define FONT_TYPE_DISTANCE_SUBPIXEL UINT32_C(0x00000500) // L8
#define FONT_TYPE_DISTANCE_OUTLINE  UINT32_C(0x00000600) // L8
#define FONT_TYPE_DISTANCE_OUTLINE_IMAGE  UINT32_C(0x00001600) // L8 + BGRA8
#define FONT_TYPE_DISTANCE_DROP_SHADOW  UINT32_C(0x00002700) // L8
#define FONT_TYPE_DISTANCE_DROP_SHADOW_IMAGE  UINT32_C(0x00003800) // L8 + BGRA8
#define FONT_TYPE_DISTANCE_OUTLINE_DROP_SHADOW_IMAGE  UINT32_C(0x00003900) // L8 + BGRA8
#define FONT_TYPE_MASK_DISTANCE_IMAGE UINT32_C(0x00001000)
#define FONT_TYPE_MASK_DISTANCE_DROP_SHADOW UINT32_C(0x00002000)
 
struct FontInfo
{
    uint16_t pixelSize;
    int16_t fontType;
 
    float ascender;
    float descender;
    float lineGap;
    float maxAdvanceWidth;
    float underlineThickness;
    float underlinePosition;
 
    float scale;
};
 
// Glyph metrics:
// --------------
//
//                       xmin                     xmax
//                        |                         |
//                        |<-------- width -------->|
//                        |                         |
//              |         +-------------------------+----------------- ymax
//              |         |    ggggggggg   ggggg    |     ^        ^
//              |         |   g:::::::::ggg::::g    |     |        |
//              |         |  g:::::::::::::::::g    |     |        |
//              |         | g::::::ggggg::::::gg    |     |        |
//              |         | g:::::g     g:::::g     |     |        |
//    offset_x -|-------->| g:::::g     g:::::g     |  offset_y    |
//              |         | g:::::g     g:::::g     |     |        |
//              |         | g::::::g    g:::::g     |     |        |
//              |         | g:::::::ggggg:::::g     |     |        |
//              |         |  g::::::::::::::::g     |     |      height
//              |         |   gg::::::::::::::g     |     |        |
//  baseline ---*---------|---- gggggggg::::::g-----*--------      |
//            / |         |             g:::::g     |              |
//     origin   |         | gggggg      g:::::g     |              |
//              |         | g:::::gg   gg:::::g     |              |
//              |         |  g::::::ggg:::::::g     |              |
//              |         |   gg:::::::::::::g      |              |
//              |         |     ggg::::::ggg        |              |
//              |         |         gggggg          |              v
//              |         +-------------------------+----------------- ymin
//              |                                   |
//              |------------- advance_x ---------->|
 
typedef int32_t CodePoint;
 
struct GlyphInfo
{
    int32_t glyphIndex;
 
    float width;
 
    float height;
 
    float offset_x;
 
    float offset_y;
 
    float advance_x;
 
    float advance_y;
 
    float bitmapScale;
 
    uint16_t regionIndex;
};
 
BGFX_HANDLE(TrueTypeHandle)
BGFX_HANDLE(FontHandle)
 
class FontManager
{
public:
    FontManager(Atlas* _atlas);
 
    FontManager(uint16_t _textureSideWidth = 512);
 
    ~FontManager();
 
    const Atlas* getAtlas() const
    {
        return m_atlas;
    }
 
    TrueTypeHandle createTtf(const uint8_t* _buffer, uint32_t _size);
 
    void destroyTtf(TrueTypeHandle _handle);
 
    FontHandle createFontByPixelSize(TrueTypeHandle _handle, uint32_t _typefaceIndex, uint32_t _pixelSize, uint32_t _fontType = FONT_TYPE_ALPHA,
        uint16_t _glyphWidthPadding = 6, uint16_t glyphHeightPadding = 6);
 
    FontHandle createScaledFontToPixelSize(FontHandle _baseFontHandle, uint32_t _pixelSize);
 
    void destroyFont(FontHandle _handle);
 
    bool preloadGlyph(FontHandle _handle, const wchar_t* _string);
 
    bool preloadGlyph(FontHandle _handle, CodePoint _character);
 
    bool addGlyphBitmap(FontHandle _handle, CodePoint _character, uint16_t _width, uint16_t height, uint16_t _pitch, float extraScale, const uint8_t* _bitmapBuffer, float glyphOffsetX, float glyphOffsetY);
 
    const FontInfo& getFontInfo(FontHandle _handle) const;
 
    const GlyphInfo* getGlyphInfo(FontHandle _handle, CodePoint _codePoint);
 
    float getKerning(FontHandle _handle, CodePoint _prevCodePoint, CodePoint _codePoint);
 
    const GlyphInfo& getBlackGlyph() const
    {
        return m_blackGlyph;
    }
 
private:
    struct CachedFont;
    struct CachedFile
    {
        uint8_t* buffer;
        uint32_t bufferSize;
    };
 
    void init();
    bool addBitmap(GlyphInfo& _glyphInfo, const uint8_t* _data);
 
    bool m_ownAtlas;
    Atlas* m_atlas;
 
    bx::HandleAllocT<MAX_OPENED_FONT> m_fontHandles;
    CachedFont* m_cachedFonts;
 
    bx::HandleAllocT<MAX_OPENED_FILES> m_filesHandles;
    CachedFile* m_cachedFiles;
 
    GlyphInfo m_blackGlyph;
 
    //temporary buffer to raster glyph
    uint8_t* m_buffer;
};
 
} // namespace bgfx
 
#endif // VCL_BGFX_TEXT_FONT_FONT_MANAGER_H