bgfx/examples/common/font/font_manager.h
2013-05-15 15:01:46 +02:00

206 lines
7.2 KiB
C++

/* Copyright 2013 Jeremie Roy. All rights reserved.
* License: http://www.opensource.org/licenses/BSD-2-Clause
*/
#ifndef __FONT_MANAGER_H__
#define __FONT_MANAGER_H__
#include <bgfx.h>
#include <bx/handlealloc.h>
class Atlas;
enum FontType
{
FONT_TYPE_ALPHA = 0x00000100 , // L8
//FONT_TYPE_LCD = 0x00000200, // BGRA8
//FONT_TYPE_RGBA = 0x00000300, // BGRA8
FONT_TYPE_DISTANCE = 0x00000400, // L8
FONT_TYPE_DISTANCE_SUBPIXEL = 0x00000500 // L8
};
struct FontInfo
{
//the font height in pixel
uint16_t pixelSize;
/// Rendering type used for the font
int16_t fontType;
/// The pixel extents above the baseline in pixels (typically positive)
float ascender;
/// The extents below the baseline in pixels (typically negative)
float descender;
/// The spacing in pixels between one row's descent and the next row's ascent
float lineGap;
/// The thickness of the under/hover/striketrough line in pixels
float underline_thickness;
/// The position of the underline relatively to the baseline
float underline_position;
//scale to apply to glyph data
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 ---------->|
/// Unicode value of a character
typedef int32_t CodePoint_t;
/// A structure that describe a glyph.
struct GlyphInfo
{
/// Index for faster retrieval
int32_t glyphIndex;
/// Glyph's width in pixels.
float width;
/// Glyph's height in pixels.
float height;
/// Glyph's left offset in pixels
float offset_x;
/// Glyph's top offset in pixels
/// Remember that this is the distance from the baseline to the top-most
/// glyph scan line, upwards y coordinates being positive.
float offset_y;
/// For horizontal text layouts, this is the unscaled horizontal distance in pixels
/// used to increment the pen position when the glyph is drawn as part of a string of text.
float advance_x;
/// For vertical text layouts, this is the unscaled vertical distance in pixels
/// used to increment the pen position when the glyph is drawn as part of a string of text.
float advance_y;
/// region index in the atlas storing textures
uint16_t regionIndex;
///32 bits alignment
int16_t padding;
};
BGFX_HANDLE(TrueTypeHandle);
BGFX_HANDLE(FontHandle);
class FontManager
{
public:
/// create the font manager using an external cube atlas (doesn't take ownership of the atlas)
FontManager(Atlas* _atlas);
/// create the font manager and create the texture cube as BGRA8 with linear filtering
FontManager(uint32_t _textureSideWidth = 512);
~FontManager();
/// retrieve the atlas used by the font manager (e.g. to add stuff to it)
Atlas* getAtlas() { return m_atlas; }
/// load a TrueType font from a file path
/// @return invalid handle if the loading fail
TrueTypeHandle loadTrueTypeFromFile(const char* _fontPath);
/// load a TrueType font from a given buffer.
/// the buffer is copied and thus can be freed or reused after this call
/// @return invalid handle if the loading fail
TrueTypeHandle loadTrueTypeFromMemory(const uint8_t* _buffer, uint32_t _size);
/// unload a TrueType font (free font memory) but keep loaded glyphs
void unloadTrueType(TrueTypeHandle _handle);
/// return a font whose height is a fixed pixel size
FontHandle createFontByPixelSize(TrueTypeHandle _handle, uint32_t _typefaceIndex, uint32_t _pixelSize, FontType _fontType = FONT_TYPE_ALPHA);
/// return a scaled child font whose height is a fixed pixel size
FontHandle createScaledFontToPixelSize(FontHandle _baseFontHandle, uint32_t _pixelSize);
/// load a baked font (the set of glyph is fixed)
/// @return INVALID_HANDLE if the loading fail
FontHandle loadBakedFontFromFile(const char* _imagePath, const char* _descriptorPath);
/// load a baked font (the set of glyph is fixed)
/// @return INVALID_HANDLE if the loading fail
FontHandle loadBakedFontFromMemory(const uint8_t* _imageBuffer, uint32_t _imageSize, const uint8_t* _descriptorBuffer, uint32_t _descriptorSize);
/// destroy a font (truetype or baked)
void destroyFont(FontHandle _handle);
/// Preload a set of glyphs from a TrueType file
/// @return true if every glyph could be preloaded, false otherwise
/// if the Font is a baked font, this only do validation on the characters
bool preloadGlyph(FontHandle _handle, const wchar_t* _string);
/// Preload a single glyph, return true on success
bool preloadGlyph(FontHandle _handle, CodePoint_t _character);
/// bake a font to disk (the set of preloaded glyph)
/// @return true if the baking succeed, false otherwise
bool saveBakedFont(FontHandle _handle, const char* _fontDirectory, const char* _fontName );
/// return the font descriptor of a font
/// @remark the handle is required to be valid
const FontInfo& getFontInfo(FontHandle _handle);
/// Return the rendering informations about the glyph region
/// Load the glyph from a TrueType font if possible
/// @return true if the Glyph is available
bool getGlyphInfo(FontHandle _handle, CodePoint_t _codePoint, GlyphInfo& _outInfo);
GlyphInfo& getBlackGlyph(){ return m_blackGlyph; }
class TrueTypeFont; //public to shut off Intellisense warning
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::HandleAlloc m_fontHandles;
CachedFont* m_cachedFonts;
bx::HandleAlloc m_filesHandles;
CachedFile* m_cachedFiles;
GlyphInfo m_blackGlyph;
//temporary buffer to raster glyph
uint8_t* m_buffer;
};
#endif // __FONT_MANAGER_H__