diff --git a/font.go b/font.go index b9b0092..81696c9 100644 --- a/font.go +++ b/font.go @@ -6,7 +6,6 @@ package draw2d import ( "io/ioutil" "log" - "path" "path/filepath" "github.com/golang/freetype/truetype" @@ -69,41 +68,89 @@ func FontFileName(fontData FontData) string { } func RegisterFont(fontData FontData, font *truetype.Font) { - fonts[fontNamer(fontData)] = font + fontCache.Store(fontData, font) } -func GetFont(fontData FontData) *truetype.Font { - fontFileName := fontNamer(fontData) - font := fonts[fontFileName] - if font != nil { - return font +func GetFont(fontData FontData) (font *truetype.Font) { + var err error + + if font, err = fontCache.Load(fontData); err != nil { + log.Println(err) } - fonts[fontFileName] = loadFont(fontFileName) - return fonts[fontFileName] + + return } func GetFontFolder() string { - return fontFolder + return defaultFonts.folder } func SetFontFolder(folder string) { - fontFolder = filepath.Clean(folder) + defaultFonts.folder = filepath.Clean(folder) } func SetFontNamer(fn FontFileNamer) { - fontNamer = fn + defaultFonts.namer = fn } -func loadFont(fontFileName string) *truetype.Font { - fontBytes, err := ioutil.ReadFile(path.Join(fontFolder, fontFileName)) - if err != nil { - log.Println(err) - return nil - } - font, err := truetype.Parse(fontBytes) - if err != nil { - log.Println(err) - return nil - } - return font +// Types implementing this interface can be passed to SetFontCache to change the +// way fonts are being stored and retrieved. +type FontCache interface { + // Loads a truetype font represented by the FontData object passed as + // argument. + // The method returns an error if the font could not be loaded, either + // because it didn't exist or the resource it was loaded from was corrupted. + Load(FontData) (*truetype.Font, error) + + // Sets the truetype font that will be returned by Load when given the font + // data passed as first argument. + Store(FontData, *truetype.Font) } + +// Changes the font cache backend used by the package. After calling this +// functionSetFontFolder and SetFontNamer will not affect anymore how fonts are +// loaded. +// To restore the default font cache, call this function passing nil as argument. +func SetFontCache(cache FontCache) { + if cache == nil { + fontCache = defaultFonts + } else { + fontCache = cache + } +} + +type defaultFontCache struct { + fonts map[string]*truetype.Font + folder string + namer FontFileNamer +} + +func (cache *defaultFontCache) Load(fontData FontData) (font *truetype.Font, err error) { + var data []byte + var file = cache.namer(fontData) + + if data, err = ioutil.ReadFile(filepath.Join(cache.folder, file)); err != nil { + return + } + + if font, err = truetype.Parse(data); err != nil { + return + } + + cache.fonts[file] = font + return +} + +func (cache *defaultFontCache) Store(fontData FontData, font *truetype.Font) { + cache.fonts[cache.namer(fontData)] = font +} + +var ( + defaultFonts = &defaultFontCache{ + fonts: make(map[string]*truetype.Font), + folder: "../resource/font", + namer: FontFileName, + } + + fontCache FontCache = defaultFonts +)