add FontCache

This commit is contained in:
Achille Roussel 2015-11-18 14:59:19 -08:00
parent 9ffe0e7eb5
commit 598513aa60

91
font.go
View file

@ -6,7 +6,6 @@ package draw2d
import ( import (
"io/ioutil" "io/ioutil"
"log" "log"
"path"
"path/filepath" "path/filepath"
"github.com/golang/freetype/truetype" "github.com/golang/freetype/truetype"
@ -69,41 +68,89 @@ func FontFileName(fontData FontData) string {
} }
func RegisterFont(fontData FontData, font *truetype.Font) { func RegisterFont(fontData FontData, font *truetype.Font) {
fonts[fontNamer(fontData)] = font fontCache.Store(fontData, font)
} }
func GetFont(fontData FontData) *truetype.Font { func GetFont(fontData FontData) (font *truetype.Font) {
fontFileName := fontNamer(fontData) var err error
font := fonts[fontFileName]
if font != nil { if font, err = fontCache.Load(fontData); err != nil {
return font log.Println(err)
} }
fonts[fontFileName] = loadFont(fontFileName)
return fonts[fontFileName] return
} }
func GetFontFolder() string { func GetFontFolder() string {
return fontFolder return defaultFonts.folder
} }
func SetFontFolder(folder string) { func SetFontFolder(folder string) {
fontFolder = filepath.Clean(folder) defaultFonts.folder = filepath.Clean(folder)
} }
func SetFontNamer(fn FontFileNamer) { func SetFontNamer(fn FontFileNamer) {
fontNamer = fn defaultFonts.namer = fn
} }
func loadFont(fontFileName string) *truetype.Font { // Types implementing this interface can be passed to SetFontCache to change the
fontBytes, err := ioutil.ReadFile(path.Join(fontFolder, fontFileName)) // way fonts are being stored and retrieved.
if err != nil { type FontCache interface {
log.Println(err) // Loads a truetype font represented by the FontData object passed as
return nil // 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)
} }
font, err := truetype.Parse(fontBytes)
if err != nil { // Changes the font cache backend used by the package. After calling this
log.Println(err) // functionSetFontFolder and SetFontNamer will not affect anymore how fonts are
return nil // 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
} }
return font
} }
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
)