155 lines
3.3 KiB
Go
155 lines
3.3 KiB
Go
// Copyright 2010 The draw2d Authors. All rights reserved.
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// created: 13/12/2010 by Laurent Le Goff
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package draw2d
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import (
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"io/ioutil"
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"log"
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"path/filepath"
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"github.com/golang/freetype/truetype"
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)
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// FontStyle defines bold and italic styles for the font
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// It is possible to combine values for mixed styles, eg.
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// FontData.Style = FontStyleBold | FontStyleItalic
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type FontStyle byte
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const (
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FontStyleNormal FontStyle = iota
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FontStyleBold
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FontStyleItalic
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)
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type FontFamily byte
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const (
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FontFamilySans FontFamily = iota
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FontFamilySerif
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FontFamilyMono
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)
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type FontData struct {
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Name string
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Family FontFamily
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Style FontStyle
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}
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type FontFileNamer func(fontData FontData) string
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func FontFileName(fontData FontData) string {
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fontFileName := fontData.Name
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switch fontData.Family {
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case FontFamilySans:
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fontFileName += "s"
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case FontFamilySerif:
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fontFileName += "r"
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case FontFamilyMono:
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fontFileName += "m"
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}
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if fontData.Style&FontStyleBold != 0 {
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fontFileName += "b"
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} else {
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fontFileName += "r"
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}
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if fontData.Style&FontStyleItalic != 0 {
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fontFileName += "i"
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}
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fontFileName += ".ttf"
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return fontFileName
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}
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func RegisterFont(fontData FontData, font *truetype.Font) {
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fontCache.Store(fontData, font)
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}
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func GetFont(fontData FontData) (font *truetype.Font) {
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var err error
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if font, err = fontCache.Load(fontData); err != nil {
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log.Println(err)
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}
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return
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}
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func GetFontFolder() string {
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return defaultFonts.folder
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}
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func SetFontFolder(folder string) {
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defaultFonts.folder = filepath.Clean(folder)
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}
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func SetFontNamer(fn FontFileNamer) {
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defaultFonts.namer = fn
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}
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// Types implementing this interface can be passed to SetFontCache to change the
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// way fonts are being stored and retrieved.
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type FontCache interface {
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// Loads a truetype font represented by the FontData object passed as
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// argument.
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// The method returns an error if the font could not be loaded, either
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// because it didn't exist or the resource it was loaded from was corrupted.
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Load(FontData) (*truetype.Font, error)
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// Sets the truetype font that will be returned by Load when given the font
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// data passed as first argument.
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Store(FontData, *truetype.Font)
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}
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// Changes the font cache backend used by the package. After calling this
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// functionSetFontFolder and SetFontNamer will not affect anymore how fonts are
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// loaded.
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// To restore the default font cache, call this function passing nil as argument.
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func SetFontCache(cache FontCache) {
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if cache == nil {
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fontCache = defaultFonts
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} else {
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fontCache = cache
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}
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}
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type defaultFontCache struct {
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fonts map[string]*truetype.Font
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folder string
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namer FontFileNamer
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}
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func (cache *defaultFontCache) Load(fontData FontData) (font *truetype.Font, err error) {
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if font = cache.fonts[cache.namer(fontData)]; font != nil {
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return font, nil
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}
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var data []byte
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var file = cache.namer(fontData)
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if data, err = ioutil.ReadFile(filepath.Join(cache.folder, file)); err != nil {
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return
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}
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if font, err = truetype.Parse(data); err != nil {
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return
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}
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cache.fonts[file] = font
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return
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}
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func (cache *defaultFontCache) Store(fontData FontData, font *truetype.Font) {
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cache.fonts[cache.namer(fontData)] = font
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}
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var (
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defaultFonts = &defaultFontCache{
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fonts: make(map[string]*truetype.Font),
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folder: "../resource/font",
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namer: FontFileName,
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}
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fontCache FontCache = defaultFonts
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)
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