Made the GlyphCache settable per GraphicContext

draw2dbase/stack_gc.go

@@ -32,6 +32,7 @@ type ContextStack struct {
 	Join        draw2d.LineJoin
 	FontSize    float64
 	FontData    draw2d.FontData
+	GlyphCache  draw2d.GlyphCache
 
 	Font *truetype.Font
 	// fontSize and dpi are used to calculate scale. scale is the number of
@@ -57,6 +58,7 @@ func NewStackGraphicContext() *StackGraphicContext {
 	gc.Current.Join = draw2d.RoundJoin
 	gc.Current.FontSize = 10
 	gc.Current.FontData = DefaultFontData
+	gc.Current.GlyphCache = DefaultGlyphCache
 	return gc
 }
 
@@ -169,6 +171,21 @@ func (gc *StackGraphicContext) Close() {
 	gc.Current.Path.Close()
 }
 
+// Changes the glyph cache backend used by the GraphicContext.
+// To restore the default glyph cache, call this function passing nil as argument.
+func (gc *StackGraphicContext) SetGlyphCache(cache draw2d.GlyphCache) {
+	if cache == nil {
+		gc.Current.GlyphCache = DefaultGlyphCache
+	} else {
+		gc.Current.GlyphCache = cache
+	}
+}
+
+// Gets the glyph cache backend used by the GraphicContext.
+func (gc *StackGraphicContext) GetGlyphCache() draw2d.GlyphCache {
+	return gc.Current.GlyphCache
+}
+
 func (gc *StackGraphicContext) Save() {
 	context := new(ContextStack)
 	context.FontSize = gc.Current.FontSize
@@ -184,6 +201,7 @@ func (gc *StackGraphicContext) Save() {
 	context.Path = gc.Current.Path.Copy()
 	context.Font = gc.Current.Font
 	context.Scale = gc.Current.Scale
+	context.GlyphCache = gc.Current.GlyphCache
 	copy(context.Tr[:], gc.Current.Tr[:])
 	context.Previous = gc.Current
 	gc.Current = context

draw2dbase/text.go

@@ -3,38 +3,17 @@ package draw2dbase
 import "github.com/llgcode/draw2d"
 
 var (
-	glyphCacheDefault            = &defaultGlyphCache{make(map[string]map[rune]*Glyph)}
-	glyphCache        GlyphCache = glyphCacheDefault
+	DefaultGlyphCache = &defaultGlyphCache{make(map[string]map[rune]*draw2d.Glyph)}
 )
 
-// Types implementing this interface can be passed to SetGlyphCache to change the
-// way glyphs are being stored and retrieved.
-type GlyphCache interface {
-	// Fetch fetches a glyph from the cache, storing with Render first if it doesn't already exist
-	Fetch(gc draw2d.GraphicContext, fontName string, chr rune) *Glyph
-
-	// Render renders a glyph then returns it
-	Render(gc draw2d.GraphicContext, fontName string, chr rune) *Glyph
-}
-
-// Changes the glyph cache backend used by the package.
-// To restore the default glyph cache, call this function passing nil as argument.
-func SetGlyphCache(cache GlyphCache) {
-	if cache == nil {
-		glyphCache = glyphCacheDefault
-	} else {
-		glyphCache = cache
-	}
-}
-
 type defaultGlyphCache struct {
-	glyphMap map[string]map[rune]*Glyph
+	glyphMap map[string]map[rune]*draw2d.Glyph
 }
 
 // Fetch fetches a glyph from the cache, storing with Render first if it doesn't already exist
-func (cache *defaultGlyphCache) Fetch(gc draw2d.GraphicContext, fontName string, chr rune) *Glyph {
+func (cache *defaultGlyphCache) Fetch(gc draw2d.GraphicContext, fontName string, chr rune) *draw2d.Glyph {
 	if cache.glyphMap[fontName] == nil {
-		cache.glyphMap[fontName] = make(map[rune]*Glyph, 60)
+		cache.glyphMap[fontName] = make(map[rune]*draw2d.Glyph, 60)
 	}
 	if cache.glyphMap[fontName][chr] == nil {
 		cache.glyphMap[fontName][chr] = cache.Render(gc, fontName, chr)
@@ -43,60 +22,24 @@ func (cache *defaultGlyphCache) Fetch(gc draw2d.GraphicContext, fontName string,
 }
 
 // Render renders a glyph then returns it
-func (cache *defaultGlyphCache) Render(gc draw2d.GraphicContext, fontName string, chr rune) *Glyph {
+func (cache *defaultGlyphCache) Render(gc draw2d.GraphicContext, fontName string, chr rune) *draw2d.Glyph {
 	gc.Save()
 	defer gc.Restore()
 	gc.BeginPath()
 	width := gc.CreateStringPath(string(chr), 0, 0)
 	path := gc.GetPath()
-	return &Glyph{
-		path:  &path,
+	return &draw2d.Glyph{
+		Path:  &path,
 		Width: width,
 	}
 }
 
 // FetchGlyph fetches a glyph from the cache, calling renderGlyph first if it doesn't already exist
-func FetchGlyph(gc draw2d.GraphicContext, fontName string, chr rune) *Glyph {
-	return glyphCache.Fetch(gc, fontName, chr)
+func FetchGlyph(gc draw2d.GraphicContext, fontName string, chr rune) *draw2d.Glyph {
+	return gc.GetGlyphCache().Fetch(gc, fontName, chr)
 }
 
 // renderGlyph renders a glyph then caches and returns it
-func renderGlyph(gc draw2d.GraphicContext, fontName string, chr rune) *Glyph {
-	return glyphCache.Render(gc, fontName, chr)
-}
-
-// Glyph represents a rune which has been converted to a Path and width
-type Glyph struct {
-	// path represents a glyph, it is always at (0, 0)
-	path *draw2d.Path
-	// Width of the glyph
-	Width float64
-}
-
-// Copy copys the Glyph, and returns the copy
-func (g *Glyph) Copy() *Glyph {
-	return &Glyph{
-		path:  g.path.Copy(),
-		Width: g.Width,
-	}
-}
-
-// Fill copies a glyph from the cache, and fills it
-func (g *Glyph) Fill(gc draw2d.GraphicContext, x, y float64) float64 {
-	gc.Save()
-	gc.BeginPath()
-	gc.Translate(x, y)
-	gc.Fill(g.path)
-	gc.Restore()
-	return g.Width
-}
-
-// Stroke fetches a glyph from the cache, and strokes it
-func (g *Glyph) Stroke(gc draw2d.GraphicContext, x, y float64) float64 {
-	gc.Save()
-	gc.BeginPath()
-	gc.Translate(x, y)
-	gc.Stroke(g.path)
-	gc.Restore()
-	return g.Width
+func renderGlyph(gc draw2d.GraphicContext, fontName string, chr rune) *draw2d.Glyph {
+	return gc.GetGlyphCache().Render(gc, fontName, chr)
 }

gc.go

@@ -52,6 +52,10 @@ type GraphicContext interface {
 	GetFontData() FontData
 	// GetFontName gets the current FontData as a string
 	GetFontName() string
+	// SetGlyphCache changes the glyph cache backend used by the GraphicContext
+	SetGlyphCache(cache GlyphCache)
+	// GetGlyphCache gets the current GlyphCache
+	GetGlyphCache() GlyphCache
 	// DrawImage draws the raster image in the current canvas
 	DrawImage(image image.Image)
 	// Save the context and push it to the context stack

glyph.go

@@ -0,0 +1,47 @@
+package draw2d
+
+// Types implementing this interface can be passed to gc.SetGlyphCache to change the
+// way glyphs are being stored and retrieved.
+type GlyphCache interface {
+	// Fetch fetches a glyph from the cache, storing with Render first if it doesn't already exist
+	Fetch(gc GraphicContext, fontName string, chr rune) *Glyph
+
+	// Render renders a glyph then returns it
+	Render(gc GraphicContext, fontName string, chr rune) *Glyph
+}
+
+// Glyph represents a rune which has been converted to a Path and width
+type Glyph struct {
+	// Path represents a glyph, it is always at (0, 0)
+	Path *Path
+	// Width of the glyph
+	Width float64
+}
+
+// Copy copys the Glyph, and returns the copy
+func (g *Glyph) Copy() *Glyph {
+	return &Glyph{
+		Path:  g.Path.Copy(),
+		Width: g.Width,
+	}
+}
+
+// Fill fills a Glyph in the specified coordinates
+func (g *Glyph) Fill(gc GraphicContext, x, y float64) float64 {
+	gc.Save()
+	gc.BeginPath()
+	gc.Translate(x, y)
+	gc.Fill(g.Path)
+	gc.Restore()
+	return g.Width
+}
+
+// Stroke strokes a Glyph in the specified coordinates
+func (g *Glyph) Stroke(gc GraphicContext, x, y float64) float64 {
+	gc.Save()
+	gc.BeginPath()
+	gc.Translate(x, y)
+	gc.Stroke(g.Path)
+	gc.Restore()
+	return g.Width
+}