89 lines
2 KiB
Go
89 lines
2 KiB
Go
package draw2dbase
|
|
|
|
import (
|
|
"sync"
|
|
|
|
"github.com/llgcode/draw2d"
|
|
)
|
|
|
|
var glyphCache map[string]map[rune]*Glyph
|
|
var glyphCacheLock sync.RWMutex
|
|
|
|
func init() {
|
|
glyphCache = make(map[string]map[rune]*Glyph)
|
|
}
|
|
|
|
// 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 {
|
|
//fast parallel access with read-lock only
|
|
glyphCacheLock.RLock()
|
|
gCFont, _ := glyphCache[fontName]
|
|
if gCFont != nil {
|
|
gcRune, _ := gCFont[chr]
|
|
if gcRune != nil {
|
|
glyphCacheLock.RUnlock()
|
|
return gcRune
|
|
}
|
|
}
|
|
glyphCacheLock.RUnlock()
|
|
|
|
//cache miss requires write-lock
|
|
glyphCacheLock.Lock()
|
|
defer glyphCacheLock.Unlock()
|
|
|
|
if glyphCache[fontName] == nil {
|
|
glyphCache[fontName] = make(map[rune]*Glyph, 60)
|
|
}
|
|
if glyphCache[fontName][chr] == nil {
|
|
glyphCache[fontName][chr] = renderGlyph(gc, fontName, chr)
|
|
}
|
|
return glyphCache[fontName][chr].Copy()
|
|
}
|
|
|
|
// renderGlyph renders a glyph then caches and returns it
|
|
func renderGlyph(gc draw2d.GraphicContext, fontName string, chr rune) *Glyph {
|
|
gc.Save()
|
|
defer gc.Restore()
|
|
gc.BeginPath()
|
|
width := gc.CreateStringPath(string(chr), 0, 0)
|
|
path := gc.GetPath()
|
|
return &Glyph{
|
|
path: &path,
|
|
Width: width,
|
|
}
|
|
}
|
|
|
|
// 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
|
|
}
|
|
|
|
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
|
|
}
|