draw2d/draw2dbase/text.go

68 lines
1.6 KiB
Go

package draw2dbase
import "github.com/llgcode/draw2d"
var glyphCache map[string]map[rune]*Glyph
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 {
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
}