draw2d/draw2dbase/text.go
2018-11-16 12:21:14 +01:00

82 lines
2.1 KiB
Go

package draw2dbase
import "git.fromouter.space/crunchy-rocks/draw2d"
// GlyphCache manage a cache of glyphs
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
}
// GlyphCacheImp manage a map of glyphs without sync mecanism, not thread safe
type GlyphCacheImp struct {
glyphs map[string]map[rune]*Glyph
}
// NewGlyphCache initializes a GlyphCache
func NewGlyphCache() *GlyphCacheImp {
glyphs := make(map[string]map[rune]*Glyph)
return &GlyphCacheImp{
glyphs: glyphs,
}
}
// Fetch fetches a glyph from the cache, calling renderGlyph first if it doesn't already exist
func (glyphCache *GlyphCacheImp) Fetch(gc draw2d.GraphicContext, fontName string, chr rune) *Glyph {
if glyphCache.glyphs[fontName] == nil {
glyphCache.glyphs[fontName] = make(map[rune]*Glyph, 60)
}
if glyphCache.glyphs[fontName][chr] == nil {
glyphCache.glyphs[fontName][chr] = renderGlyph(gc, fontName, chr)
}
return glyphCache.glyphs[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
}
// Copy Returns a copy of a Glyph
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
}