facecachel.go

package fontutil

import (
	"image"
	"sync"

	"golang.org/x/image/font"
	"golang.org/x/image/math/fixed"
)

// Same as FaceCache but with locks.
type FaceCacheL struct {
	font.Face
	mu  sync.RWMutex
	gc  map[rune]*GlyphCache
	gac map[rune]*GlyphAdvanceCache
	gbc map[rune]*GlyphBoundsCache
	kc  map[string]fixed.Int26_6 // kern cache
}

func NewFaceCacheL(face font.Face) *FaceCacheL {
	fc := &FaceCacheL{Face: face}
	fc.gc = make(map[rune]*GlyphCache)
	fc.gac = make(map[rune]*GlyphAdvanceCache)
	fc.gbc = make(map[rune]*GlyphBoundsCache)
	fc.kc = make(map[string]fixed.Int26_6)
	return fc
}
func (fc *FaceCacheL) Glyph(dot fixed.Point26_6, ru rune) (
	dr image.Rectangle,
	mask image.Image,
	maskp image.Point,
	advance fixed.Int26_6,
	ok bool,
) {
	fc.mu.RLock()
	gc, ok := fc.gc[ru]
	fc.mu.RUnlock()
	if !ok {
		fc.mu.Lock()
		gc = NewGlyphCache(fc.Face, ru)
		fc.gc[ru] = gc
		fc.mu.Unlock()
	}
	p := image.Point{dot.X.Floor(), dot.Y.Floor()}
	dr2 := gc.dr.Add(p)
	return dr2, gc.mask, gc.maskp, gc.advance, gc.ok
}
func (fc *FaceCacheL) GlyphAdvance(ru rune) (advance fixed.Int26_6, ok bool) {
	fc.mu.RLock()
	gac, ok := fc.gac[ru]
	fc.mu.RUnlock()
	if !ok {
		fc.mu.Lock()
		gac = NewGlyphAdvanceCache(fc.Face, ru)
		fc.gac[ru] = gac
		fc.mu.Unlock()
	}
	return gac.advance, gac.ok
}
func (fc *FaceCacheL) GlyphBounds(ru rune) (bounds fixed.Rectangle26_6, advance fixed.Int26_6, ok bool) {
	fc.mu.RLock()
	gbc, ok := fc.gbc[ru]
	fc.mu.RUnlock()
	if !ok {
		fc.mu.Lock()
		gbc = NewGlyphBoundsCache(fc.Face, ru)
		fc.gbc[ru] = gbc
		fc.mu.Unlock()
	}
	return gbc.bounds, gbc.advance, gbc.ok
}
func (fc *FaceCacheL) Kern(r0, r1 rune) fixed.Int26_6 {
	i := kernIndex(r0, r1)
	fc.mu.RLock()
	k, ok := fc.kc[i]
	fc.mu.RUnlock()
	if !ok {
		fc.mu.Lock()
		k = NewKernCache(fc.Face, r0, r1)
		fc.kc[i] = k
		fc.mu.Unlock()
	}
	return k
}