shareable: Add MakeVolatile

image.go

@@ -66,12 +66,10 @@ func (m *mipmap) level(r image.Rectangle, level int) *shareable.Image {
 		if w2 == 0 || h2 == 0 {
 			return nil
 		}
-		var s *shareable.Image
+		s := shareable.NewImage(w2, h2)
 		if m.orig.IsVolatile() {
 			// TODO: As s is cleared every frame, is there any reason to keep it?
-			s = shareable.NewVolatileImage(w2, h2)
-		} else {
-			s = shareable.NewImage(w2, h2)
+			s.MakeVolatile()
 		}
 
 		var src *shareable.Image
@@ -743,8 +741,10 @@ func NewImage(width, height int, filter Filter) (*Image, error) {
 //
 // If width or height is less than 1 or more than device-dependent maximum size, newVolatileImage panics.
 func newVolatileImage(width, height int) *Image {
+	s := shareable.NewImage(width, height)
+	s.MakeVolatile()
 	i := &Image{
-		mipmap: newMipmap(shareable.NewVolatileImage(width, height)),
+		mipmap: newMipmap(s),
 	}
 	i.addr = i
 	runtime.SetFinalizer(i, (*Image).Dispose)

internal/shareable/shareable.go

@@ -481,22 +481,13 @@ func (i *Image) allocate(shareable bool) {
 	return
 }
 
-func NewVolatileImage(width, height int) *Image {
+func (i *Image) MakeVolatile() {
 	backendsM.Lock()
 	defer backendsM.Unlock()
 
-	r := restorable.NewImage(width, height)
-	r.MakeVolatile()
-	i := &Image{
-		width:  width,
-		height: height,
-		backend: &backend{
-			restorable: r,
-		},
-		neverShared: true,
-	}
-	runtime.SetFinalizer(i, (*Image).Dispose)
-	return i
+	i.ensureNotShared()
+	i.backend.restorable.MakeVolatile()
+	i.neverShared = true
 }
 
 func NewScreenFramebufferImage(width, height int) *Image {

internal/shareable/shareable_test.go

@@ -140,7 +140,8 @@ func Disabled_TestReshared(t *testing.T) {
 	}
 	img2.ReplacePixels(pix)
 
-	img3 := NewVolatileImage(size, size)
+	img3 := NewImage(size, size)
+	img3.MakeVolatile()
 	defer img3.Dispose()
 	img1.ReplacePixels(make([]byte, 4*size*size))
 	want = false