internal/png/stdlibwriter.go
func opaque(m image.Image) bool {
	if o, ok := m.(opaquer); ok {
		return o.Opaque()
	}
	b := m.Bounds()
	for y := b.Min.Y; y < b.Max.Y; y++ {
		for x := b.Min.X; x < b.Max.X; x++ {
			_, _, _, a := m.At(x, y).RGBA()
			if a != 0xffff {
				return false
			}
		}
	}
	return true
}
func opaque(m image.Image) bool {
	if o, ok := m.(opaquer); ok {
		return o.Opaque()
	}
	b := m.Bounds()
	for y := b.Min.Y; y < b.Max.Y; y++ {
		for x := b.Min.X; x < b.Max.X; x++ {
			_, _, _, a := m.At(x, y).RGBA()
			if a != 0xffff {
				return false
			}
		}
	}
	return true
}
func opaque ( m image . Image ) bool { if o , ok := m . ( opaquer ) ; ok { return o . Opaque ( ) } b := m . Bounds ( ) for y := b . Min . Y ; y < b . Max . Y ; y ++ { for x := b . Min . X ; x < b . Max . X ; x ++ { _ , _ , _ , a := m . At ( x , y ) . RGBA ( ) if a != 0xffff { return false } } } return true }
// Returns whether or not the image is fully opaque.
Returns whether or not the image is fully opaque .