"image/draw"
	"internal/byteorder"
	"io"
)

// Graphic control extension fields.
const (
	gcLabel     = 0xF9
	gcBlockSize = 0x04
)

var log2Lookup = [8]int{2, 4, 8, 16, 32, 64, 128, 256}

func log2(x int) int {
	for i, v := range log2Lookup {
		if x <= v {
			return i
		}
	}
	return -1
}

// writer is a buffered writer.
type writer interface {
	Flush() error
	io.Writer