if n > len(p) {
		// Pad with black.
		clear(dst[3*len(p) : 3*n])
	}
	return 3 * n, nil
}

func (e *encoder) colorTablesMatch(localLen, transparentIndex int) bool {
	localSize := 3 * localLen
	if transparentIndex >= 0 {
		trOff := 3 * transparentIndex
		return bytes.Equal(e.globalColorTable[:trOff], e.localColorTable[:trOff]) &&
			bytes.Equal(e.globalColorTable[trOff+3:localSize], e.localColorTable[trOff+3:localSize])