public function pixelIndex(Int $x, Int $y) : Int
    {
        return imagecolorat($this->canvas, $x, $y);
    }
public function pixelIndex(Int $x, Int $y) : Int
    {
        return imagecolorat($this->canvas, $x, $y);
    }
public function pixelIndex ( Int $ x , Int $ y ) : Int { return imagecolorat ( $ this -> canvas , $ x , $ y ) ; }
Set pixel index

@param int $x
@param int $y

@return int
Set pixel index