\ZxingGDLuminanceSource

<?php


namespace Zxing;

/**
 * This class is used to help decode images from files which arrive as GD Resource
 * It does not support rotation.
 *
 *
 *
 */
final class GDLuminanceSource extends LuminanceSource {

    public   $luminances;
    private  $dataWidth;
    private  $dataHeight;
    private  $left;
    private  $top;
    private  $gdImage;



    public function __construct($gdImage,
                                $dataWidth,
                                $dataHeight,
                                $left=null,
                                $top=null,
                                $width=null,
                                $height=null) {
        if(!$left&&!$top&&!$width&&!$height){
            $this->GDLuminanceSource($gdImage,$dataWidth,$dataHeight);
            return;
        }
        parent::__construct($width, $height);
        if ($left + $width > $dataWidth || $top + $height > $dataHeight) {
            throw new \InvalidArgumentException("Crop rectangle does not fit within image data.");
        }
        $this->luminances = $gdImage;
        $this->dataWidth = $dataWidth;
        $this->dataHeight = $dataHeight;
        $this->left = $left;
        $this->top = $top;
    }

    public function GDLuminanceSource($gdImage, $width, $height)
    {
        parent::__construct($width, $height);

        $this->dataWidth = $width;
        $this->dataHeight = $height;
        $this->left = 0;
        $this->top = 0;
        $this->$gdImage = $gdImage;


// In order to measure pure decoding speed, we convert the entire image to a greyscale array
// up front, which is the same as the Y channel of the YUVLuminanceSource in the real app.
        $this->luminances = array();
        //$this->luminances = $this->grayScaleToBitmap($this->grayscale());

        $array = array();
        $rgb = array();

for($j=0;$j<$height;$j++){
    for($i=0;$i<$width;$i++){
        $argb = imagecolorat($this->$gdImage, $i, $j);
        $pixel = imagecolorsforindex($this->$gdImage, $argb);
        $r = $pixel['red'];
        $g = $pixel['green'];
        $b = $pixel['blue'];
        if ($r == $g && $g == $b) {
// Image is already greyscale, so pick any channel.

            $this->luminances[] = $r;//(($r + 128) % 256) - 128;
        } else {
// Calculate luminance cheaply, favoring green.
            $this->luminances[] = ($r+2*$g+$b)/4;//(((($r + 2 * $g + $b) / 4) + 128) % 256) - 128;
        }
    }
}



        /*

        for ($y = 0; $y < $height; $y++) {
            $offset = $y * $width;
            for ($x = 0; $x < $width; $x++) {
                $pixel = $pixels[$offset + $x];
                $r = ($pixel >> 16) & 0xff;
                $g = ($pixel >> 8) & 0xff;
                $b = $pixel & 0xff;
                if ($r == $g && $g == $b) {
// Image is already greyscale, so pick any channel.

                    $this->luminances[intval($offset + $x)] = (($r+128) % 256) - 128;
                } else {
// Calculate luminance cheaply, favoring green.
                    $this->luminances[intval($offset + $x)] =  (((($r + 2 * $g + $b) / 4)+128)%256) - 128;
                }



            }
        */
        //}
        //   $this->luminances = $this->grayScaleToBitmap($this->luminances);

    }

//@Override
    public function getRow($y, $row=null) {
        if ($y < 0 || $y >= $this->getHeight()) {
            throw new \InvalidArgumentException("Requested row is outside the image: " + y);
        }
        $width = $this->getWidth();
        if ($row == null || count($row) < $width) {
            $row = array();
        }
        $offset = ($y + $this->top) * $this->dataWidth + $this->left;
        $row = arraycopy($this->luminances,$offset, $row, 0, $width);
        return $row;
    }

//@Override
    public function getMatrix() {
        $width = $this->getWidth();
        $height = $this->getHeight();

// If the caller asks for the entire underlying image, save the copy and give them the
// original data. The docs specifically warn that result.length must be ignored.
        if ($width == $this->dataWidth && $height == $this->dataHeight) {
            return $this->luminances;
        }

        $area = $width * $height;
        $matrix = array();
        $inputOffset = $this->top * $this->dataWidth + $this->left;

// If the width matches the full width of the underlying data, perform a single copy.
        if ($width == $this->dataWidth) {
            $matrix = arraycopy($this->luminances, $inputOffset, $matrix, 0, $area);
            return $matrix;
        }

// Otherwise copy one cropped row at a time.
        $rgb = $this->luminances;
        for ($y = 0; $y < $height; $y++) {
            $outputOffset = $y * $width;
            $matrix = arraycopy($rgb, $inputOffset, $matrix, $outputOffset, $width);
            $inputOffset += $this->dataWidth;
        }
        return $matrix;
    }

//@Override
    public function isCropSupported() {
        return true;
    }

//@Override
    public function crop($left, $top, $width, $height) {
        return new GDLuminanceSource($this->luminances,
            $this->dataWidth,
            $this->dataHeight,
            $this->left + $left,
            $this->top + $top,
            $width,
            $height);
    }

}