Drupal – Desaturate (black/white) an image using GD library

If u r using PHP GD library for image customization thn here’s a sample code for php developer to desaturate (black/white) an image using GD library.

if (!function_exists('webshopmodule_image_desaturate')) {
 function webshopmodule_image_desaturate($source, $destination) {
 $info = image_get_info($source);
 if (!$info) {
 return FALSE;
 }
 $width  = $info['width'];
 $height = $info['height'];

 $im = image_gd_open($source, $info['extension']);
 //$res = imageCreateTrueColor($width, $height);
 $res = @imagecreatetruecolor($width, $height);

 for ($y = 0; $y < $height; ++$y)
 for ($x = 0; $x < $width; ++$x) {
 $rgb = imagecolorat($im, $x, $y);
 $red   = ($rgb >> 16) & 0xFF;
 $green = ($rgb >> 8)  & 0xFF;
 $blue  = $rgb & 0xFF;

 $gray = round(.299*$red + .587*$green + .114*$blue);

 // shift gray level to the left
 $grayR = $gray << 16;   // R: red
 $grayG = $gray << 8;    // G: green
 $grayB = $gray;         // B: blue
 $grayColor = $grayR | $grayG | $grayB;

 // set the pixel color
 imagesetpixel($res, $x, $y, $grayColor);
 imagecolorallocate($res, $gray, $gray, $gray);
 }

 $result = image_gd_close($res, $destination, $info['extension']);

 imageDestroy($res);
 imageDestroy($im);

 return $result;
 }
}

// Here 'webshopmodule' is my module name