PHP GD Grayscale
This example shows how to Grayscale an image in php gd.
This example shows how to Grayscale an image in php gd.<?php
$file = 'images.jpg';
header('Content-type: image/jpeg');
list($width, $height) = getimagesize($file);
$source = imagecreatefromjpeg($file);
$bwimage= imagecreate($width, $height);
for ($c=0;$c<256;$c++)
{
$palette[$c] = imagecolorallocate($bwimage,$c,$c,$c);
}
function yiq($r,$g,$b)
{
return (($r*0.299)+($g*0.587)+($b*0.114));
}
for ($y=0;$y<$height;$y++)
{
for ($x=0;$x<$width;$x++)
{
$rgb = imagecolorat($source,$x,$y);
$r = ($rgb >> 16) & 0xFF;
$g = ($rgb >> 8) & 0xFF;
$b = $rgb & 0xFF;
$gs = yiq($r,$g,$b);
imagesetpixel($bwimage,$x,$y,$palette[$gs]);
}
}
imagejpeg($bwimage);
?>
After running the program you will get the following output
