Just a little script to create a PNG image of a simple linear gradient using PHP. You could adapt this to make it better in many ways! Insipired (by which I mean 99% ripped of!) by http://www.cutcodedown.com/

No demo to avoid load on the server, but it just makes a simple gradient.

I use it as a fallback for CSS3 gradients.

> 16) & 0xFF;
	$g=($startColor >> 8) & 0xFF;
	$b=($startColor) & 0xFF;
	
	if ($height==0) {
		imagefill($final,0,0,imagecolorallocate($final,$r,$g,$b));
	} else {
		
		$endR=($endColor >> 16) & 0xFF;
		$endG=($endColor >> 8) & 0xFF;
		$endB=($endColor) & 0xFF;
		
		$incR=($endR-$r);
		$incG=($endG-$g);
		$incB=($endB-$b);
		
		$absDisR=abs($incR);
		$absDisG=abs($incG);
		$absDisB=abs($incB);
		
		if ($absDisR>$absDisG) {
			if ($absDisR>$absDisB) {
				$distance=$absDisR;
			} else {
				$distance=$absDisB;
			}
		} else if ($absDisG>$absDisB) {
			$distance=$absDisG;
		} else {
			$distance=$absDisB;
		}
		
		if ($distance==0) {
			imagefill($final,0,0,imagecolorallocate($final,$r,$g,$b));
		} else {
			if ($distance>$height) $distance=$height;
			
			$sliver=imagecreatetruecolor(1,$distance);
			$sliverMax=$distance-1;
			
			$incR/=$sliverMax;
			$incG/=$sliverMax;
			$incB/=$sliverMax;
			
			$style=array();
		
			for ($t=0; $t<$distance; $t++) {
				$style[$t]=imagecolorallocate($sliver,$r,$g,$b);
				$r+=$incR;
				$g+=$incG;
				$b+=$incB;
			}
			
			imagesetstyle($sliver,$style);
			imageline($sliver,0,0,0,$sliverMax,IMG_COLOR_STYLED);
			imagecopyresized(
				$final,$sliver,
				0,0,0,0,
				$width,$height,1,$distance
			);
			imagedestroy($sliver);
		}
	}
	return $final;
}

/* This bit isn't really very good, but you get the idea. */
$width=is_numeric(str_replace("px","",$_GET['w'])) ? $_GET['w'] : 96;
$height=is_numeric(str_replace("px","",$_GET['h'])) ? $_GET['h'] : 96;
$startColor=empty($_GET['sc']) ? 0 : hexdec($_GET['sc']);
$endColor=empty($_GET['ec']) ? 0xFFFFFF : hexdec($_GET['ec']);

$filename = $width."_".$height."_".$_GET['sc']."_".$_GET['ec'].".png";

if (!file_exists($destfolder.$filename)) {
	$image=gradient($width,$height,$startColor,$endColor);
	imagepng($image,$destfolder.$filename);
	imagedestroy($image);
}

caching_headers ($filename, filemtime($destfolder.$filename));

header('Parameters : '.$_GET['w']."x".$_GET['h']." ".$_GET['sc']." to ".$_GET['ec']);
header('Content-Type: image/png');

$image = imagecreatefrompng($destfolder.$filename);	
imagepng($image);
imagedestroy($image);
	
?>