the sporks space

I had some code trying to scale an image in gd using the imagescale function, that looked something like this:

/* makes a copy of the image, instead of modifying in place */
$target = imagescale($image, $width, $height);

However, the images it created were heavily distorted when using bilinear filtering, and didn’t quite look right with neared neighbour either. For example, with bilinear filtering…

It turns out I should have used the imagecopyresampled function instead with alpha blending options set:

$target = imagecreatetruecolor($width, $height);
imagealphablending($target, false);
imagesavealpha($target, true);
imagecopyresampled($target, $image, 0, 0, 0, 0, $width, $height, $old_width, $old_height);