Question

So I already know how to combine two images and keep transparency using the GD image library with php however I need to be able to pull images from the server while keeping the dimensions in the power of two so that I can use them as textures to be applied to 3d objects in opengl.

So my real question is how can I place a scaled version of an image that keeps its original proportions within a transparent one that has a 256×256 or 128×128 dimension. Also Id like to place the resized image within the center of the completely transparent one.

Some help on this would be awesome.

Answer 1

Check out this references, I think it’s what you want: http://php.net/manual/en/function.imagecopyresized.php

<?php
// File and new size
$filename = 'test.jpg';
$percent = 0.5;

// Content type
header('Content-Type: image/jpeg');

// Get new sizes
list($width, $height) = getimagesize($filename);
$newwidth = $width * $percent;
$newheight = $height * $percent;

// Load
$thumb = imagecreatetruecolor($newwidth, $newheight);
$source = imagecreatefromjpeg($filename);

// Resize
imagecopyresized($thumb, $source, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);

// Output
imagejpeg($thumb);
?>