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@NogDogOct 15.2010 — #I'm sure it's probably "possible", but I'm not clear as to exactly what you want to do with the uploaded image, so I'm not sure how easy/difficult it would be. @NogDogOct 16.2010 — #Here's something using a resize function I already had lying around, which hopefully will give you some ideas:
Dynamic CSS sprites using GD?
I know this is probably impossible, but I want to generate sprites from user-uploaded images dynamically using PHP. Since my CSS file is already dynamically generated, I can add the appropriate CSS.
Please let me know as well if it’s not possible. Thanks ?
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@NogDogOct 15.2010 — #0
@NogDogOct 16.2010 — #Here's something using a resize function I already had lying around, which hopefully will give you some ideas:[code=php]
<?php
// TEST:
define('WIDTH', 200);
define('HEIGHT', 150);
$images = glob('images/*.png');
$thumb = resize(array_shift($images) , WIDTH, HEIGHT, $error) or die($error);
foreach($images as $img) {
$new = resize($img, WIDTH, HEIGHT, $error) or die($error);
$thumb = mergeThumbs($thumb, $new, WIDTH);
}
header('Content-Type: image/png');
imagepng($thumb);
// FUNCTIONS:
/**
* Resize image to specific dimension, cropping as needed
* @return resource Resized image resource, or boolean false on failure
* @param string $imgFile Path to image to be resized
* @param int $width
* @param int $height
* @param string $error Error message
*/
function resize($imgFile, $width, $height, &$error = null)
{
$attrs = @getimagesize($imgFile);
if ($attrs == false) {
$error = "Uploaded file does not appear to be an image ($imgFile)";
return false;
}
if ($attrs[0] * $attrs[1] > 3000000) {
$error = "Max pixels allowed is 3,000,000. Your {$attrs[0]} x " . "{$attrs[1]} image has " . $attrs[0] * $attrs[1] . " pixels.";
return false;
}
$ratio = (($attrs[0] / $attrs[1]) < ($width / $height)) ? $width / $attrs[0] : $height / $attrs[1];
$x = max(0, round($attrs[0] / 2 - ($width / 2) / $ratio));
$y = max(0, round($attrs[1] / 2 - ($height / 2) / $ratio));
switch ($attrs[2]) {
case IMAGETYPE_JPEG:
$src = @imagecreatefromjpeg($imgFile);
break;
case IMAGETYPE_PNG:
$src = @imagecreatefrompng($imgFile);
break;
case IMAGETYPE_GIF:
$src = @imagecreatefromgif($imgFile);
break;
default:
$error = "File is not a JPEG, PNG, or GIF image";
return false;
}
if ($src == false) {
$error = "An error occurred processing the file, it may have been corrupted.";
return false;
}
$resized = imagecreatetruecolor($width, $height);
$result = imagecopyresampled($resized, $src, 0, 0, $x, $y, $width, $height, round($width / $ratio, 0) , round($height / $ratio));
if ($result == false) {
$error = "Error trying to resize and crop image.";
return false;
} else {
return $resized;
}
}
/**
* Merge two thumbnails together
* @return resource
* @param resource $old
* @param resource $new
* @param int $width
*/
function mergeThumbs($old, $new, $width)
{
$heightOld = imagesy($old);
$heightNew = imagesy($new);
$heightMerged = $heightOld + $heightNew;
$imgMerged = imagecreatetruecolor($width, $heightMerged);
imagecopy($imgMerged, $old, 0, 0, 0, 0, $width, $heightOld);
imagecopy($imgMerged, $new, 0, $heightOld, 0, 0, $width, $heightNew);
return $imgMerged;
}
[/code]