Limbaje de Programare ( C++, Java, HTML, PHP, etc.)

<?php

//get the image variables from the url

//$image_source - the source of the image

$image_source = $_GET['image'];

//$max_width and $max_height are the maximum width and height of the image

$max_width = $_GET['w'];
$max_height = $_GET['h'];

//if there is an image

if($image_source!=""){

//the parameters for the image

$image_params = image_type($image_source);

//creat the image resource

$im = $image_params[1]($image_source);

//width and height of the image

$width = imagesx($im);
$height = imagesy($im);

//ratio to maximum width and height
//the larger ratio is the one that needs to be resized

$w_ratio = $width/$max_width;
$h_ratio = $height/$max_height;

//if the width ratio is larger

if($h_ratio<$w_ratio){

//resize the width to the max width

$wid = $max_width;

//resize the height proportionately

$heig = floor($height / $w_ratio);
$chng=1;
}

//if the height ratio is greater

elseif($h_ratio>$w_ratio){

//resize the height to the max height

$heig = $max_height;

//resize the width proportionately

$wid = floor($width / $h_ratio);
$chng=1;
}

//if the ratios are the same and the image needs to be smaller

elseif(($h_ratio==$w_ratio) && ($height>$max_height)){

//height is max height

$heig = $max_height;

//set width as a proportion using the height ratio

$wid = floor($width / $h_ratio);
$chng=1;


}

//if the ratios are the same and the image needs to be larger

elseif(($h_ratio==$w_ratio) && ($height<$max_height)){

//set the height and width as the max height and max width

$heig = $max_height;
$wid = $max_width;
$chng=1;

}

//if the sizes needed resizing

if($chng==1){

//create a new image resource

$resize_img = imagecreatetruecolor($wid,$heig);

//fill the image with white
$white = imagecolorallocate($resize_img,255,255,255);
imagefilledrectangle($resize_img,0,0,$wid,$heig,$white);

//copy the original image to the new image resource with the new size

imagecopyresampled($resize_img,$im,0,0,0,0,$wid,$heig,$width,$height);

//headers

header("$image_params[0]");

//send the image

$image_params[2]($resize_img);

//destroy the image

//modified thanks to randy's comment

imagedestroy($im);
imagedestroy($resize_img);
}

//if the image does not need resizing

else{

//headers

header("$image_params[0]");

//send the image

$image_params[2]($im);

//destroy the image
//modified thanks to randy's comment

imagedestroy($im);
}
}


/*
Creates an array of image values used above
$image_params[0] - the image headers
$image_params[1] - Creates the image
$image_params[2] - displays the image
*/

function image_type($v){

//find the filetype

$type = strtolower(strrchr($v,"."));

//depending what image file is used - different params are needed

switch($type){

case'.jpg':
$image_params = array("Content-type:image/jpeg",
"imagecreatefromjpeg","imagejpeg");
break;

case'.jpeg':
$image_params = array("Content-type:image/jpeg",
"imagecreatefromjpeg","imagejpeg");
break;

case'.gif':
$image_params = array("Content-type:image/gif",
"imagecreatefromgif","imagegif");
break;

case'.png':
$image_params = array("Content-type:image/png",
"imagecreatefrompng","imagepng");
break;

}

//return the image paramaters array

return($image_params);
}

?>