Resizing Uploaded Files - PHP
In this tutorial, I will teach you how to resize uploaded files to make them have either a fixed size, or a certain percent of its former size. The advantage of resizing uploaded files are many:
- The File's size would greatly reduce, enabling better performance.
- General fitness and a more elegant look especially for a photo gallery.
This tutorial requires the two plugins below:
- jQuery-1.5.1.min.js
- jQuery.form.js
- index.php
- upload.php
Index.php
<html><head>
<title>Ajax file upload with image resizing - Ohwofosirai Desmond</title>
<script type="text/javascript" src="jquery-1.5.1.min.js"></script>
<script type="text/javascript" src="jquery.form.js"></script>
<script>
$(document).ready(function() {
$('#uploader').live('change', function() {
$("#msg").html('');
$("#msg").text('Uploading....');
$("#upload").ajaxForm({
target: '#msg'
}).submit();
});
});
</script>
</head>
<body>
<DIV id="uploadfile" style="font-size:12px">
<div>
<p style="margin:2px; font-weight:bold; font-size:16px;">
Ajax file upload with image resizing.</p>
This ajax uploader uses the AjaxForm plugin.
</div>
<form id="upload" method="post" action="upload.php" enctype="multipart/form-data">
<p/><label>Upload profile picture</label>
<br/><input type="file" id="uploader" name="file"/>
</form>
<DIV id="msg"></DIV>
</DIV>
</body>
</html>
Upload.php - php image resizing
<?php/*initialize values($h=new height, $w=new width, $dir=storage location)*/
$h=60; $w=60;
extract($_POST);
//file format validation
$arr=array();
$valid_formats = array("jpg", "png", "gif", "bmp");
$filename=$_FILES['file']['name'];
$arr = explode(".",$filename);
$ext=$arr[count($arr)-1];
if(!in_array($ext, $valid_formats))
quit("Invalid file format");
//validate filesize
if ($_FILES['file']['size']>2048)
quit("File too large. Max: 2MB");
if(is_uploaded_file($_FILES['file']['tmp_name']))
move_uploaded_file($_FILES['file']['tmp_name'],"upload/".$filename);
//call function to resize and upload file
$resize=resize("upload/".$filename, "thumb/".$filename, 100);
if ($resize) quit('<img src="thumb/'.$filename.'" alt="image" id="msg"/>');
else quit('Unknown Error! Please Retry');
/*------------------------------------------------------------------------------------------
NOTE: This php function called "resize" had been copied from elsewhere on the internet.
help me if you have some info that can help me link them.
------------------------------------------------------------------------------------------*/
/* This function resizes an image by calculating percentage of new height using width specified.
resize(file_location, file_destination, new_width) */
function resize($orig_file,$thumb_file,$prop){
$img = $orig_file;
$constrain = true;
$w = $prop;
$h = $prop;
$percent=0;
// get image size of img
$x = @getimagesize($img);
// image width
$sw = $x[0];
// image height
$sh = $x[1];
if ($percent > 0) {
// calculate resized height and width if percent is defined
$percent = $percent * 0.01;
$w = $sw * $percent;
$h = $sh * $percent;
} else {
if (isset ($w) AND !isset ($h)) {
// autocompute height if only width is set
$h = (100 / ($sw / $w)) * .01;
$h = @round ($sh * $h);
} elseif (isset ($h) AND !isset ($w)) {
// autocompute width if only height is set
$w = (100 / ($sh / $h)) * .01;
$w = @round ($sw * $w);
} elseif (isset ($h) AND isset ($w) AND isset ($constrain)) {
// get the smaller resulting image dimension if both height
// and width are set and $constrain is also set
$hx = (100 / ($sw / $w)) * .01;
$hx = @round ($sh * $hx);
$wx = (100 / ($sh / $h)) * .01;
$wx = @round ($sw * $wx);
if ($hx < $h) {
$h = (100 / ($sw / $w)) * .01;
$h = @round ($sh * $h);
} else {
$w = (100 / ($sh / $h)) * .01;
$w = @round ($sw * $w);
}
}
}
$im = @ImageCreateFromJPEG ($img) or // Read JPEG Image
$im = @ImageCreateFromPNG ($img) or // or PNG Image
$im = @ImageCreateFromGIF ($img) or // or GIF Image
$im = false; // If image is not JPEG, PNG, or GIF
if (!$im) {
// We get errors from PHP's ImageCreate functions...
// So let's echo back the contents of the actual image.
readfile ($img);
} else {
// Create the resized image destination
$thumb = @ImageCreateTrueColor ($w, $h);
// Copy from image source, resize it, and paste to image destination
@ImageCopyResampled ($thumb, $im, 0, 0, 0, 0, $w, $h, $sw, $sh);
// Output resized image
@ImageJPEG ($thumb,$thumb_file);
}
return true;
}//resize function end here
//echo errors and quit, if any.
function quit($msg){
echo $msg;
exit;
}
?>
KEYWORDS: resize file php, file cropping, file php script
