Php image thumbnail generation script

http://www.reconn.us/image_thumbnail.html

Start of script...

<?php //define a maxim size for the uploaded images define ("MAX_SIZE","100"); // define the width and height for the thumbnail // note that theese dimmensions are considered the maximum dimmension and are not fixed, // because we have to keep the image ratio intact or it will be deformed define ("WIDTH","150"); define ("HEIGHT","100");

// this is the function that will create the thumbnail image from the uploaded image // the resize will be done considering the width and height defined, but without deforming the image function make_thumb($img_name,$filename,$new_w,$new_h) { //get image extension. $ext=getExtension($img_name); //creates the new image using the appropriate function from gd library if(!strcmp("jpg",$ext) || !strcmp("jpeg",$ext)) $src_img=imagecreatefromjpeg($img_name);

if(!strcmp("png",$ext)) $src_img=imagecreatefrompng($img_name);

//gets the dimmensions of the image $old_x=imageSX($src_img); $old_y=imageSY($src_img);

// next we will calculate the new dimmensions for the thumbnail image // the next steps will be taken: // 1. calculate the ratio by dividing the old dimmensions with the new ones // 2. if the ratio for the width is higher, the width will remain the one define in WIDTH variable // and the height will be calculated so the image ratio will not change // 3. otherwise we will use the height ratio for the image // as a result, only one of the dimmensions will be from the fixed ones $ratio1=$old_x/$new_w; $ratio2=$old_y/$new_h; if($ratio1>$ratio2) { $thumb_w=$new_w; $thumb_h=$old_y/$ratio1; } else { $thumb_h=$new_h; $thumb_w=$old_x/$ratio2; }

// we create a new image with the new dimmensions $dst_img=ImageCreateTrueColor($thumb_w,$thumb_h);

// resize the big image to the new created one imagecopyresampled($dst_img,$src_img,0,0,0,0,$thumb_w,$thumb_h,$old_x,$old_y);

// output the created image to the file. Now we will have the thumbnail into the file named by $filename if(!strcmp("png",$ext)) imagepng($dst_img,$filename); else imagejpeg($dst_img,$filename);

//destroys source and destination images. imagedestroy($dst_img); imagedestroy($src_img); }

// This function reads the extension of the file. // It is used to determine if the file is an image by checking the extension. function getExtension($str) { $i = strrpos($str,"."); if (!$i) { return ""; } $l = strlen($str) - $i; $ext = substr($str,$i+1,$l); return $ext; }

// This variable is used as a flag. The value is initialized with 0 (meaning no error found) and it will be changed to 1 if an errro occures. If the error occures the file will not be uploaded. $errors=0; // checks if the form has been submitted if(isset($_POST['Submit'])) { //reads the name of the file the user submitted for uploading $image=$_FILES['image']['name']; // if it is not empty if ($image) { // get the original name of the file from the clients machine $filename = stripslashes($_FILES['image']['name']);

// get the extension of the file in a lower case format $extension = getExtension($filename); $extension = strtolower($extension); // if it is not a known extension, we will suppose it is an error, print an error message and will not upload the file, otherwise we continue if (($extension != "jpg") && ($extension != "jpeg") && ($extension != "png")) {

echo '

Unknown extension!

';

$errors=1; } else { // get the size of the image in bytes // $_FILES[\'image\'][\'tmp_name\'] is the temporary filename of the file in which the uploaded file was stored on the server $size=getimagesize($_FILES['image']['tmp_name']); $sizekb=filesize($_FILES['image']['tmp_name']);

//compare the size with the maxim size we defined and print error if bigger if ($sizekb > MAX_SIZE*1024) {

echo '

You have exceeded the size limit!

';

$errors=1; }

//we will give an unique name, for example the time in unix time format $image_name=time().'.'.$extension; //the new name will be containing the full path where will be stored (images folder) $newname="images/".$image_name; $copied = copy($_FILES['image']['tmp_name'], $newname); //we verify if the image has been uploaded, and print error instead if (!$copied) {

echo '

Copy unsuccessfull!

';

$errors=1; } else { // the new thumbnail image will be placed in images/thumbs/ folder $thumb_name='images/thumbs/thumb_'.$image_name; // call the function that will create the thumbnail. The function will get as parameters the image name, the thumbnail name and the width and height desired for the thumbnail $thumb=make_thumb($newname,$thumb_name,WIDTH,HEIGHT); }} }}

//If no errors registred, print the success message and show the thumbnail image created if(isset($_POST['Submit']) && !$errors) {

echo "

Thumbnail created Successfully!

";

echo '<img src="'.$thumb_name.'">'; }

?>

<form name="newad" method="post" enctype="multipart/form-data" action="">

<input type="file" name="image" >

<input name="Submit" type="submit" value="Upload image">

</form>

End of script...