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Image resize script

Hi there,

I'm looking to resize an image dynamically with PHP. I've looked at ImageMagik however I don't want to install this on every server I work on. I'm looking for a different way. Do you know of one? I'm hoping to create a thumb using PHP's available image functions however I"m not very well practiced at using them. Also is the quality of the photo ruined? Any code would be greatly appreciated or tips. Thanks!

//define a maxim size for the uploaded imagesdefine ("MAX_SIZE","1000");

// define the width and height for the thumbnaildefine ("WIDTH","100");define ("HEIGHT","74");

// 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 imagefunction 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 libraryif(!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 oneimagecopyresampled($dst_img,$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 $filenameif(!strcmp("png",$ext))imagepng($dst_img,$filename); elseimagejpeg($dst_img,$filename);

// 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 submittedif(isset($_POST['submit'])) {//reads the name of the file the user submitted for uploading$picture=$_FILES['picture']['name'];

// if it is not empty

//FOTO 1if ($picture) {// get the original name of the file from the clients machine$filename = stripslashes($_FILES['picture']['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 continueif (($extension != "jpg") && ($extension != "jpeg") && ($extension != "png")) { echo '<h1>Format of the picture is not allowed</h1>';$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($_FILES['picture']['tmp_name']);$sizekb=filesize($_FILES['picture']['tmp_name']);

//compare the size with the maxim size we defined and print error if biggerif ($sizekb1 > MAX_SIZE*1024) {echo '<h1>Picture is too big</h1>'; $errors=1;}

//we verify if the image has been uploaded, and print error insteadif (!$copied) {echo '<h1>Copy failed!</h1>'; $errors=1;} else {// the new thumbnail image will be placed in images/thumbs/ folder$thumb_name ='images/thumbs/'.$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); } // else verify upload}// else check extension} //Check ifi file empty