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pradeep

3Sep2005 11:56

Creating image thumbnails with PHP!

If we intend to make an image gallery, and we would like to show the thumbails of the images, it wouldn't be a wise idea to show the original images with their height & width modified in the <img> tag, that would result in low image quality & higher download time. The solution to this problem would be creating thumbnails at the server end and display them instead.
This solution can be approached in two ways, you can create the thumbnails once and for all or create thumbnails everytime at runtime.
For this purpose, I wrote a class which will create the thumbnail.

The class:

PHP Code:


		
			
/* 
 *    File        :    thumb.class.php
 *    Description    :    Class for creating thumbnails
 */
 
 class Thumb
 {
     var $filename;
     var $img;
     var $height;
     var $width;
     var $ratio = 10;
     var $oldim;
     var $oldh;
     var $oldw;
 
 
     function filename($file) /* used for setting filename */
     {
         $this->filename = $file;
     }
 
     function setRatio($ratio) /* used for setting ratio */
     {
         $this->ratio = $ratio;
     }
 
     function init() /* creates the GD stream */
     {
         $this->img = imagecreatetruecolor($this->width,$this->height);
     }
 
     function calculateSize() /* to calculate the output size */
     {
         //$this->info = getimagesize($this->filename); /* returns height,width,type,attribute */
         $this->oldim = imagecreatefromjpeg($this->filename);
         $this->oldw = imagesx($this->oldim);
         $this->oldh = imagesy($this->oldim);
 
         /* code to re-calculate size maintaining the aspect ratio */
         $this->width = ($this->oldw/100)*$this->ratio;
         $this->height = ($this->oldh/100)*$this->ratio;
 
         $this->init();
         return true;
     }
 
     function finish()
     {
         $this->calculateSize();
 imagecopyresampled($this->img,$this->oldim,0,0,0,0,$this->width,$this->height,$this->oldw,$this->oldh);
         header("Content-Type: image/jpeg");
         imagejpeg($this->img);
     }
 }

An example:

PHP Code:


		
			
<?
 require_once("thumb.class.php");
 
 $im = new Thumb;
 $im->filename("abhishek.jpg");
 $im->setRatio(10);
 $im->finish();
 
 ?>

Hope, everyone likes this, you have any suggestions please let me know.

rekha

8Sep2010 17:50

Re: Creating image thumbnails with PHP!

Hi,

Your articles are really nice.

I want to create thumbnails from a swf file.How can I do it.I tried FFMPEG but it is not working for swf files.

Any help will be appreciated.

jaksonx

22Sep2010 16:57

Re: online PHP scripts!

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Thanks!

Max2010

14Oct2010 14:23

Re: Creating image thumbnails with PHP!

I used GD libraries too, now I'm using image magick with Imagick php libraries.
It's easy as:
...
$im = new Imagick($image_filename);
$im->resizeImage($x, $y, imagick::FILTER_LANCZOS, 1);
$im->writeImage($thumbnail_filename);
...

And it's better quality. Problem is that not any server has image magick installed.
Thanks for sharing!

shrikrishnatech

19Nov2010 11:31

Re: Creating image thumbnails with PHP!

This code is also useful

Code:

?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 '<h1>Unknown extension!</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['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 '<h1>You have exceeded the size limit!</h1>';

                $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 '<h1>Copy unsuccessfull!</h1>';

                $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 "<h1>Thumbnail created Successfully!</h1>";

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

}



 ?>

<!-- next comes the form, you must set the enctype to "multipart/form-data" and use an input type "file"  -->



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

<table>

    <tr><td><input type="file" name="image" ></td></tr>

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

</table>    

</form>

parryndsxl

19Nov2010 15:10

Re: Creating image thumbnails with PHP!

hi..

How to make the shopping cart site with free website creator..??? meet again.

shamilahamed

27Dec2010 19:33

Re: Creating image thumbnails with PHP!

hii tat was an very useful yaar!

shamilahamed

27Dec2010 19:35

Re: Creating image thumbnails with PHP!

can any one help me..
how to write an php code for checkboxs..
code for checking all and unchecking the checkbox..

kajal123

7Mar2011 13:35

Re: Creating image thumbnails with PHP!

Hi friends,,,,I think this article is very nice., you have shared really useful information with us. It has lots of worth for those people who want to start web hosting business. I'm running my own online business successfully with help of it provides me scripts to make easier to my business. I'm very thankful to that caters such kind of great services..........thanks for sharing that.........regards,,,,
kajal,,:):):)

marksteven

13Mar2011 14:23

Re: Creating image thumbnails with PHP!

This are really good coding of PHP! Thank you

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