GD Thumbnail Class

Apr

Hi all, this little set of functions will create thumbnails of images using PHP’s built in GD functionality.

The first function will create thumbnails that save the original aspect ratio. The second will create a sqaure cropped thumbnail.

To learn more about GD, and to make sure you have it installed on your webserver (Most hosts do this as standard), click here.

You can download the original as a zip here: [gd_resize.zip 0.6kb]

Here is the source code:


<?php



function resize_normal($image_type,$file_old,$file_new,$max_size)

{

    //

    // $image_type should be either:


    //

    // png, jpg or gif

    //

    list($width, $height) = getimagesize($file_old);


    if($width <= $max_size && $height <= $max_size){

        copy($file_old, $file_new);

    } else {


        if ($width > $height){

            $resize_percent = $max_size / $width;

            $new_height = $height * $resize_percent;


            $new_width = $max_size;

        } else {

            $resize_percent = $max_size / $height;

            $new_height = $max_size;


            $new_width = $width * $resize_percent;

        }

        $temp_image = imagecreatetruecolor($new_width, $new_height);

        switch($image_type){


            case 'png':

                $image = imagecreatefrompng($file_old);

                imagecopyresampled($temp_image, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);


                imagepng($temp_image, $file_new);

                break;

            case 'jpg':

                $image = imagecreatefromjpeg($file_old);

                imagecopyresampled($temp_image, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);


                imagejpeg($temp_image, $file_new);

                break;

            case 'gif':

                $image = imagecreatefromgif($file_old);

                imagecopyresampled($temp_image, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);


                imagegif($temp_image, $file_new);

                break;

        }

    }

}



function resize_square($image_type,$file_old,$file_new,$max_size)


{

    //

    // $image_type should be either:

    //

    // png, jpg or gif

    //

    list($width, $height) = getimagesize($file_old);


    if($width <= $max_size && $height <= $max_size){

        copy($file_old, $file_new);

    } else {


        if ($width > $height) {

            $src_w = $src_h = $height;

            $src_y = 0;

            $src_x = round(($width - $height) / 2);


        } else {

            $src_w = $src_h = $width;

            $src_x = 0;

            $src_y = round(($height - $width) / 2);


        }

        $temp_image = imagecreatetruecolor($max_size, $max_size);

        switch($image_type){

            case 'png':

                $image = imagecreatefrompng($file_old);


                imagecopyresampled($temp_image, $image, 0, 0, $src_x, $src_y, $max_size, $max_size, $src_w, $src_h);


                imagepng($temp_image, $file_new);

                break;

            case 'jpg':

                $image = imagecreatefromjpeg($file_old);

                imagecopyresampled($temp_image, $image, 0, 0, $src_x, $src_y, $max_size, $max_size, $src_w, $src_h);


                imagejpeg($temp_image, $file_new);

                break;

            case 'gif':

                $image = imagecreatefromgif($file_old);

                imagecopyresampled($temp_image, $image, 0, 0, $src_x, $src_y, $max_size, $max_size, $src_w, $src_h);


                imagegif($temp_image, $file_new);

                break;

        }

    }

}



?>

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