Facebook API: Generating a Large Square Profile Image

facebook_image_crop.php

<?php

function generate_ticket( $src, $l, $t, $r, $b ) {

    // check to see if Image Functions Exist
    if ( !function_exists ( "imagecreate" ) || !function_exists ( "imagecreatetruecolor" ) ) {
        die( "No image create functions!" );
    }

    // get size of file
    $size = @getimagesize( $src );

    // calculate the cropped region - FB returns percentages instead of coordinates
    $l_crop = $size[0] * $l;
    $t_crop = $size[1] * $t;
    $r_crop = $size[0] * $r;
    $b_crop = $size[1] * $b;

    // find the size of the cropped image
    $newx = round( $r_crop - $l_crop, 4 );
    $newy = round( $b_crop - $t_crop, 4 );

    // fix errors in sizes - sometimes the crop isn't perfectly square
    if ( $newx != $newy ) $newx = $newy = min( $newx, $newy );

    // create the new image with the crop dimensions
    $destimg = imagecreatetruecolor( $newx, $newy ) or die ();
    // make a copy of the original image - Facbook uses JPEG
    $sourceimg = imagecreatefromjpeg( $src );

    // copy the Facebook image to the blank image, but using the cropped values instead
    @imagecopyresampled ( $destimg, $sourceimg, 0, 0, $l_crop, $t_crop, $newx, $newy, $newx, $newy ) or die ( "Cannot use GD2 here! (Error 003)" );

    // output the image to the screen
    header( "content-type: image/png" );
    imagepng( $destimg );

    // clear memory
    imagedestroy( $destimg );
    imagedestroy( $sourceimg );

}

// check if we have a valid ID
if ( isset( $_GET['id'] ) && is_numeric( $_GET['id'] ) ) {
    // get image data from Graph API using FQL
    $data = file_get_contents( 'http://graph.facebook.com/fql?q=' . urlencode( 'select pic_crop from profile where id = ' . $_GET['id'] ) );
    // fix the data
    $data = json_decode( $data );
    $pic = $data->data[0]->pic_crop;
    // call the crop function
    generate_ticket( $pic->uri, $pic->left, $pic->top, $pic->right, $pic->bottom );
}