Hello coders,

This is a PHP Class that crops images (rectangles) to squares using the GD library. First, make sure you have this extension enabled. This can be verified using the following code:

check_gd.php

<?php
if (!extension_loaded('gd')) {
    if (!dl('gd.so')) {
        exit("The GD extension is not loaded.");
    }
}
?>

The class checks if the image is already a square. If it is, it will output a message to the user. If it’s not it will calculate the necessary coordinates and crop it: to left, center or right (default is ‘center’).

crop.image.to.square.class.php

<?php
/*
--------------------------------------------------------------------------------------------
Credits: Bit Repository 

Source URL: http://www.bitrepository.com/web-programming/php/crop-rectangle-to-square.html
--------------------------------------------------------------------------------------------
*/ 

/* Crop Image Class */

class Crop_Image_To_Square {

var $source_image;
var $new_image_name;
var $save_to_folder;

function crop($location = 'center')
{
$info = GetImageSize($this->source_image);

$width = $info[0];
$height = $info[1];
$mime = $info['mime'];

if($width == $height)
{
echo 'The source image is already a square.';
}
else
{
// What sort of image?

$type = substr(strrchr($mime, '/'), 1);

switch ($type)
{
case 'jpeg':
    $image_create_func = 'ImageCreateFromJPEG';
    $image_save_func = 'ImageJPEG';
	$new_image_ext = 'jpg';
    break;

case 'png':
    $image_create_func = 'ImageCreateFromPNG';
    $image_save_func = 'ImagePNG';
	$new_image_ext = 'png';
    break;

case 'bmp':
    $image_create_func = 'ImageCreateFromBMP';
    $image_save_func = 'ImageBMP';
	$new_image_ext = 'bmp';
    break;

case 'gif':
    $image_create_func = 'ImageCreateFromGIF';
    $image_save_func = 'ImageGIF';
	$new_image_ext = 'gif';
    break;

case 'vnd.wap.wbmp':
    $image_create_func = 'ImageCreateFromWBMP';
    $image_save_func = 'ImageWBMP';
	$new_image_ext = 'bmp';
    break;

case 'xbm':
    $image_create_func = 'ImageCreateFromXBM';
    $image_save_func = 'ImageXBM';
	$new_image_ext = 'xbm';
    break;

default:
	$image_create_func = 'ImageCreateFromJPEG';
    $image_save_func = 'ImageJPEG';
	$new_image_ext = 'jpg';
}

// Coordinates calculator

   if($width > $height) // Horizontal Rectangle?
   {
	   if($location == 'center')
       {
       $x_pos = ($width - $height) / 2;
       $x_pos = ceil($x_pos);

       $y_pos = 0;
	   }
	   else if($location == 'left')
	   {
	   $x_pos = 0;
	   $y_pos = 0;
	   }
	   else if($location == 'right')
	   {
	   $x_pos = ($width - $height);
	   $y_pos = 0;
	   }

       $new_width = $height;
       $new_height = $height;
   }
   else if($height > $width) // Vertical Rectangle?
   {
	   if($location == 'center')
       {
       $x_pos = 0;

       $y_pos = ($height - $width) / 2;
       $y_pos = ceil($y_pos);
       }
	   else if($location == 'left')
	   {
	   $x_pos = 0;
	   $y_pos = 0;
	   }
	   else if($location == 'right')
	   {
	   $x_pos = 0;
	   $y_pos = ($height - $width);
	   }

       $new_width = $width;
       $new_height = $width;

   }

$image = $image_create_func($this->source_image);

$new_image = ImageCreateTrueColor($new_width, $new_height);

// Crop to Square using the given dimensions
ImageCopy($new_image, $image, 0, 0, $x_pos, $y_pos, $width, $height);

if($this->save_to_folder)
		{
	       if($this->new_image_name)
	       {
	       $new_name = $this->new_image_name.'.'.$new_image_ext;
	       }
	       else
	       {
	       $new_name = $this->new_image_name( basename($this->source_image) ).'_square_'.$location.'.'.$new_image_ext;
	       }

		$save_path = $this->save_to_folder.$new_name;
		}
		else
		{
		/* Show the image (on the fly) without saving it to a folder */
		   header("Content-Type: ".$mime);

	       $image_save_func($new_image);

		   $save_path = '';
		}

// Save image 

$process = $image_save_func($new_image, $save_path) or die("There was a problem in saving the new file.");

return array('result' => $process, 'new_file_path' => $save_path);
}
}

function new_image_name($filename)
	{
	$string = trim($filename);
	$string = strtolower($string);
	$string = trim(ereg_replace("[^ A-Za-z0-9_]", " ", $string));
	$string = ereg_replace("[ \t\n\r]+", "_", $string);

	$string = str_replace(" ", '_', $string);
	$string = ereg_replace("[ _]+", "_", $string);

	return $string;
	}
}
?>

This is an usage example of this class:

example.php

<?php
include 'crop.image.to.square.class.php';

$crop = new Crop_Image_To_Square;
$crop->source_image = 'my_rectangle_image.jpg';

$crop->save_to_folder = 'square_images/';

/* left, center or right; If none is set, center will be used as default */
$process = $crop->crop('right');

if($process['result'])
{
echo 'The rectangle image ('.$process['new_file_path'].') was cropped.';
}
?>

If you’re interested in resizing an image (i.e. to square) consider checking our post regarding images resizing.

Do you wish to receive the latest updates as soon as they are posted? Get our RSS Feed or Subscribe to the Newsletter!