While using images in a web application, developers can’t always include images of a particular measurement. In such cases, resizing the images for the application would be a good option but, not efficient either. For example, resizing a long vertical image into a horizontal dimension would just squeeze the image; thereby, affecting the aesthetics of the website and also reducing the purpose of it. Hence it would be smart to implement a cropping tool like ‘ImageMagick’ in order to fit images of various dimensions into a specified size.
ImageMagick is a collection of robust and convenient tools for manipulating images. It can be used to crop images of numerous formats such as JPEG, PNG, GIF, TIFF, PhotoCD and many more. ImageMagick facilitates creation of dynamic images that are fitting to the specific requirements of web applications.
Difference Between Cropping in GD Library and ImageMagic:
GD is the most commonly used extension for PHP. It is popular because it is easier to install and configure (`yum install php-gd` on Fedora, CentOS etc or `sudo apt-get php5-gd` on ubuntu). However, it has some limitations such as:
- It is comparatively slower
- It is more memory intensive
- For certain aspects it can be more complex to use.
Below I have mentioned a sample code for image cropping using GD:
[sourcecode]<?php
function resize_my_image($file, $w, $h, $crop=FALSE) {
list($width, $height) = getimagesize($file);
$r = $width / $height;
if ($crop) {
if ($width > $height) {
$width = ceil($width-($width*($r-$w/$h)));
} else {
$height = ceil($height-($height*($r-$w/$h)));
}
$newGDwidth = $w;
$newGDheight = $h;
} else {
if ($w/$h > $r) {
$newGDwidth = $h*$r;
$newGDheight = $h;
} else {
$newGDheight = $w/$r;
$newGDwidth = $w;
}
}
$src = imagecreatefromjpeg($file);
$dst = imagecreatetruecolor($newGDwidth, $newGDheight);
imagecopyresampled($dst, $src, 0, 0, 0, 0, $newGDwidth, $newGDheight, $width, $height);
return $dst;
}
$img = resize_my_image(‘/path/to/some/image.jpg’, 150, 150);
?>[/sourcecode]
You can either output it to the browser or save it to a file using the ‘imagejpeg’ function.
Imagick:
Imagick is a less frequently used PECL extension. ImageMagick is a free tool that is used for creating and manipulating images that supports over 100 different image formats. This can be used on a command line tool for any programming language. The Imagick extension essentially provides an API for all of the functionalities available in the `convert` command line tool.
Some of its advantages are:
- It is faster
- It uses less memory
- Offers more powerful functionality
- ‘Imagick’ is lot easier to use (once you figure out how), your code may end up smaller and cleaner.
The down side of using this extension is that the documentation is extremely limited and there are almost no examples available on the web. Installation on the other hand can be a painful task as well.
Although it should just be a matter of running the command `pecl install imagick`.
Sample code:
Cropping larger images:
Put a big picture named andolasoft_logo.jpg along side with your php page, run the test and check the directory to see andolasoft_logo_thumb.jpg.
Requirement:
imagemagick with imagick extension
[sourcecode]<?php
$obj = new imagick(‘andolasoft_logo.jpg’);
//resize the above image
$obj->thumbnailImage(160, 0);
//write the thumb
$obj->writeImage(‘andolasoft_logo_thumb.jpg’);
?>[/sourcecode]
To Crop Animated Image:
[sourcecode]<?php
$image = new imagick(“andolasoft_animated_logo.gif”);
$image = $image->coalesceImages(); // the trick! To crop animated image
foreach ($image as $frame) {
$frame->cropImage($width, $height, $x, $y);
$frame->setImagePage(0, 0, 0, 0); // Remove gif canvas
}
?>[/sourcecode]
$x → The X coordinate of the cropped region’s top left corner
$y → The Y coordinate of the cropped region’s top left corner
Implementing ‘ImageMagick’ would make the website look clean and flawless. Images on the other hand retain its look and feel, thereby making the application look professional and optimized.
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