ImageMagick and PHP: Your Best Friend Or Your Worst Nightmare (Installing and a Few Examples)

1 - Installing ImageMagick for PHP

Initially, I tried to install imagick using "pecl install imagick", but that failed with this error:

Fatal error: Allowed memory size of 8388608 bytes exhausted (tried to 
   allocate 40 bytes) in /usr/local/lib/php/PEAR.php on line 766

According to this post on ActiveState, "...the pecl command intentionally ignores php.ini to avoid locking problems when upgrading PHP."  So, even if you change the memory limit config tunable in php.ini (like I initially tried), the pecl install is still going to fail.  So, the solution to this is to use pear instead.  I successfully installed imagick with "pear install pecl/imagick-2.2.1" as root.  From what I read online, there are some known issues with PHP 5.1.6 and imagic-2.2.2 (the latest stable version as of 5/1/09).  As a result, I installed one rev behind to avoid the linkage issue.

The pear install worked fine, and I saw the following post-install output on my root console:

Build process completed successfully
Installing '/var/tmp/pear-build-mark/.../usr/lib/php/modules/imagick.so'
install ok: channel://pecl.php.net/imagick-2.2.1
You should add "extension=imagick.so" to php.ini

The install process suggests that I should add "extension=imagic.so" to php.ini.  Well, on CentOS (and probably other distros), the module loading INI's were moved to /etc/php.d.  So, I had to create my own /etc/php.d/imagick.ini file to load imagick into PHP ...

; to load imagick (ImageMagick)
extension=imagick.so

To validate the install, I wrote a simple app in PHP to test ImageMagick with the PHP engine.  This test script draws a red 200x200px square with a large circle in it (as shown below) ...

<?php

  $canvas = new Imagick();

  $draw = new ImagickDraw();
  $draw->circle(0,200,10,10);

  $canvas->newImage(200,200,"#ff0000");
  $canvas->drawImage($draw);
  $canvas->setImageFormat('png');

  header("Content-Type: image/png");
  echo $canvas;

?>

Yea!  Our ImageMagick install works with PHP; I can now build dynamic images on the fly programatically with PHP.


2 - The Problem

While building a new web-application for a client, I received a request to add a few custom headers to several columns in a table.  The headers, directly correspond to fields in a MySQL database table:



To solve this problem, I had two options.

First, I could open up Photoshop and manually create these static header images myself, one-by-one.  Unfortunately, if I took that approach, and the client needs me to add or change a column name, I would have to go back into Photoshop and manually make the change.  I would also have to upload the new/modified image file, and tweak some source code to include the new or modified table header image.

The other preferred option is to use ImageMagick!  I solved this problem by writing a small PHP script that builds a dynamic PNG-image that contains the text I want on the fly.  No Photoshop, no FTP/SCP'ing files around, etc.  If I need to add or change the header name for a column in the table, it's literally a one-line code change.


3 - My Solution

Here's the PHP code I used to create a 100x14px PNG header image in the web-app (header images shown in the screen shot above):

<?php

  $canvas = new Imagick();

  $text = $_GET['t'];
  if(empty($text)){
    $text = "ERROR";
  }

  // Sanitize the input from a GET.  Strip out any non-word
  // characters and other junk.  If it's not a word-character
  // or a space, then remove it from the string.
  $text = preg_replace("/[^\S ]/","",$text);

  // Limit the size of the string to 20-chars.
  $text = substr($text, 0, 20);

  $draw = new ImagickDraw();

  // I placed arial.ttf (TrueType Font file) in the same
  // directory of the script.  ImageMagick uses this file
  // to annotate the image with text.
  $draw->setFont("arial.ttf");
  $draw->setFontSize(10);
  $draw->annotation(0,10,$text);

  $canvas->newImage(100,14,"#E1EFF9");

  // Draw the image onto the canvas.
  $canvas->drawImage($draw);

  // Rotate the image
  $canvas->rotateImage(new ImagickPixel(),"-90");

  // I want a PNG
  $canvas->setImageFormat('png');

  header("Content-Type: image/png");
  echo $canvas;

?>

If you need it, the Arial font file I used can be downloaded here.  To use this script, save it to a place on your server that executes .php scripts.  In your code that builds a chunk of dynamic HTML (or in a static HTML file), you can call this script using the <img> tag like so:

<img src="/path/to/script/image.php?t=i+love+kolich.com" />

You can change the t=... argument to whatever you want.  In this case, here's what this <img> would look like:




Get 'er done.  Enjoy.