Kore Nordmann - PHP / Projects / Politics
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

:Author: 		Kore Nordmann
:Date:			Thu, 20 Dec 2007 17:46:24 +0100
:Revision: 		3
:Copyright:		CC by-sa


==================================
Comparision of PHP image libraries
==================================

:Description:
  A comparision of speed and output quality of PHP libraries for image
  creation.

I find this always a bit hard to phrase, because I am not only comparing
libraries here, but also formats or extensions which are just used to create
some graphic, which also may be used for something completely different (DOM).
I am talking about general ways to create graphics with PHP here.

In my article series I showed several ways on how to create images with PHP,
going into implementation details etc. Now I just want to provide a very rough
overview on speed and quality of the extensions. ::

   *                  kn::Graphic::Cairo (250): 0.0651s (0.000260)
   *                    kn::Graphic::Svg (250): 0.0973s (0.000389)
   *                  kn::Graphic::Flash (250): 0.1271s (0.000509)
   * kn::Graphic::GdWithoutSupersampling (250): 0.1926s (0.000770)
   *                     kn::Graphic::Gd (250): 0.5291s (0.002116)

.. image::  bench_cairo.png
   :width:  150px
   :height: 150px
   :alt: 	Cairo output
   :align:  right

For this microbenchmark I disabled stuff like the border size reduction, which
would cost some additional time for SVG and Flash generation, but I am not
really sure if you would always need that.

.. image::  bench_gd.png
   :width:  150px
   :height: 150px
   :alt: 	GD output
   :align:  right

You can see that Cairo is a lot faster then everything else, even with
disabled supersampling in GD. Flash and SVG are actually rendered by the
Client (the visiting browser or similar), so it is not completely fair
comparision.

.. image::  bench_gd_nos.png
   :width:  150px
   :height: 150px
   :alt: 	GD no supersampling
   :align:  right

Beside the speed there is another thing to mention about Cairo: It produces
the output with the highest quality. Yeah, it is faster then everything else,
and the created images are of the best quality. From my point of view it
should be the default for image creation with PHP - and you should use it at
least, when you are able to install a pecl extension.

Here are some references, if you want to get more detailed information:

- `Image creation with PHP`__
- `pecl/cairo_wrapper`__ by `Hartmut Holzgraefe`__
- `Supersampling with GD`__
- `Border size reduction`__

__ /blog/image_creation_with_php_formats.html
__ /blog/image_creation_with_php_formats.html#id39
__ http://www.php-groupies.de/blogs/
__ /blog/image_creation_with_php_shapes.html#id26
__ /blog/image_creation_with_php_shapes.html#id34

The benchmark code
------------------

Here is the benchmark code. It does a lot calculations on the PHP side, using
the transformation matrix to rotate the polygon, so that it should be somehow
like a usual real world application. If you remaove that, you would get an
even bigger speed gain from Cairo. ::

	<?php

	namespace kn::Graphic;

	require_once dirname( __FILE__ ) . '/../base.php';

	// Define a GD class wrapper without supersampling
	class GdWithoutSupersampling extends GD
	{
		public function __construct( $width, $height )
		{
			parent::__construct( $width, $height, 1 );
		}
	}

	$iterations = 250;
	$classes = array(
		'Cairo',
		'Svg',
		'Flash',
		'Gd',
		'GdWithoutSupersampling',
	);

	foreach ( $classes as $class )
	{
		// Store start time
		$start = microtime( true );

		// Prefix class name with local namespace
		$class = __NAMESPACE__ . '::' . $class;

		// Create graphics
		for ( $i = 0; $i < $iterations; ++$i )
		{
			$graphic = new $class( 150, 150 );
			$graphic->addBitmap(
				new Coordinate( 50, 129 ),
				'bitmap.png'
			);

			$polygon = new Polygon(
				new Coordinate( 75, 75 ), new Coordinate( 75, 10 ), new Coordinate( 85, 30 )
			);
			$transformation = Matrix::createRotationMatrixAroundPoint( -10, new Coordinate( 75, 75 ) );

			for ( $i = 0; $i < 360; $i += 10 )
			{
				$graphic->drawPolygon(
					$polygon,
					new Color( '#2e35367f' ),
					true
				);
				$graphic->drawPolygon(
					$polygon,
					new Color( '#eeeeef7f' ),
					false
				);

				$polygon->transform( $transformation );
			}

			$graphic->save( $class );

			// Free memory
			unset( $graphic, $polygon, $transformation );
		}

		// Echo used time
		printf( "% 40s (%d): %02.4fs (%1.6f)\n",
			$class,
			$iterations,
			$time = ( microtime(true) - $start ),
			$time / $iterations
		);
	}

The abstraction layer I use here is the one described in my article series on
`"Image creation with PHP"`__, without the border size reduction, as mentioned
above.

__ /blog/image_creation_with_php_formats.html

Update
------

I posted an update__ of this comparision including iMagick.

__ comparison_of_php_image_libraries_update.html



Trackbacks
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Comments
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- Alexey Zakhlestin at Wed, 12 Dec 2007 15:34:21 +0100

  What about these?

  http://magickwand.org/ http://pecl.php.net/package/imagick

- kore at Wed, 12 Dec 2007 17:33:40 +0100

  imagemagick (which is behind both mentioned extensions) is more for image
  manipulation, and not for image creation. Some of the things required in the
  described abstraction layer can't be easily implemented with them.

  So, I skipped them, because they have a different focus, and Mikko describes
  iMagick very well in his blog: http://valokuva.org/?cat=1

- BVis at Wed, 12 Dec 2007 23:58:56 +0100

  Would be very interesting include in the comparison the result with the new
  Imagick2 PHP Library... ;)

- open source cms at Thu, 13 Dec 2007 22:40:06 +0100

  @BVis: I will wait for this results :)