GD Graphics Library

GD Graphics Library

Developer(s)	Thomas Boutell
Stable release	2.0.35 / November 28, 2007
Repository	bitbucket.org/libgd/gd-libgd
Written in	C
Operating system	Cross-platform
Type	Graphical Library
License	BSD-like license
Website	LibGD

The GD Graphics Library is a graphics software library by Thomas Boutell and others for dynamically manipulating images. Its native programming language is ANSI C, but it has interfaces for many other programming languages. It can create GIFs, JPEGs, PNGs, and WBMPs. Support for drawing GIFs was dropped in 1999 when Unisys revoked the royalty-free license granted to non-commercial software projects for the LZW compression method used by GIFs. When the Unisys patent expired worldwide on July 7, 2004, GIF support was subsequently re-enabled.

GD originally stood for "GIF Draw". However, since the revoking of the Unisys license, it has informally stood for "Graphics Draw".

GD can create images composed of lines, arcs, text (using program-selected fonts), other images, and multiple colors. Version 2.0 adds support for truecolor images, alpha channels, resampling (for smooth resizing of truecolor images), and many other features.

GD supports numerous programming languages including C, PHP, Perl, Python, OCaml, Tcl, Lua, Pascal, GNU Octave, REXX, and Ruby. In addition, the "Fly" command line interpreter allows for image creation ("on the fly") using GD. GD scripts can be thus be written in potentially any language and run using this tool.

GD is extensively used with PHP, where a modified version supporting additional features is included by default as of PHP 4.3 and was an option before that. As of PHP 5.3, a system version of GD may be used as well, to get the additional features that were previously available only to the bundled version of gd.

Change in development

On January 4, 2007, the project was handed over to and is now headed by Pierre Joye, a well-known PHP developer. The new developer then released several versions, but there have been no releases since 2007.

Example

This is an example from the PHP GD documentation on the imagefilledarc() function

<?php

// create image
$image = imagecreatetruecolor(100, 100);

// allocate some colors
$white    = imagecolorallocate($image, 0xFF, 0xFF, 0xFF);
$gray     = imagecolorallocate($image, 0xC0, 0xC0, 0xC0);
$darkgray = imagecolorallocate($image, 0x90, 0x90, 0x90);
$navy     = imagecolorallocate($image, 0x00, 0x00, 0x80);
$darknavy = imagecolorallocate($image, 0x00, 0x00, 0x50);
$red      = imagecolorallocate($image, 0xFF, 0x00, 0x00);
$darkred  = imagecolorallocate($image, 0x90, 0x00, 0x00);

// make the 3D effect
for ($i = 60; $i > 50; $i--) {
   imagefilledarc($image, 50, $i, 100, 50, 0, 45, $darknavy, IMG_ARC_PIE);
   imagefilledarc($image, 50, $i, 100, 50, 45, 75 , $darkgray, IMG_ARC_PIE);
   imagefilledarc($image, 50, $i, 100, 50, 75, 360 , $darkred, IMG_ARC_PIE);
}

imagefilledarc($image, 50, 50, 100, 50, 0, 45, $navy, IMG_ARC_PIE);
imagefilledarc($image, 50, 50, 100, 50, 45, 75 , $gray, IMG_ARC_PIE);
imagefilledarc($image, 50, 50, 100, 50, 75, 360 , $red, IMG_ARC_PIE);

// flush image
header('Content-type: image/png');
imagepng($image);
imagedestroy($image);
?>

Which outputs a 3D looking pie chart

See also

• GraphicsMagick
• ImageMagick
• Netpbm

External links

• PHP GD Bar Chart
• GD Graphics Library (Current development site)
• GD Graphics Library (Old development site)
• Image Functions (PHP), support in PHP