GD Graphics Library

The GD Library, short GD or GDlib and GD2, was developed by Thomas Boutell and other open source software library for dynamic creation and manipulation of graphics. The GD library is written in C, but there are interfaces to other programming languages ​​such as Perl or PHP.

Development

The abbreviation DG stood initially for "gif draw", the original output format. As Unisys demanded for the LZW algorithm from 1999 used in the Graphics Interchange Format (GIF) for non - commercial software projects royalties (see GIF and LZW patents), the GIF output was no longer supported and instead uses the PNG format ( reading GIF files but was still possible). When the patent expired in 2004, the world was introduced the GIF support full again with version 2.0.28.

Functions

In addition to GIF and JPG and PNG WBMP files can be written. Starting with version 2.0 also TrueColor images can be generated in advance only 256 color images were possible.

Capabilities include drawing lines, rectangles, polygons, arcs, ellipses, text output with built-in, TrueType or PostScript fonts. In addition, images or excerpts can be read and manipulated by images from files. Alpha channels with 7-bit are supported. Also to create animated GIF files is possible.

A common application is the dynamic generation of Web graphics with PHP, for example, diagrams, or the generation of preview images. A number of libraries is based on GD and provides advanced features for information about graphics so JpGraph.

GD2

GD2 is the improved version of GD and today still widely used standard; For example, it is installed in PHP 5. . . GD2 With a variety of tasks to saved gif or png images may be made, for example:

  • Change the image size, the production of "stamps" ( thumbnails )
  • Color change (eg for frame graphic elements ).

List of supported programming languages

  • C / C
  • PHP
  • Perl
  • Python
  • Free Pascal
  • Objective CAML
  • REXX

Similar software packages

  • ImageMagick
  • Netpbm
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