Specifications

Advanced PHP Techniques

ART IV

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One of the useful things you can do with PHP is create images on-the-fly. PHP has some built-

in image information functions, and you can also use the GD library to create new images or

manipulate existing ones. This chapter discusses how to use the image functions to achieve

some interesting and useful effects.

We will look at

• Setting up image support in PHP

• Understanding image formats

• Creating images

• Using text and fonts to create images

• Drawing figures and graphing data

Specifically, we’ll look at two examples: generating Web site buttons on-the-fly, and drawing a

bar chart using figures from a MySQL database.

Setting Up Image Support in PHP

Image support in PHP is available via the gd library, available from

http://www.boutell.com/gd/

Version 1.6.2 comes bundled with PHP 4. By default, the PNG format is supported. If you also

want to work with JPEGs, you will need to download jpeg-6b, and recompile gd with jpeg sup-

port included. You can download this from

ftp://ftp.uu.net/graphics/jpeg/

You will then need to reconfigure PHP with the

--with-jpeg-dir=/path/to/jpeg-6b

option, and recompile it.

If you want to use TrueType fonts in your images, you will also need the FreeType library.

This also comes with PHP 4. Alternatively, you can download this from

http://www.freetype.org/

If you want to use PostScript Type 1 fonts instead, you will need to download t1lib,

available from

ftp://ftp.neuroinformatik.ruhr-uni-bochum.de/pub/software/t1lib/

You will then need to run PHP’s configure program with

--with-t1lib[=path/to/t1lib]

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