PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

484 Chapter 22 Generating Images
Setting Up Image Support in PHP
Some of the image functions in PHP are always available, but most of them require the
GD2 library. Detailed information about GD2 is available at http://www.libgd.org/
Main_Page.
Since PHP 4.3, PHP comes with its own forked version of the GD2 library,
supported by the PHP team.This version is easier to install with PHP and is usually
more stable, so it’s advisable to use this version. Under Windows, PNGs and JPEGs are
automatically supported as long as you have the php_gd2.dll extension registered.You
can do this by copying the php_gd2.dll file from your PHP installation directory (in the
\ext subfolder) to your system directory (the C:\Windows\system directory if using
Windows XP).You must also uncomment the following line in your php.ini file by
removing the “;” at the beginning of the line:
extension=php_gd2.dll
If you have Unix and want to work with PNGs, you need to install libpng from
http://www.libpng.org/pub/png/ and zlib from http://www.gzip.org/zlib/.
You then need to configure PHP with the following options:
--with-png-dir=/path/to/libpng
--with-zlib-dir=/path/to/zlib
If you have Unix and want to work with JPEGs, you need to download jpeg-6b and
recompile GD with JPEG support included.You can download it from ftp://ftp.uu.net/
graphics/jpeg/.
You then need to reconfigure PHP with the following option and recompile it:
--with-jpeg-dir=/path/to/jpeg-6b
If you want to use TrueType fonts in your images, you also need the FreeType library. It
also comes with PHP since version 4. Alternatively, you can download it from
http://www.freetype.org/.
If you want to use PostScript Type 1 fonts instead, you need to download t1lib,
available from ftp://sunsite.unc.edu/pub/Linux/libs/graphics/.
You then need to run PHP’s configure program with
--with-t1lib[=path/to/t1lib]
Finally, you will, of course, need to configure PHP using --with-gd.
Understanding Image Formats
The GD library supports JPEG, PNG, and WBMP formats. It no longer supports the
GIF format. Let’s briefly look at each of these formats.