LVII. Image FunctionsВведениеPHP is not limited to creating just HTML output. It can also be used to create and manipulate image files in a variety of different image formats, including gif, png, jpg, wbmp, and xpm. Even more convenient, PHP can output image streams directly to a browser. You will need to compile PHP with the GD library of image functions for this to work. GD and PHP may also require other libraries, depending on which image formats you want to work with. You can use the image functions in PHP to get the size of JPEG, GIF, PNG, SWF, TIFF and JPEG2000 images.
ТребованияIf you have the GD library (available at http://www.boutell.com/gd/) you will also be able to create and manipulate images. The format of images you are able to manipulate depend on the version of GD you install, and any other libraries GD might need to access those image formats. Versions of GD older than gd-1.6 support GIF format images, and do not support PNG, where versions greater than gd-1.6 and less than gd-2.0.28 support PNG, not GIF. GIF support was re-enabled in gd-2.0.28.
You may wish to enhance GD to handle more image formats. Таблица 1. Supported image formats
You may wish to enhance GD to deal with different fonts. The following font libraries are supported: Таблица 2. Supported font libraries
If you have PHP compiled with --enable-exif you are able to work with information stored in headers of JPEG and TIFF images. This way you can read meta data generated by digital cameras as mentioned above. These functions do not require the GD library. УстановкаTo enable GD-support configure PHP --with-gd[=DIR], where DIR is the GD base install directory. To use the recommended bundled version of the GD library (which was first bundled in PHP 4.3.0), use the configure option --with-gd. GD library requires libpng and libjpeg to compile. In Windows, you'll include the GD2 DLL php_gd2.dll as an extension in php.ini. The GD1 DLL php_gd.dll was removed in PHP 4.3.2. Also note that the preferred truecolor image functions, such as imagecreatetruecolor(), require GD2.
To disable GD support in PHP 3 add --without-gd to your configure line. Enhance the capabilities of GD to handle more image formats by specifying the --with-XXXX configure switch to your PHP configure line. Таблица 3. Supported image formats
Enhance the capabilities of GD to deal with different fonts by specifying the --with-XXXX configure switch to your PHP configure line. Таблица 4. Supported font libraries
Настройка во время выполненияThere are no image specific configurations but you may be interested in the exif extension directives. Типы ресурсовДанное расширение не определяет никакие типы ресурсов. Предопределенные константыПеречисленные ниже константы определены данным расширением и могут быть доступны только в том случае, если PHP был собран с поддержкой этого расширения или же в том случае, если данное расширение подгружается во время выполнения.
Примеры
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