Podręcznik PHP
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# XLI. Image functions

# Wprowadzenie

PHP 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.

> Notatka: Read requirements section about how to expand image capabilities to read, write and modify images and to read meta data of pictures taken by digital cameras.

# Wymagania

If 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 support PNG, not GIF.

> Notatka: Since PHP 4.3 there is a bundled version of the GD lib. This bundled version has some additional features like alpha blending, and should be used in preference to the external library since it's codebase is better maintained and more stable.

You may wish to enhance GD to handle more image formats.

Tabela 1. Supported image formats

Image format | Library to download | Notes
--- | --- | ---
`gif` |  | Only supported in GD versions older than gd-1.6. Read-only GIF support is available with PHP 4.3.0 and the bundled GD-library.
`jpeg-6b` | ftp://ftp.uu.net/graphics/jpeg/ |
`png` | http://www.libpng.org/pub/png/libpng.html | Only supported in GD versions greater than gd-1.6.
`xpm` | ftp://metalab.unc.edu/pub/Linux/libs/X/!INDEX.html | It's likely you have this library already available, if your system has an installed X-Environment.

You may wish to enhance GD to deal with different fonts. The following font libraries are supported:

Tabela 2. Supported font libraries

Font library | Download | Notes
--- | --- | ---
`FreeType 1.x` | http://www.freetype.org/ |
`FreeType 2` | http://www.freetype.org/ |
`T1lib` | ftp://sunsite.unc.edu/pub/Linux/libs/graphics/) | Support for Type 1 fonts.

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 does not require the GD library.

> Notatka: PHP does not require any additional library for the exif module.

# Instalacja

To 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`. 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 enable exif support in Windows, php_mbstring.dll must be loaded prior to php_exif.dll in php.ini.

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.

Tabela 3. Supported image formats

Image Format | Configure Switch
--- | ---
`jpeg-6b` | To enable support for jpeg-6b add `--with-jpeg-dir=DIR`.
`png` | To enable support for png add `--with-png-dir=DIR`. Note, libpng requires the zlib library, therefore add `--with-zlib-dir[=DIR]` to your configure line.
`xpm` | To enable support for xpm add `--with-xpm-dir=DIR`. If configure is not able to find the required libraries, you may add the path to your X11 libraries.

Enhance the capabilities of GD to deal with different fonts by specifying the `--with-XXXX` configure switch to your PHP configure line.

Tabela 4. Supported font libraries

Font library | Configure Switch
--- | ---
`FreeType 1.x` | To enable support for FreeType 1.x add `--with-ttf[=DIR]`.
`FreeType 2` | To enable support for FreeType 2 add `--with-freetype-dir=DIR`.
`T1lib` | To enable support for T1lib (Type 1 fonts) add `--with-t1lib[=DIR]`.
`Native TrueType string function` | To enable support for native TrueType string function add `--enable-gd-native-ttf`.

# Konfiguracja startowa

Na działanie tych funcji wpływają ustawienia zawarte w pliku `php.ini`.

Exif supports automatically conversion for Unicode and JIS character encodings of user comments when module mbstring is available. This is done by first decoding the comment using the specified characterset. The result is then encoded with another characterset which should match your `HTTP` output.

Tabela 5. Exif configuration options

Name | Default | Changeable
--- | --- | ---
exif.encode_unicode | "ISO-8859-15" | PHP_INI_ALL
exif.decode_unicode_motorola | "UCS-2BE" | PHP_INI_ALL
exif.decode_unicode_intel | "UCS-2LE" | PHP_INI_ALL
exif.encode_jis | "" | PHP_INI_ALL
exif.decode_jis_motorola | "JIS" | PHP_INI_ALL
exif.decode_jis_intel | "JIS" | PHP_INI_ALL

For further details and definition of the PHP_INI_* constants see ini_set().

Oto krótkie wyjaśnienie dyrektyw konfiguracji.

`exif.encode_unicode` string

  `exif.encode_unicode` defines the characterset UNICODE user comments are handled. This defaults to ISO-8859-15 which should work for most non Asian countries. The setting can be empty or must be an encoding supported by mbstring. If it is empty the current internal encoding of mbstring is used.

`exif.decode_unicode_motorola` string

  `exif.decode_unicode_motorola` defines the image internal characterset for Unicode encoded user comments if image is in motorola byte order (big-endian). This setting cannot be empty but you can specify a list of encodings supported by mbstring. The default is UCS-2BE.

`exif.decode_unicode_intel` string

  `exif.decode_unicode_intel` defines the image internal characterset for Unicode encoded user comments if image is in intel byte order (little-endian). This setting cannot be empty but you can specify a list of encodings supported by mbstring. The default is UCS-2LE.

`exif.encode_jis` string

  `exif.encode_jis` defines the characterset JIS user comments are handled. This defaults to an empty value which forces the functions to use the current internal encoding of mbstring.

`exif.decode_jis_motorola` string

  `exif.decode_jis_motorola` defines the image internal characterset for JIS encoded user comments if image is in motorola byte order (big-endian). This setting cannot be empty but you can specify a list of encodings supported by mbstring. The default is JIS.

`exif.decode_jis_intel` string

  `exif.decode_jis_intel` defines the image internal characterset for JIS encoded user comments if image is in intel byte order (little-endian). This setting cannot be empty but you can specify a list of encodings supported by mbstring. The default is JIS.

# Typy zasobów

To rozszerzenie nie posiada żadnych rodzajów zasobów.

# Predefiniowane stałe

Poniższe stałe są zdefiniowane w tym rozszerzeniu i stają się dostępne, gdy rozszerzenie jest dokompilowane do PHP, lub załadowane dynamicznie przy starcie.

`IMG_GIF` (integer)

`IMG_JPG` (integer)

`IMG_JPEG` (integer)

`IMG_PNG` (integer)

`IMG_WBMP` (integer)

`IMG_XPM` (integer)

`IMG_COLOR_TILED` (integer)

`IMG_COLOR_STYLED` (integer)

`IMG_COLOR_BRUSHED` (integer)

`IMG_COLOR_STYLEDBRUSHED` (integer)

`IMG_COLOR_TRANSPARENT` (integer)

`IMG_ARC_ROUNDED` (integer)

`IMG_ARC_PIE` (integer)

`IMG_ARC_CHORD` (integer)

`IMG_ARC_NOFILL` (integer)

`IMG_ARC_EDGED` (integer)

`IMAGETYPE_GIF` (integer)

`IMAGETYPE_JPEG` (integer)

`IMAGETYPE_PNG` (integer)

`IMAGETYPE_SWF` (integer)

`IMAGETYPE_PSD` (integer)

`IMAGETYPE_BMP` (integer)

`IMAGETYPE_WBMP` (integer)

`IMAGETYPE_XBM` (integer)

`IMAGETYPE_TIFF_II` (integer)

`IMAGETYPE_TIFF_MM` (integer)

`IMAGETYPE_IFF` (integer)

`IMAGETYPE_JB2` (integer)

`IMAGETYPE_JPC` (integer)

`IMAGETYPE_JP2` (integer)

`IMAGETYPE_JPX` (integer)

`IMAGETYPE_SWC` (integer)

# Przykłady

Przykład 1. PNG creation with PHP
`<?php header("Content-type: image/png"); $string = $_GET['text']; $im = imagecreatefrompng("images/button1.png"); $orange = imagecolorallocate($im, 220, 210, 60); $px = (imagesx($im) - 7.5 * strlen($string)) / 2; imagestring($im, 3, $px, 9, $string, $orange); imagepng($im); imagedestroy($im); ?>`

This example would be called from a page with a tag like: <img src="button.php?text=text">. The above button.php script then takes this "text" string and overlays it on top of a base image which in this case is "images/button1.png" and outputs the resulting image. This is a very convenient way to avoid having to draw new button images every time you want to change the text of a button. With this method they are dynamically generated.

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ob_iconv_handler | Początek rozdziału | exif_imagetype