Datei: /php/Graphics.php, Stand: 03.03.2001, 18:36
<?php
// +----------------------------------------------------------------------+
// | PHP version 4.0 |
// +----------------------------------------------------------------------+
// | Copyright (c) 1997, 1998, 1999, 2000, 2001 The PHP Group |
// +----------------------------------------------------------------------+
// | This source file is subject to version 2.0 of the PHP license, |
// | that is bundled with this package in the file LICENSE, and is |
// | available at through the world-wide-web at |
// | http://www.php.net/license/2_02.txt. |
// | If you did not receive a copy of the PHP license and are unable to |
// | obtain it through the world-wide-web, please send a note to |
// | license@php.net so we can mail you a copy immediately. |
// +----------------------------------------------------------------------+
// | Authors: Ulf Wendel <ulf.wendel@phpdoc.de> |
// +----------------------------------------------------------------------+
//
// $Id: Graphics.php,v 1.3 2001/03/02 16:16:00 sbergmann Exp $
require_once 'Cache.php';
/**
* Graphics disk cache.
*
* The usual way to create images is to pass some arguments that describe the image
* to a script that dynamically creates an image. For every image of a page
* a new PHP interpreter gets started. This is a good way to kill your webserver.
*
* When dealing with dynamically generated images you should not call another script
* to generate the images but generate the images by the script that produces the page
* that contains the images. This is a major improvement but it's only half the way.
*
* There's no need to rerender an image on every request. A simple disk cache can reduce
* the computation time dramatically. This is what the class graphics_cache is for.
*
* Usage:
*
* // create an instance of the graphics cache
* $cache = new graphics_cache;
*
* $img = ImageCreate(...);
*
* // compute an ID for your image based on typical parameters
* $id = m5d( $size, $colors, $label);
*
* // check if it's cached
* if (!($link = $cache->getImageLink($id, "gif"))) {
*
* // hmmm, it's not cached, create it
* ...
* // cacheImageLink() and cacheImage() make the ImageGIF() call!
* // cacheImage() returns the value of ImageGIF() [etc.], cacheImageLink() returns a URL
* $link = $cache->cacheImageLink($id, $img, "gif");
*
* }
*
* // Ok, let's build the ImageLink
* $size = getImageSize($link[0]);
* printf('<img src="%s" %s>', $link[1], $size[3]);
*
* // for cacheImage():
* // header("Content-type: image/gif"); print $cache->cacheImage($id, $img, "gif");
*
*
* The class requires PHP 4.0.2+ [ImageType()]. Note that cacheImage() works with
* the output buffer. Modify it if required!
*
* @author Ulf Wendel <ulf.wendel@phpdoc.de>
* @version $Id: Graphics.php,v 1.3 2001/03/02 16:16:00 sbergmann Exp $
* @package Cache
*/
class Cache_Graphics extends Cache {
/**
* Cache URL prefix.
*
* Make sure that the cache URL prefix points to the $cache_dir, otherwise
* your links will be broken. Use setCacheURL to specify the cache_url and
* setCacheDir() for the cache_dir.
*
* @var string
* @see setCacheURL(), setCacheDir()
*/
var $cache_url = "";
/**
* Directory where cached files get stored.
* s
* Make sure that the cache_dir is writable and offers enough space. Check
* also if your cache_url points to the directory. Use setCacheDir() to set
* the variable.
*
* @var string
* @see setCacheDir(), setCacheURL()
*/
var $cache_dir = "";
/**
* Nameprefix of cached files.
*
* Per default the prefix "graphics_" gets used. You might use this
* for versioning or to ease (manual) clean ups.
*
* @var string
*/
var $cache_file_prefix = "graphics_";
/**
* Mapping from supported image type to a ImageType() constant.
*
* Referr to the PHP manual for more informations on ImageType()
*
* @var array
* @link http://www.php.net/ImageType
*/
var $imagetypes = array(
"gif" => IMG_GIF,
"jpg" => IMG_JPG,
"png" => IMG_PNG,
"wbmp" => IMG_WBMP
);
/**
* TODO: add docs
*/
function graphics_cache() {
$this->cache("cache_container_file", array("cache_dir" => $this->cache_dir, "filename_prefix" => $this->cache_file_prefix));
} // end constructor
/**
* Returns the content of a cached image file.
*
* This function can be used to send the image directly to the browser.
* Make sure that you send a correspondending header before sending the image itself.
*
* Always try to get the image from the cache before you compute it. See
* the class docs for an example.
*
* @param string Image-ID
* @param string Image type: gif, jpg, png, wbmp
* @return string Image file contents if a cached file exists otherwise an empty string
* @see cacheImage()
*/
function getImage($id, $format = "png") {
$id = $this->generateID(array("id" => $id, "format" => strtolower($format)));
return $this->get($id);
} // end func getImage
/**
* Returns an array with a link to the cached image and the image file path.
*
* Always try to get the image from the cache before you compute it. See
* the class docs for an example.
*
* @param string Image-ID
* @param string Image type: gif, jpg, png, wbmp
* @return array [ full path to the image file, image url ]
* @throw gerror
* @see cacheImageLink()
*/
function getImageLink($id, $format = "png") {
$id = $this->generateID(array("id" => $id, "format" => strtolower($format)));
if (!$this->container->idExists($id))
return array();
$file = $this->cache_url . $this->cache_file_prefix . $id;
return array($this->container->getFilename($id), $file);
} // end func getImageLink
/**
* Create an image from the given image handler, cache it and return the file content.
*
* Always try to retrive the image from the cache before you compute it.
*
* Warning: this function uses the output buffer. If you expect collisions
* modify the code.
*
* @param string Image-ID. Used as a part of the cache filename.
* Use md5() to generate a "unique" ID for your image
* based on characteristic values such as the color, size etc.
* @param string Image handler to create the image from.
* @param string Image type: gif, jpg, png, wbmp. Also used as filename suffix.
* If an unsupported type is requested the functions tries to
* fallback to a supported type before throwing an exeption.
* @return string Image content returned by ImageGIF/...
* @throws gerror
* @access public
* @see getImage()
*/
function cacheImage($id, &$img, $format = "png") {
if (!$id)
return new gerror("You must provide an ID for and image to be cached!");
$id = $this->generateID(array("id" => $id, "format" => strtolower($format)));
// Check if the requested image type is supported by the GD lib.
// If not, try a callback to the first available image type.
if (!isset($this->imagetypes[$format]) || !(ImageTypes() & $this->imagetypes[$format])) {
foreach ($this->imagetypes as $supported => $bitmask)
if (ImageTypes() & $bitmask)
new gerror("The build in GD lib does not support the image type $format. Fallback to $supported.");
else
return new gerror("Hmm, is you PHP build with GD support? Can't find any supported types.");
}
if ($image = $this->get($id))
return $image;
// save the image to the output buffer, write it to disk and
// return the image.
ob_end_clean();
ob_start();
// generate the image
$func = "Image" . strtoupper($format);
$func($img);
ImageDestroy($img);
ob_end();
$image = ob_get_contents();
ob_end_clean();
// save the generated image to disk
$this->save($id, $image, 0);
return $image;
} // end func cacheImage
/**
* Create an image from the given image handler, cache it and return a url and the file path of the image.
*
* Always try to retrive the image from the cache before you compute it.
*
* @param string Image-ID. Used as a part of the cache filename.
* Use md5() to generate a "unique" ID for your image
* based on characteristic values such as the color, size etc.
* @param string Image handler to create the image from.
* @param string Image type: gif, jpg, png, wbmp. Also used as filename suffix.
* If an unsupported type is requested the functions tries to
* fallback to a supported type before throwing an exeption.
* @return array [ full path to the image file, image url ]
* @throws gerror
* @access public
*/
function cacheImageLink($id, &$img, $format = "png") {
if (!$id)
return new gerror("You must provide an ID for and image to be cached!");
$id = $this->generateID(array("id" => $id, "format" => strtolower($format));
// Check if the requested image type is supported by the GD lib.
// If not, try a callback to the first available image type.
if (!isset($this->imagetypes[$format]) || !(ImageTypes() & $this->imagetypes[$format])) {
foreach ($this->imagetypes as $supported => $bitmask)
if (ImageTypes() & $bitmask)
new gerror("The build in GD lib does not support the image type $format. Fallback to $supported.");
else
return new gerror("Hmm, is you PHP build with GD support? Can't find any supported types.");
}
$url = $this->cache_url . $this->cache_file_prefix . $id;
$ffile = $this->container->getFilename($id);
if ($this->isCached($id) && !isExpired($id))
return array($ffile, $url)
$func = "Image" . strtoupper($format);
$func($img, $ffile);
ImageDestroy($img);
return array($ffile, $url);
} // end func cacheImageLink
/**
* Sets the URL prefix used when rendering HTML Tags.
*
* Make sure that the URL matches the cache directory,
* otherwise you'll get broken links.
*
* @param string
* @access public
* @see setCacheDir()
*/
function setCacheURL($cache_url) {
if ($cache_url && "/" != substr($cache_url, 1))
$cache_url .= "/";
$this->cache_url = $cache_url;
} // end func setCacheURL
/**
* Sets the directory where to cache generated Images
*
* @param string
* @access public
* @see setCacheURL()
*/
function setCacheDir($cache_dir) {
if ($cache_dir && "/" != substr($cache_dir, 1))
$cache_dir .= "/";
$this->cache_dir = $cache_dir;
$this->container->cache_dir = $cache_dir;
} // end func setCacheDir
} // end class Cache_Graphics
?>