ImageConversion/design/design.htm - zetacomponents - Git at Google

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 <h1 class="title">eZ publish Enterprise Component: ImageConversion, Design</h1>
 <div class="document" id="ez-publish-enterprise-component-imageconversion-design">
 <div class="section" id="introduction">
 <h1><a name="introduction">Introduction</a></h1>
 <p>Find more info about the requirenments on which this design is based on in the
 requirenments.txt.</p>
 </div>
 <div class="section" id="design-description">
 <h1><a name="design-description">Design description</a></h1>
 <div class="section" id="ezcimagemanager">
 <h2><a name="ezcimagemanager">ezcImageManager</a></h2>
 <p>The main class of the component is the ezcImageManager, which implements a
 singleton pattern, because only 1 manager is needed for all actions performed.
 The ezcImageManager dispatches the actions performed on images, holds the
 ezcImageHandler's (which actually perform the actions) and manages / defines
 the ezcImageTransformations which hold conversions and ezcImageFilter's.</p>
 <p>Since 1 filter/conversion can be performed by several ezcImageHandler's, the
 manager has a preference list, to determine, which ezcImageHandler to take for
 a conversion.</p>
 </div>
 <div class="section" id="ezcimagehandler">
 <h2><a name="ezcimagehandler">ezcImageHandler</a></h2>
 <p>This interface defines how the abstraction class for an image handler looks
 like. ezcImageHandler's utilize a given backend to perform conversion and
 filtering (using ezcImageFilter's). A ezcImageHandler knows by hisself, which
 filters he implements. The manager will ask it for supported filters to get an
 overview, which filters exist.</p>
 <p>To avoid reopening an image file for every operation the ezcImageHandler has
 load()/save() methods. An image must be saved before another ezcImageHandler
 can perform his actions on it.</p>
 </div>
 <div class="section" id="ezcimagefilter">
 <h2><a name="ezcimagefilter">ezcImageFilter</a></h2>
 <p>This class implements a storage container for filters to keep them better
 consistant than an array could do. Filters are created by the ezcImageManager
 or directly through a ezcImageHandler. An ezcImageFilter knows, to which
 handler he belongs and dispatches itself to the right handler, when applied.</p>
 </div>
 <div class="section" id="ezcimagetransformation">
 <h2><a name="ezcimagetransformation">ezcImageTransformation</a></h2>
 <p>ezcImageTransformation's abstract MIME types to allow the easy combination of
 conversions and filters which are necessary to get a desired image type.
 For conversions only the target MIME type is necessary. Beside that,
 ezcImageTransformation's have a reference, which either points to another ezcImageTransformation
 or to the special reference __original__ which is the image itself.</p>
 <p>If a ezcImageTransformation references another one, which does not exist, yet, it will
 be created, too. This enables one to create a chain of ezcImageTransformation's which
 will be processed.</p>
 <p>ezcImageTransformation's will be created on the fly, when the user requests them and not
 during startup of the manager. A created ezcImageTransformation will be cached in the
 manager for possible later use. Same applies to the filters utilized by the
 ezcImageTransformation.</p>
 <div class="section" id="example-1">
 <h3><a name="example-1">Example 1</a></h3>
 <table border="1" class="table">
 <colgroup>
 <col width="49%" />
 <col width="51%" />
 </colgroup>
 <tbody valign="top">
 <tr><td>Transformation:</td>
 <td>Preview</td>
 </tr>
 <tr><td>Reference:</td>
 <td>__original__</td>
 </tr>
 <tr><td>MIME:</td>
 <td><p class="first">image/JPEG</p>
 <p class="last">image/PNG</p>
 </td>
 </tr>
 <tr><td>Filters:</td>
 <td>scale 400x400</td>
 </tr>
 </tbody>
 </table>
 </div>
 <div class="section" id="example-2">
 <h3><a name="example-2">Example 2</a></h3>
 <table border="1" class="table">
 <colgroup>
 <col width="49%" />
 <col width="51%" />
 </colgroup>
 <tbody valign="top">
 <tr><td>Transformation:</td>
 <td>Thumbnail</td>
 </tr>
 <tr><td>Reference:</td>
 <td>Preview</td>
 </tr>
 <tr><td>MIME:</td>
 <td><p class="first">image/JPEG</p>
 <p class="last">image/PNG</p>
 </td>
 </tr>
 <tr><td>Filters:</td>
 <td><p class="first">scale 100x100</p>
 <p class="last">colorspace grey</p>
 </td>
 </tr>
 </tbody>
 </table>
 <p>Will scale down the image to 100x100 pixels and convert it to greyscale.</p>
 </div>
 <div class="section" id="example-3">
 <h3><a name="example-3">Example 3</a></h3>
 <table border="1" class="table">
 <colgroup>
 <col width="49%" />
 <col width="51%" />
 </colgroup>
 <tbody valign="top">
 <tr><td>Transformation:</td>
 <td>OldPhotos</td>
 </tr>
 <tr><td>Reference:</td>
 <td>original</td>
 </tr>
 <tr><td>MIME:</td>
 <td>image/JPEG</td>
 </tr>
 <tr><td>Filters:</td>
 <td><p class="first">colorspace grey</p>
 <p class="last">border 3</p>
 </td>
 </tr>
 </tbody>
 </table>
 <p>Will convert the inserted image to image/JPEG, reduce the colorspace to
 greyscale and add a border of 3 pixel.</p>
 <div class="section" id="l">
 <h4><a name="l">^L</a></h4>
 <p>Local Variables:
 mode: rst
 indent-tabs-mode: nil
 sentence-end-double-space: t
 fill-column: 70
 End:
 vim: et syn=rst tw=78 wrap</p>
 </div>
 </div>
 </div>
 </div>
 </div>
 </body>
 </html>
	<?xml version="1.0" encoding="utf-8" ?>
	<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
	<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
	<head>
	<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
	<meta name="generator" content="Docutils 0.3.5: http://docutils.sourceforge.net/" />
	<title>eZ publish Enterprise Component: ImageConversion, Design</title>
	<link rel="stylesheet" href="default.css" type="text/css" />
	</head>
	<body>
	<h1 class="title">eZ publish Enterprise Component: ImageConversion, Design</h1>
	<div class="document" id="ez-publish-enterprise-component-imageconversion-design">
	<div class="section" id="introduction">
	<h1><a name="introduction">Introduction</a></h1>
	<p>Find more info about the requirenments on which this design is based on in the
	requirenments.txt.</p>
	</div>
	<div class="section" id="design-description">
	<h1><a name="design-description">Design description</a></h1>
	<div class="section" id="ezcimagemanager">
	<h2><a name="ezcimagemanager">ezcImageManager</a></h2>
	<p>The main class of the component is the ezcImageManager, which implements a
	singleton pattern, because only 1 manager is needed for all actions performed.
	The ezcImageManager dispatches the actions performed on images, holds the
	ezcImageHandler's (which actually perform the actions) and manages / defines
	the ezcImageTransformations which hold conversions and ezcImageFilter's.</p>
	<p>Since 1 filter/conversion can be performed by several ezcImageHandler's, the
	manager has a preference list, to determine, which ezcImageHandler to take for
	a conversion.</p>
	</div>
	<div class="section" id="ezcimagehandler">
	<h2><a name="ezcimagehandler">ezcImageHandler</a></h2>
	<p>This interface defines how the abstraction class for an image handler looks
	like. ezcImageHandler's utilize a given backend to perform conversion and
	filtering (using ezcImageFilter's). A ezcImageHandler knows by hisself, which
	filters he implements. The manager will ask it for supported filters to get an
	overview, which filters exist.</p>
	<p>To avoid reopening an image file for every operation the ezcImageHandler has
	load()/save() methods. An image must be saved before another ezcImageHandler
	can perform his actions on it.</p>
	</div>
	<div class="section" id="ezcimagefilter">
	<h2><a name="ezcimagefilter">ezcImageFilter</a></h2>
	<p>This class implements a storage container for filters to keep them better
	consistant than an array could do. Filters are created by the ezcImageManager
	or directly through a ezcImageHandler. An ezcImageFilter knows, to which
	handler he belongs and dispatches itself to the right handler, when applied.</p>
	</div>
	<div class="section" id="ezcimagetransformation">
	<h2><a name="ezcimagetransformation">ezcImageTransformation</a></h2>
	<p>ezcImageTransformation's abstract MIME types to allow the easy combination of
	conversions and filters which are necessary to get a desired image type.
	For conversions only the target MIME type is necessary. Beside that,
	ezcImageTransformation's have a reference, which either points to another ezcImageTransformation
	or to the special reference __original__ which is the image itself.</p>
	<p>If a ezcImageTransformation references another one, which does not exist, yet, it will
	be created, too. This enables one to create a chain of ezcImageTransformation's which
	will be processed.</p>
	<p>ezcImageTransformation's will be created on the fly, when the user requests them and not
	during startup of the manager. A created ezcImageTransformation will be cached in the
	manager for possible later use. Same applies to the filters utilized by the
	ezcImageTransformation.</p>
	<div class="section" id="example-1">
	<h3><a name="example-1">Example 1</a></h3>
	<table border="1" class="table">
	<colgroup>
	<col width="49%" />
	<col width="51%" />
	</colgroup>
	<tbody valign="top">
	<tr><td>Transformation:</td>
	<td>Preview</td>
	</tr>
	<tr><td>Reference:</td>
	<td>__original__</td>
	</tr>
	<tr><td>MIME:</td>
	<td><p class="first">image/JPEG</p>
	<p class="last">image/PNG</p>
	</td>
	</tr>
	<tr><td>Filters:</td>
	<td>scale 400x400</td>
	</tr>
	</tbody>
	</table>
	</div>
	<div class="section" id="example-2">
	<h3><a name="example-2">Example 2</a></h3>
	<table border="1" class="table">
	<colgroup>
	<col width="49%" />
	<col width="51%" />
	</colgroup>
	<tbody valign="top">
	<tr><td>Transformation:</td>
	<td>Thumbnail</td>
	</tr>
	<tr><td>Reference:</td>
	<td>Preview</td>
	</tr>
	<tr><td>MIME:</td>
	<td><p class="first">image/JPEG</p>
	<p class="last">image/PNG</p>
	</td>
	</tr>
	<tr><td>Filters:</td>
	<td><p class="first">scale 100x100</p>
	<p class="last">colorspace grey</p>
	</td>
	</tr>
	</tbody>
	</table>
	<p>Will scale down the image to 100x100 pixels and convert it to greyscale.</p>
	</div>
	<div class="section" id="example-3">
	<h3><a name="example-3">Example 3</a></h3>
	<table border="1" class="table">
	<colgroup>
	<col width="49%" />
	<col width="51%" />
	</colgroup>
	<tbody valign="top">
	<tr><td>Transformation:</td>
	<td>OldPhotos</td>
	</tr>
	<tr><td>Reference:</td>
	<td>original</td>
	</tr>
	<tr><td>MIME:</td>
	<td>image/JPEG</td>
	</tr>
	<tr><td>Filters:</td>
	<td><p class="first">colorspace grey</p>
	<p class="last">border 3</p>
	</td>
	</tr>
	</tbody>
	</table>
	<p>Will convert the inserted image to image/JPEG, reduce the colorspace to
	greyscale and add a border of 3 pixel.</p>
	<div class="section" id="l">
	<h4><a name="l">^L</a></h4>
	<p>Local Variables:
	mode: rst
	indent-tabs-mode: nil
	sentence-end-double-space: t
	fill-column: 70
	End:
	vim: et syn=rst tw=78 wrap</p>
	</div>
	</div>
	</div>
	</div>
	</div>
	</body>
	</html>