EZ-Components

2026-07-22 01:12:17 +00:00 · 2009-02-17 15:27:43 +00:00
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+eZ Components - ImageAnalysis
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. contents:: Table of Contents
+
+Introduction
+============
+
+The ImageAnalysis component allows you to analyze certain image attributes.
+
+Class overview
+==============
+
+ezcImageAnalyzer is the main class for this component. It is responsible for
+handling the analysis of image files, as well as caching the results.
+
+Usage
+=====
+
+MIME type determination
+-----------------------
+
+The following example simply detects the MIME type of an image and prints it:
+
+.. include:: tutorial_example_01.php
+   :literal:
+
+On line 5, a new ezcImageAnalyzer object is instantiated. This must be done for
+each image to be analyzed. In line 7, the MIME type is determined. Here is an
+example image including the output:
+
+.. image:: img/imageanalysis_example_01.jpg
+   :alt: Simple JPEG image.
+
+::
+
+    Image has MIME type <image/jpeg>
+
+Extracting further data
+-----------------------
+
+Aside from the MIME type, ImageAnalysis can extract other image information. 
+The following example demonstrates this:
+
+.. include:: tutorial_example_02.php
+   :literal:
+
+The example is basically the same as the first one, except that more data is requested
+from ezcImageAnalyzer (lines 8 to 11). The analysis of additional data
+begins on line 9. After that, the data is cached in the ezcImageAnalyzer object.
+
+The width, height and size values are available for every analyzable image.
+A comment is not always available. If an image property is not available, the
+output will be some sensible default value (such as n/a). (Note that the
+availability of some data also depends on the availability of PHP's Exif
+extension.)
+
+The example image and printed output is shown below:
+
+.. image:: img/imageanalysis_example_02.jpg
+
+::
+
+    Image data:
+    MIME type:      image/jpeg
+    Width:          380 px
+    Height:         285 px
+    Filesize:       25984 b
+    Comment:        n/a
+
+
+Configuring handlers
+--------------------
+
+Like ezcImageConverter, ezcImageAnalyzer is based on handler classes, which
+allow it to utilize different back-ends for image analysis. The currently
+implemented handlers are:
+
+ezcImageAnalyzerPhpHandler
+  This uses PHP's getimagesize() function (which does not require the GD
+  extension!) and can optionally use PHP's Exif extension.
+
+ezcImageAnalyzerImagemagickHandler
+  Here `ImageMagick`_'s "identify" program is used.
+
+Both handlers are activated by default and are capable of determining if their
+preconditions are fulfilled.
+
+You might need to configure a handler, if for example the path to the
+ImageMagick_ "identify" binary is not available in the $PATH environment
+variable. The following example shows how this is possible and what else can be
+configured for the handlers:
+
+.. _ImageMagick: http://www.imagemagick.org/script/index.php
+
+.. include:: tutorial_example_03.php
+   :literal:
+
+Basically, the code is the same as in example 2, except that ezcImageAnalyzer
+is being configured to only use its ImageMagick handler and
+not the PHP handler. In addition, the location of the "identify" binary is
+explicitly set. See the results below:
+
+.. image:: img/imageanalysis_example_03.jpg
+
+::
+    
+    Image data:
+    MIME type:      image/jpeg
+    Width:          320 px
+    Height:         240 px
+    Filesize:       26365 b
+    Comment:        San Francisco airport, October 2005.
+
+More information
+================
+
+For more information, see the ezcImageAnalyzer API documentation.
+
+
+..
+   Local Variables:
+   mode: rst
+   fill-column: 79
+   End: 
+   vim: et syn=rst tw=79