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