Understanding Image Properties in PHP with the ImageMagick Package

The getImageProperties function in PHP returns an array of property keys available for an image.  To get these property values, you use getImageProperty function, giving it one of the available keys provided by the getImageProperties function result.  For some images, you may have a lot of properties and for some, you may have few.  The two that almost every image seems to have are "date:create" and "date:modify", but some images may have forty or more properties, some titled "exif:Compression", "photoshop:Credit", "jpeg:colorspace", "rdf:Alt", "stRef:documentID", and "xap:CreatorTool."  PNG files will also have properties like "png:IHDR.bit_depth" and "png:IHDR.width,height."  So far, it appears generally that GIF and BMP files, being simpler, have fewer properties, whereas JPEG and PNG files, being more complicated, have much wider array of properties.  It seems incredibly useful in document management.

And now, some sample code and results :

<?php

            // Author: holdoffhunger@gmail.com
   
        // Imagick Type
        // ---------------------------------------------

    $imagick_type = new Imagick();
   
        // Open File
        // ---------------------------------------------
       
    $file_to_grab = "image_workshop_directory/test.png";
   
    $file_handle_for_viewing_image_file = fopen($file_to_grab, 'a+');
   
        // Grab File
        // ---------------------------------------------

    $imagick_type->readImageFile($file_handle_for_viewing_image_file);
   
        // Get Image Properties
        // ---------------------------------------------
       
    $imagick_type_properties = $imagick_type->getImageProperties('*', FALSE);
   
        // Print Image Properties
        // ---------------------------------------------
   
    print("<pre>");
       
    print_r($imagick_type_properties);
   
        // Print Each Individual, Image Property
        // ---------------------------------------------
   
    foreach($imagick_type_properties as $value)
    {
        print("$value --- ");
        print($imagick_type->getImageProperty("$value"));
        print("<br><br>");
    }
               
    print("</pre>");

?>

Results of this done on a standard PNG image :

Array
(
    [0] => date:create
    [1] => date:modify
    [2] => png:cHRM                
    [3] => png:gAMA                
    [4] => png:IHDR.bit_depth      
    [5] => png:IHDR.color_type     
    [6] => png:IHDR.interlace_method
    [7] => png:IHDR.width,height   
    [8] => png:sRGB                
)
date:create --- 2012-05-19T18:26:45-05:00

date:modify --- 2012-05-19T18:26:45-05:00

png:cHRM                  --- chunk was found (see Chromaticity, above)

png:gAMA                  --- gamma=0.45455 (See Gamma, above)

png:IHDR.bit_depth        --- 8

png:IHDR.color_type       --- 2

png:IHDR.interlace_method --- 0

png:IHDR.width,height     --- 320, 320

png:sRGB                  --- intent=0 (See Rendering intent)

Official Function Page: http://www.php.net/manual/en/imagick.getimageproperties.php

// Note: All code appearing on the PHP Revolution blog by the blog owner is released under the Hacktivismo Enhanced-Source Software License Agreement (HESSLA), unless otherwise noted.  http://www.hacktivismo.com/about/hessla.php