ImageManager :: Adventure PHP Framework (APF)

ImageManager

The documentation for this component relevant until revision 1.8 can be found on ImageManager (until 1.8).

The ImageManager component implements methods to edit pictures. Here JPEG and GIF are as well supported as PNG images if the PHP GDLib is available in the correct version. To use the ImageManager it must be included into the current application using

PHP-Code

import('tools::image','ImageManager');

before instanciating it. For image handling purposes, the two static methods

showImageAttributes() and
resizeImage()

are available. The methods available previous to release 1.9 are documented on the old ImageManager documentation page.

1. Displaying image attributes

The method showImageAttributes() is intended to return the attributes of an image. It returns an associative array or the value of a dedicated attribute. Hence, the code

PHP-Code

import('tools::image','ImageManager');
$image = './images/my_new_dog.png';
echo printObject(ImageManager::getImageAttributes($image));

creates the output

Code

Array
(
    [width] => 180
    [height] => 104
    [type] => png
    [mimetype] => image/png
    [bitdepth] => 8
)

If the second argument contains the name of the desired attribute, the return value contains the value of the attribute directly. Thus, the code

PHP-Code

import('tools::image','ImageManager');
$image = './images/my_new_dog.png';
echo ImageManager::getImageAttributes($image,'type');

creates the output

Code

png

The following list describes the attributes available:

width: the width of the image
height: the height of the image
type: the type of the image
mimetype: the mime type of the image
bitdepth: the bitdepth of the image
colormode: the color mode (RGB or CMYK)

2. Resize images

In order to change the dimensions of an image, the resizeImage() method can be used. To achieve this, the source image and the target dimensions must be applied as arguments. If no target image is given or the param contains the value null, the resized image is flushed to STDOUT. As an optional parameter, the quality of JPEG images can be set. The following code snippet shows, how the ImageManager can be used to generate thumbnails:

PHP-Code

import('tools::image','ImageManager');
$image = './images/my_new_dog.png';
$picto = './images/my_new_dog_small.png';
$attributes = ImageManager::getImageAttributes($image);
$width = round((int)$attributes['width'] / 10,0); // resize to 10%
$height = round((int)$attributes['height'] / 10,0); // resize to 10%
ImageManager::resizeImage($image,$width,$height,$picto);

If a JPEG image should be flushed to STDOUT after resizing, but the quality of the target image should be set to a value of 90, this can be done with the following code snippet:

PHP-Code

import('tools::image','ImageManager');
$image = './images/my_old_dog.jpg';
ImageManager::resizeImage($image,$width,$height,null,90);

3. Application sample: ImageResizer

A typical application case for the ImageManager ist the delivery of images with dynamic sizes via a front controller action. The following code depicts the content of the run() method of the action, that additionally caches images, that were already delivered:

PHP-Code

// include the necessary libraries
import('tools::image','ImageManager');

// gather the relevant params from the action input
$image = urldecode($this->__Input->getAttribute('image'));
$ext = $this->__Input->getAttribute('ext');
$size = (int)$this->__Input->getAttribute('size');
$path = $this->__Input->getAttribute('path');

// check, if all attributes are there
$imagePath = $path.'/'.$image.'.'.$ext;
if($image == null){
   trigger_error('[ShowImageAction::run()] No image name ("image") given
   in frontcontroller input params!',E_USER_ERROR);
   exit(1);
}
if($ext == null){
   trigger_error('[ShowImageAction::run()] No image extenstion information
   ("ext") given in frontcontroller input params!',E_USER_ERROR);
   exit(1);
}
if(!file_exists($imagePath)){
   trigger_error('[ShowImageAction::run()] The image "'.$imagePath.'" does not
   exist. Please check your action call concerning the path, the name and
   the extention of the image!');
   exit(1);
}

// gather the image attributes
$attributes = ImageManager::getImageAttributes($imagePath);

// resize image
if($size === 100){
   $imageSource = file_get_contents($imagePath);
}
else{

   // calculate the new width and height
   $width = round(($size / 100) * intval($attributes['width']),0);
   $height = round(($size / 100) * intval($attributes['height']),0);

   // get cache manager
   $cMF = &$this->__getServiceObject('tools::cache','CacheManagerFabric');
   $cM = &$cMF->getCacheManager('imageresizer');

   // try to load the file from cache
   $cacheKey = md5($imagePath.$size);
   $imageSource = $cM->getFromCache($cacheKey);
   if($imageSource === null){

      // resize image and catch the output
      ob_start();
      ImageManager::resizeImage($imagePath,$width,$height);
      $imageSource = ob_get_contents();
      ob_end_clean();

      // write to cache
      $cM->writeToCache($cacheKey,$imageSource);

   }

}

// send header
header('Content-Type: '.$attributes['mimetype']);
header('Content-disposition: inline; filename="'.$image.'.'.$ext.'"');
header('Content-Transfer-Encoding: binary');
header('Content-Length: '.strlen($imageSource));

// stream image and exit
echo $imageSource;
exit(0);

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ImageManager

1. Displaying image attributes

2. Resize images

3. Application sample: ImageResizer

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