Added support for custom convolutions. Fix #49.

webroot/img.php

@@ -465,19 +465,35 @@ verbose("json = $outputFormat");
 
 /**
  * dpr - change to get larger image to easier support larger dpr, such as retina.
- */
+ */ 
 $dpr = get(array('ppi', 'dpr', 'device-pixel-ratio'), 1);
 
 verbose("dpr = $dpr");
 
 
 
+/**
+ * Create the class for the image.
+ */
+require $config['cimage_class'];
+
+$img = new CImage();
+$img->setVerbose($verbose);
+
+
+
 /**
  * convolve - image convolution as in http://php.net/manual/en/function.imageconvolution.php
  */
 $convolve = get('convolve', null);
 
-verbose("convolve = $convolve");
+// Check if the convolve is matching an existing constant 
+if ($convolve && isset($config['convolution_constant'])) {
+    $img->addConvolveExpressions($config['convolution_constant']);
+    verbose("convolve = " . print_r($config['convolution_constant'], 1));
+}
+
+verbose("convolve = " . print_r($convolve, 1));
 
 
 
@@ -502,14 +518,10 @@ EOD;
 
 
 /**
- * Create and output the image
+ * Load, process and output the image
  */
-require $config['cimage_class'];
 
-$img = new CImage();
-
-$img->setVerbose($verbose)
-    ->log("Incoming arguments: " . print_r(verbose(), 1))
+$img->log("Incoming arguments: " . print_r(verbose(), 1))
     ->setSource($srcImage, $config['image_path'])
     ->setOptions(
         array(

webroot/img_config.php

@@ -11,14 +11,16 @@ return array(
      * Paths, where are all the stuff I should use? 
      * Append ending slash on directories.
      */
-    'cimage_class' =>  __DIR__.'/../CImage.php',
-    'image_path'   =>  __DIR__.'/img/',
-    'cache_path'   =>  __DIR__.'/../cache/',
+    'cimage_class' =>  __DIR__ . '/../CImage.php',
+    'image_path'   =>  __DIR__ . '/img/',
+    'cache_path'   =>  __DIR__ . '/../cache/',
 
 
 
     /**
      * Check that the imagefile is a file below 'image_path' using realpath().
+     * Security constraint to avoid reaching images outside image_path. 
+     * This means that symbolic links to images outside the image_path will fail.
      */
     'image_path_constraint' => true,
 
@@ -32,7 +34,7 @@ return array(
 
 
     /**
-     * Set default timezone, it defaults to UTC if not specified otherwise.
+     * Set default timezone, it defaults to UTC if not specified.
      * 
      */
     //'default_timezone'     => 'UTC',
@@ -40,7 +42,9 @@ return array(
 
 
     /**
-     * Max image dimensions,
+     * Max image dimensions, larger dimensions results in 404.
+     * This is basically a security constraint to avoid using resources on creating 
+     * large (unwanted) images.
      * 
      */
     'max_width'     => 2000,
@@ -65,9 +69,33 @@ return array(
 
 
 
+    /**
+     * Create custom convolution expressions, matrix 3x3, divisor and 
+     * offset.
+     */
+    'convolution_constant' => array(
+        'edge'         => '-1,-1,-1, -1,8,-1, -1,-1,-1, 9, 0',
+        'edge-alt'     => '0,1,0, 1,-4,1, 0,1,0, 1, 0',
+        'draw'         => '0,-1,0, -1,5,-1, 0,-1,0, 0, 0',
+        'sharpen-alt'  => '0,-1,0, -1,5,-1, 0,-1,0, 1, 0',
+        'emboss-alt'   => '-2,-1,0, -1,1,1, 0,1,2, 1, 0',
+        'mean'         => '1,1,1, 1,1,1, 1,1,1, 9, 0',
+        'motion'       => '1,0,0, 0,1,0, 0,0,1, 3, 0',
+    ),
+
+
+
     /**
      * Predefined size constants. 
-     * 
+     *
+     * These can be used together with &width or &height to create a constant value 
+     * for a width or height where can be changed in one place.
+     * Useful when your site changes its layout or if you have a grid to fit images into.
+     *
+     * Example: 
+     *  &width=w1  // results in width=613
+     *  &width=c2  // results in spanning two columns with a gutter, 30*2+10=70
+     *  &width=c24 // results in spanning whole grid 24*30+((24-1)*10)=950
      */
     'size_constant' => function () {
 
@@ -115,8 +143,10 @@ return array(
     'error_reporting' => function () {
         error_reporting(-1);              // Report all type of errors
         ini_set('display_errors', 1);     // Display all errors
-        ini_set('output_buffering', 0);   // Do not buffer outputs, write directly
         set_time_limit(20);
         ini_set('gd.jpeg_ignore_warning', 1); // Ignore warning of corrupt jpegs
+        if (!extension_loaded('gd')) {
+            throw new Exception("Extension gd is nod loaded.");
+        }
     },
 );

webroot/test/test_issue49.php

@@ -0,0 +1,38 @@
+<?php
+// Include config for all testcases
+include __DIR__ . "/config.php";
+
+
+
+// The title of the test case
+$title = "Testing issue 49 - flexible convolution";
+
+
+
+// Provide a short description of the testcase.
+$description = "Creating shortcuts to custom convolutions by using configurable list of constant convolutions.";
+
+
+
+// Use these images in the test
+$images = array(
+    'kodim08.png',
+);
+
+
+
+// For each image, apply these testcases 
+$testcase = array(
+    '&nc&width=400&convolve=lighten',
+    '&nc&width=400&convolve=darken',
+    '&nc&width=400&convolve=sharpen',
+    '&nc&width=400&convolve=emboss',
+    '&nc&width=400&convolve=blur',
+    '&nc&width=400&convolve=blur:blur',
+    '&nc&width=400&convolve=blur:blur:blur:blur',
+);
+
+
+
+// Apply testcases and present results
+include __DIR__ . "/template.php";