Issue #6: Preserve width attributes

Conflicts:
	version.php

classes/image.php

@@ -42,6 +42,17 @@
  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class image {
+
+    /**
+     * Always preserve a width attribute already in an image tag.
+     */
+    const WIDTHATTPRESERVE = 0;
+
+    /**
+     * Only preserve a width attribute if it's less than the maximum width.
+     */
+    const WIDTHATTPRSERVELTMAX = 1;
+
     /**
      * Shame that this was nicked from gdlib.php and that there isn't a function I could have used from there.
      * Creates a resized version of image and stores copy in file area

filter.php

@@ -51,6 +51,11 @@ public function __construct(context $context, array $localconfig) {
         require_once($CFG->libdir.'/filelib.php');
 
         $this->config = get_config('filter_imageopt');
+        if (!isset($this->config->widthattribute)) {
+            $this->config->widthattribute = image::WIDTHATTPRSERVELTMAX;
+        }
+        $this->config->widthattribute = intval($this->config->widthattribute);
+
         parent::__construct($context, $localconfig);
     }
 
@@ -124,6 +129,25 @@ private function imageopturl($file) {
     private function img_add_width_height($img, $width, $height) {
         $maxwidth = $this->config->maxwidth;
 
+        if (stripos($img, ' width') !== false) {
+            if ($this->config->widthattribute === image::WIDTHATTPRSERVELTMAX) {
+                // Note - we cannot check for percentage widths as they are responsively variable.
+                $regex = '/(?<=\<img)(?:.*)width(?:\s|)=(?:"|\')(\d*)(?:px|)(?:"|\')/';
+                $matches = [];
+                preg_match($regex, $img, $matches);
+                if (!empty($matches[1])) {
+                    $checkwidth = $matches[1];
+                    if ($checkwidth < $maxwidth) {
+                        // This image already has a width attribute and that width is less than the max width.
+                        return $img;
+                    }
+                }
+            } else {
+                // Return img tag as is with width preserved.
+                return $img;
+            }
+        }
+
         if ($width > $maxwidth) {
             $ratio = $height / $width;
             $width = $maxwidth;

lang/en/filter_imageopt.php

@@ -28,3 +28,7 @@
 $string['donotloadonvisible'] = 'No placeholding, load immediately';
 $string['loadonvisibilityall'] = 'All images';
 $string['loadonvisibilityafter'] = 'After {$a} image(s)';
+$string['widthattribute'] = 'Image width attribute';
+$string['widthattributedesc'] = 'How should existing image width attributes be dealt with';
+$string['widthattpreserve'] = 'Preserve user width attributes in all cases';
+$string['widthattpreserveltmax'] = 'Preserve user width attributes only if less than maximum width';

settings.php

@@ -23,6 +23,11 @@
 
 defined('MOODLE_INTERNAL') || die;
 
+// You can never trust autoloading in settings.php!
+require_once(__DIR__.'/classes/image.php');
+
+use filter_imageopt\image;
+
 if ($ADMIN->fulltree) {
     $choices = [
         480 => '480',
@@ -42,4 +47,12 @@
     $choices[999] = get_string('donotloadonvisible', 'filter_imageopt');
     $settings->add(new admin_setting_configselect('filter_imageopt/loadonvisible', get_string('loadonvisible', 'filter_imageopt'),
         get_string('loadonvisibledesc', 'filter_imageopt'), 5, $choices));
+
+    $choices = [
+        image::WIDTHATTPRSERVELTMAX => get_string('widthattpreserveltmax', 'filter_imageopt'),
+        image::WIDTHATTPRESERVE => get_string('widthattpreserve', 'filter_imageopt')
+    ];
+    $settings->add(new admin_setting_configselect('filter_imageopt/widthattribute',
+        get_string('widthattribute', 'filter_imageopt'),
+        get_string('widthattributedesc', 'filter_imageopt'), image::WIDTHATTPRSERVELTMAX, $choices));
 }

version.php

@@ -22,8 +22,8 @@
  */
 defined('MOODLE_INTERNAL') || die();
 
-$plugin->version   = 2016121301;
+$plugin->version   = 2017110300;
 $plugin->requires  = 2011111500;
 $plugin->component = 'filter_imageopt';
-$plugin->maturity  = MATURITY_ALPHA;
-$plugin->release   = '3.2.0.0';
+$plugin->maturity  = MATURITY_BETA;
+$plugin->release   = '3.4.0.0';