Fix canvas editing GUI didn't work for Igor and later

CanvasElement.php

@@ -0,0 +1,73 @@
+<?php
+
+/**
+ * Class CanvasElement
+ *
+ * A custom element used for DokuWiki "Igor" and later, where old JavaScript injection won't work anymore.
+ *
+ * This is not a general-purpose element. It is strictly designed for sketchcanvas plugin.
+ */
+class CanvasElement extends dokuwiki\Form\InputElement
+{
+    /**
+     * @var string the actual text within the area
+     */
+    protected $text;
+
+    /**
+     * @param string $name The name of this form element
+     * @param string $label The label text for this element
+     */
+    public function __construct()
+    {
+        parent::__construct('canvas', 'canvas', '');
+    }
+
+        /**
+     * Get or set the element's value
+     *
+     * This is the preferred way of setting the element's value
+     *
+     * @param null|string $value
+     * @return string|$this
+     */
+    public function val($value = null)
+    {
+        if ($value !== null) {
+            $this->text = $value;
+            return $this;
+        }
+        return $this->text;
+    }
+
+    /**
+     * The HTML representation of this element
+     *
+     * @return string
+     */
+    protected function mainElementHTML()
+    {
+        $escText = '"' . str_replace(array("\r", "\n"), array('\r', '\n'), addslashes($this->text)) . '"';
+
+        $attrs = buildAttributes($this->attrs());
+
+        $canvasText = <<<EOT
+<canvas id="editcanvas" $attrs></canvas>
+<script type="text/javascript"><!--
+var skcanvas;
+document.addEventListener('DOMContentLoaded', function(){
+    skcanvas = new SketchCanvas(document.getElementById('editcanvas'), {editmode: true});
+    skcanvas.loadData($escText);
+    skcanvas.onUpdateData = function(data){
+        var wikitext = document.getElementById('wiki__text');
+        wikitext.value = data;
+    }
+});
+--></script>
+<input type="button" value="Load data from text" onclick="skcanvas.loadData(document.getElementById('wiki__text').value)">
+<textarea name="wikitext" id="wiki__text" class="edit" cols="80" rows="10">$this->text</textarea>
+EOT;
+        return $canvasText;
+    }
+
+}

action.php

@@ -9,6 +9,8 @@
 // must be run within Dokuwiki
 if (!defined('DOKU_INC')) die();
 
+require_once("CanvasElement.php");
+
 /**
  * Add scripts via an event handler
  */
@@ -22,6 +24,8 @@ public function register(Doku_Event_Handler $controller) {
 
        $controller->register_hook('HTML_SECEDIT_BUTTON', 'BEFORE', $this, 'editButton');
        $controller->register_hook('HTML_EDIT_FORMSELECTION', 'BEFORE', $this, 'editForm');
+       // After Igor
+       $controller->register_hook('EDIT_FORM_ADDTEXTAREA', 'BEFORE', $this, 'editFormNew');
        $controller->register_hook('ACTION_ACT_PREPROCESS', 'BEFORE', $this, 'handle_newfigure');
 
        $controller->register_hook('TOOLBAR_DEFINE', 'AFTER', $this, 'toolbarDefine');
@@ -121,6 +125,32 @@ public function editForm(Doku_Event $event, $param){
         }
     }
 
+    /**
+     * A
+     *
+     * @param Doku_Event $event
+     */
+    public function editFormNew(Doku_Event $event, $param){
+        global $TEXT;
+        if($event->data['target'] !== 'plugin_sketchcanvas')
+            return;
+        $event->preventDefault();
+
+        $event->data['media_manager'] = false;
+
+        $form =& $event->data['form'];
+        $canvasElem = new CanvasElement();
+        $canvasElem->val($TEXT);
+        $form->addElement($canvasElem);
+
+        // Pass wikitext through POSTs for previewing and saving
+        if(isset($_POST['editfigure__new'])) {
+            foreach($_POST['editfigure__new'] as $k => $v) {
+                $form->addHidden("editfigure__new[$k]", $v);
+            }
+        }
+    }
+
     /**
      * Add a toolbar button to add a new figure
      *