Add support for action widgets

This is part of the groundwork for fixing #336

core/modules/widgets/action-navigate.js

@@ -0,0 +1,79 @@
+/*\
+title: $:/core/modules/widgets/action-navigate.js
+type: application/javascript
+module-type: widget
+
+Action widget to navigate to a tiddler
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+var Widget = require("$:/core/modules/widgets/widget.js").widget;
+
+var NavigateWidget = function(parseTreeNode,options) {
+	this.initialise(parseTreeNode,options);
+};
+
+/*
+Inherit from the base widget class
+*/
+NavigateWidget.prototype = new Widget();
+
+/*
+Render this widget into the DOM
+*/
+NavigateWidget.prototype.render = function(parent,nextSibling) {
+	this.computeAttributes();
+	this.execute();
+};
+
+/*
+Compute the internal state of the widget
+*/
+NavigateWidget.prototype.execute = function() {
+	this.actionTo = this.getAttribute("$to");
+	this.actionScroll = this.getAttribute("$scroll");
+};
+
+/*
+Refresh the widget by ensuring our attributes are up to date
+*/
+NavigateWidget.prototype.refresh = function(changedTiddlers) {
+	var changedAttributes = this.computeAttributes();
+	if(changedAttributes["$to"] || changedAttributes["$scroll"]) {
+		this.refreshSelf();
+		return true;
+	}
+	return this.refreshChildren(changedTiddlers);
+};
+
+/*
+Invoke the action associated with this widget
+*/
+NavigateWidget.prototype.invokeAction = function(triggeringWidget,event) {
+	var bounds = triggeringWidget && triggeringWidget.getBoundingClientRect && triggeringWidget.getBoundingClientRect(),
+		suppressNavigation = event.metaKey || event.ctrlKey || (event.button === 1);
+	if(this.actionScroll === "yes") {
+		suppressNavigation = false;
+	} else if(this.actionScroll === "no") {
+		suppressNavigation = true;
+	}
+	this.dispatchEvent({
+		type: "tm-navigate",
+		navigateTo: this.actionTo === undefined ? this.getVariable("currentTiddler") : this.actionTo,
+		navigateFromTitle: this.getVariable("storyTiddler"),
+		navigateFromNode: triggeringWidget,
+		navigateFromClientRect: bounds && { top: bounds.top, left: bounds.left, width: bounds.width, right: bounds.right, bottom: bounds.bottom, height: bounds.height
+		},
+		navigateSuppressNavigation: suppressNavigation
+	});
+	return true; // Action was invoked
+};
+
+exports["action-navigate"] = NavigateWidget;
+
+})();