Add Range widget (#2988)

* Adds a range widget 

Adds a range widget that supports all the range attributes on a input[type=range] element.  These include min max and increment.

* Update range.js

* Fix spaces vs tabs.

* Added documentation.

core/modules/widgets/range.js

@@ -0,0 +1,114 @@
+/*\
+title: $:/core/modules/widgets/range.js
+type: application/javascript
+module-type: widget
+
+Range widget
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+var Widget = require("$:/core/modules/widgets/widget.js").widget;
+
+var RangeWidget = function(parseTreeNode,options) {
+	this.initialise(parseTreeNode,options);
+};
+
+/*
+Inherit from the base widget class
+*/
+RangeWidget.prototype = new Widget();
+
+/*
+Render this widget into the DOM
+*/
+RangeWidget.prototype.render = function(parent,nextSibling) {
+	// Save the parent dom node
+	this.parentDomNode = parent;
+	// Compute our attributes
+	this.computeAttributes();
+	// Execute our logic
+	this.execute();
+	// Create our elements
+	this.inputDomNode = this.document.createElement("input");
+	this.inputDomNode.setAttribute("type","range");
+	this.inputDomNode.setAttribute("class",this.elementClass);
+	if(this.minValue){
+		this.inputDomNode.setAttribute("min", this.minValue);
+	}
+	if(this.maxValue){
+		this.inputDomNode.setAttribute("max", this.maxValue);
+	}
+	if(this.increment){
+		this.inputDomNode.setAttribute("step", this.increment);
+	}
+	this.inputDomNode.value = this.getValue();
+
+
+	// Add a click event handler
+	$tw.utils.addEventListeners(this.inputDomNode,[
+		{name: "input", handlerObject: this, handlerMethod: "handleChangeEvent"}
+	]);
+	// Insert the label into the DOM and render any children
+	parent.insertBefore(this.inputDomNode,nextSibling);
+	this.domNodes.push(this.inputDomNode);
+};
+
+RangeWidget.prototype.getValue = function() {
+	var tiddler = this.wiki.getTiddler(this.tiddlerTitle),
+		value   = this.defaultValue;
+	if(tiddler) {
+		if($tw.utils.hop(tiddler.fields,this.tiddlerField)) {
+			value = tiddler.fields[this.tiddlerField] || "";
+		} else {
+			value = this.defaultValue || "";
+		}
+	}
+	return value;
+};
+
+RangeWidget.prototype.handleChangeEvent = function(event) {
+	this.wiki.setText(this.tiddlerTitle ,this.tiddlerField, null,this.inputDomNode.value);
+};
+
+/*
+Compute the internal state of the widget
+*/
+RangeWidget.prototype.execute = function() {
+	// Get the parameters from the attributes
+	this.tiddlerTitle = this.getAttribute("tiddler",this.getVariable("currentTiddler"));
+	this.tiddlerField = this.getAttribute("field");
+	this.minValue = this.getAttribute("min");
+	this.maxValue = this.getAttribute("max");
+	this.increment = this.getAttribute("increment");
+	this.defaultValue = this.getAttribute("default");
+	this.elementClass = this.getAttribute("class","");
+	// Make the child widgets
+	this.makeChildWidgets();
+};
+
+/*
+Selectively refreshes the widget if needed. Returns true if the widget or any of its children needed re-rendering
+*/
+RangeWidget.prototype.refresh = function(changedTiddlers) {
+	var changedAttributes = this.computeAttributes();
+	if(changedAttributes.tiddler || changedAttributes.field || changedAttributes['min'] || changedAttributes['max'] || changedAttributes['increment'] || changedAttributes["default"] || changedAttributes["class"]) {
+		this.refreshSelf();
+		return true;
+	} else {
+		var refreshed = false;
+		if(changedTiddlers[this.tiddlerTitle]) {
+			this.inputDomNode.checked = this.getValue();
+			refreshed = true;
+		}
+		return this.refreshChildren(changedTiddlers) || refreshed;
+	}
+};
+
+exports.range = RangeWidget;
+
+})();

editions/tw5.com/tiddlers/widgets/RangeWidget.tid

@@ -0,0 +1,22 @@
+caption: range
+created: 20171102134825376
+modified: 20171102134928964
+tags: Widgets
+title: RangeWidget
+
+! Introduction
+
+The range widget displays an HTML `<input type="range">` that reflects a given tiddler field numeric value. Adjusting the radio button sets to the tiddler field to the value.
+
+! Content and Attributes
+
+The content of the `<$range>` widget is ignored.
+
+|!Attribute |!Description |
+|tiddler |Title of the tiddler to manipulate (defaults to the [[current tiddler|Current Tiddler]]) |
+|field |The field of the //tiddler// bound to the radio button|
+|min |The minimum value to be able to be set by the `<$range>` widget.|
+|max |The maximum value to be able to be set by the `<$range>` widget.|
+|increment |The minimum amount by which a value may be changed.  Defaults to 1.|
+|default |The default value displayed if the field is missing or empty.|
+|class |CSS classes to be assigned to the label around the radio button |