Add back the zoomin view

An alternative visualisation for the story list. It just shows the
currently selected tiddler, with smooth animations between tiddlers.

Not entirely finished yet; for instance, if you close the current
tiddler you get a blank screen until you select another tiddler.

core/modules/widgets/list/listviews/zoomin.js

@@ -0,0 +1,146 @@
+/*\
+title: $:/core/modules/widgets/list/listviews/zoomin.js
+type: application/javascript
+module-type: listview
+
+Zooms between individual tiddlers
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+var ZoominListView = function(listWidget) {
+	this.listWidget = listWidget;
+	this.storyNode = this.listWidget.renderer.domNode;
+	// Set the current tiddler
+	this.currentTiddler = this.listWidget.children[0];
+	// Make all the tiddlers position absolute, and hide all but the first one
+	this.storyNode.style.position = "relative";
+	for(var t=0; t<this.storyNode.children.length; t++) {
+		if(t) {
+			this.storyNode.children[t].style.display = "none";
+		}
+		this.storyNode.children[t].style.position = "absolute";
+	}
+};
+
+
+
+/*
+Find the first descendent node that is a <$view field="title"> widget
+*/
+function findTitleNode(node) {
+	var t,r;
+	// Return true if this node is a view widget with the field attribute set to "title"
+	if(node instanceof $tw.WikiRenderTree.prototype.rendererClasses.element) {
+		if(node.widget instanceof $tw.WikiRenderTree.prototype.rendererClasses.element.prototype.widgetClasses.view && node.attributes.field === "title") {
+			return node;	
+		}
+		if(node.widget.children) {
+			for(t=0; t<node.widget.children.length; t++) {
+				var r = findTitleNode(node.widget.children[t]);
+				if(r) {
+					return r;
+				}
+			}
+		}
+	} else {
+		if(node.children) {
+			for(t=0; t<node.children.length; t++) {
+				var r = findTitleNode(node.children[t]);
+				if(r) {
+					return r;
+				}
+			}
+		}
+	}
+	return null;
+}
+
+ZoominListView.prototype.insert = function(index) {
+	var listElementNode = this.listWidget.children[index],
+		targetElement = listElementNode.domNode;
+	// Make the newly inserted node position absolute and hidden
+	$tw.utils.setStyle(targetElement,[
+		{display: "none"},
+		{position: "absolute"}
+	]);
+};
+
+ZoominListView.prototype.navigateTo = function(historyInfo) {
+	var listElementIndex = this.listWidget.findListElementByTitle(0,historyInfo.title);
+	if(listElementIndex === undefined) {
+		return;
+	}
+	var listElementNode = this.listWidget.children[listElementIndex],
+		targetElement = listElementNode.domNode;
+	// Make the new tiddler be position absolute and visible so that we can measure it
+	$tw.utils.setStyle(targetElement,[
+		{position: "absolute"},
+		{display: "block"},
+		{transformOrigin: "0 0"},
+		{transform: "translateX(0px) translateY(0px) scale(1)"},
+		{transition: "none"},
+		{opacity: "0.0"}
+	]);
+	// Get the position of the source node, or use the centre of the window as the source position
+	var sourceBounds = historyInfo.fromPageRect || {
+			left: window.innerWidth/2 - 2,
+			top: window.innerHeight/2 - 2,
+			width: window.innerWidth/8,
+			height: window.innerHeight/8
+		};
+	// Try to find the title node in the target tiddler
+	var titleNode = findTitleNode(listElementNode) || listElementNode,
+		zoomBounds = titleNode.domNode.getBoundingClientRect();
+	// Compute the transform for the target tiddler to make the title lie over the source rectange
+	var targetBounds = targetElement.getBoundingClientRect(),
+		scale = sourceBounds.width / zoomBounds.width,
+		x = sourceBounds.left - targetBounds.left - (zoomBounds.left - targetBounds.left) * scale,
+		y = sourceBounds.top - targetBounds.top - (zoomBounds.top - targetBounds.top) * scale;
+	// Transform the target tiddler to its starting position
+	$tw.utils.setStyle(targetElement,[
+		{transform: "translateX(" + x + "px) translateY(" + y + "px) scale(" + scale + ")"}
+	]);
+	// Force layout
+	$tw.utils.forceLayout(targetElement);
+	// Apply the ending transitions with a timeout to ensure that the previously applied transformations are applied first
+	var self = this,
+		prevCurrentTiddler = this.currentTiddler;
+	this.currentTiddler = listElementNode;
+	// Transform the target tiddler to its natural size
+	$tw.utils.setStyle(targetElement,[
+		{transition: $tw.utils.roundTripPropertyName("transform") + " " + $tw.config.preferences.animationDurationMs + " ease-in-out, opacity " + $tw.config.preferences.animationDurationMs + " ease-out"},
+		{opacity: "1.0"},
+		{transform: "translateX(0px) translateY(0px) scale(1)"},
+		{zIndex: "500"},
+	]);
+	// Transform the previous tiddler out of the way and then hide it
+	if(prevCurrentTiddler && prevCurrentTiddler !== listElementNode) {
+		var scale = zoomBounds.width / sourceBounds.width;
+		x =  zoomBounds.left - targetBounds.left - (sourceBounds.left - targetBounds.left) * scale;
+		y =  zoomBounds.top - targetBounds.top - (sourceBounds.top - targetBounds.top) * scale;
+		$tw.utils.setStyle(prevCurrentTiddler.domNode,[
+			{transition: $tw.utils.roundTripPropertyName("transform") + " " + $tw.config.preferences.animationDurationMs + " ease-in-out, opacity " + $tw.config.preferences.animationDurationMs + " ease-out"},
+			{opacity: "0.0"},
+			{transformOrigin: "0 0"},
+			{transform: "translateX(" + x + "px) translateY(" + y + "px) scale(" + scale + ")"},
+			{zIndex: "0"}
+		]);
+		// Hide the tiddler when the transition has finished
+		setTimeout(function() {
+			if(self.currentTiddler !== prevCurrentTiddler) {
+				prevCurrentTiddler.domNode.style.display = "none";
+			}
+		},$tw.config.preferences.animationDuration);
+	}
+	// Scroll the target into view
+//	$tw.pageScroller.scrollIntoView(targetElement);
+};
+
+exports.zoomin = ZoominListView;
+
+})();