markgojs
Version:
Interactive diagrams, charts, and graphs, such as trees, flowcharts, orgcharts, UML, BPMN, or business diagrams
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HTML
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Incremental Tree</title>
<meta name="description" content="Incrementally grow a tree as each node is expanded for the first time." />
<!-- Copyright 1998-2019 by Northwoods Software Corporation. -->
<meta charset="UTF-8">
<script src="../release/go.js"></script>
<script src="../assets/js/goSamples.js"></script> <!-- this is only for the GoJS Samples framework -->
<script id="code">
function init() {
if (window.goSamples) goSamples(); // init for these samples -- you don't need to call this
var $ = go.GraphObject.make; // for conciseness in defining templates
var blues = ['#E1F5FE', '#B3E5FC', '#81D4FA', '#4FC3F7', '#29B6F6', '#03A9F4', '#039BE5', '#0288D1', '#0277BD', '#01579B'];
myDiagram =
$(go.Diagram, "myDiagramDiv", // must name or refer to the DIV HTML element
{
initialContentAlignment: go.Spot.Center,
layout: $(go.ForceDirectedLayout),
// moving and copying nodes also moves and copies their subtrees
"commandHandler.copiesTree": true, // for the copy command
"commandHandler.deletesTree": true, // for the delete command
"draggingTool.dragsTree": true, // dragging for both move and copy
"undoManager.isEnabled": true
});
// Define the Node template.
// This uses a Spot Panel to position a button relative
// to the ellipse surrounding the text.
myDiagram.nodeTemplate =
$(go.Node, "Spot",
{
selectionObjectName: "PANEL",
isTreeExpanded: false,
isTreeLeaf: false
},
// the node's outer shape, which will surround the text
$(go.Panel, "Auto",
{ name: "PANEL" },
$(go.Shape, "Circle",
{ fill: "whitesmoke", stroke: "black" },
new go.Binding("fill", "rootdistance", function(dist) {
dist = Math.min(blues.length - 1, dist);
return blues[dist];
})),
$(go.TextBlock,
{ font: "12pt sans-serif", margin: 5 },
new go.Binding("text", "key"))
),
// the expand/collapse button, at the top-right corner
$("TreeExpanderButton",
{
name: 'TREEBUTTON',
width: 20, height: 20,
alignment: go.Spot.TopRight,
alignmentFocus: go.Spot.Center,
// customize the expander behavior to
// create children if the node has never been expanded
click: function (e, obj) { // OBJ is the Button
var node = obj.part; // get the Node containing this Button
if (node === null) return;
e.handled = true;
expandNode(node);
}
}
) // end TreeExpanderButton
); // end Node
// create the model with a root node data
myDiagram.model = new go.TreeModel([
{ key: 0, color: blues[0], everExpanded: false }
]);
document.getElementById('zoomToFit').addEventListener('click', function() {
myDiagram.zoomToFit();
});
document.getElementById('expandAtRandom').addEventListener('click', function() {
expandAtRandom();
});
}
function expandNode(node) {
var diagram = node.diagram;
diagram.startTransaction("CollapseExpandTree");
// this behavior is specific to this incrementalTree sample:
var data = node.data;
if (!data.everExpanded) {
// only create children once per node
diagram.model.setDataProperty(data, "everExpanded", true);
var numchildren = createSubTree(data);
if (numchildren === 0) { // now known no children: don't need Button!
node.findObject('TREEBUTTON').visible = false;
}
}
// this behavior is generic for most expand/collapse tree buttons:
if (node.isTreeExpanded) {
diagram.commandHandler.collapseTree(node);
} else {
diagram.commandHandler.expandTree(node);
}
diagram.commitTransaction("CollapseExpandTree");
myDiagram.zoomToFit();
}
// This dynamically creates the immediate children for a node.
// The sample assumes that we have no idea of whether there are any children
// for a node until we look for them the first time, which happens
// upon the first tree-expand of a node.
function createSubTree(parentdata) {
var numchildren = Math.floor(Math.random() * 10);
if (myDiagram.nodes.count <= 1) {
numchildren += 1; // make sure the root node has at least one child
}
// create several node data objects and add them to the model
var model = myDiagram.model;
var parent = myDiagram.findNodeForData(parentdata);
var degrees = 1;
var grandparent = parent.findTreeParentNode();
while (grandparent) {
degrees++;
grandparent = grandparent.findTreeParentNode();
}
for (var i = 0; i < numchildren; i++) {
var childdata = {
key: model.nodeDataArray.length,
parent: parentdata.key,
rootdistance: degrees
};
// add to model.nodeDataArray and create a Node
model.addNodeData(childdata);
// position the new child node close to the parent
var child = myDiagram.findNodeForData(childdata);
child.location = parent.location;
}
return numchildren;
}
function expandAtRandom() {
var eligibleNodes = [];
myDiagram.nodes.each(function(n) {
if (!n.isTreeExpanded) eligibleNodes.push(n);
})
var node = eligibleNodes[Math.floor(Math.random() * (eligibleNodes.length))];
expandNode(node);
}
</script>
</head>
<body onload="init()">
<div id="sample">
<div id="myDiagramDiv" style="background-color: white; border: solid 1px black; width: 100%; height: 700px"></div>
<p><button id="zoomToFit">Zoom to Fit</button><button id="expandAtRandom">Expand random Node</button></p>
<p>
This diagram demonstrates the expansion of a tree where nodes are only created "on-demand",
when the user clicks on the "expand" Button.
As you expand the tree, it automatically performs a force-directed layout,
which will make some room for the additional nodes.
</p>
<p>
The data for each node is implemented by a JavaScript object held by the Diagram's model.
Each node data has an <b>everExpanded</b> property that indicates whether we have already
created all of its "child" data and added them to the model.
The <b>everExpanded</b> property defaults to false,
to match the initial value of <a>Node.isTreeExpanded</a> in the node template,
which specifies that the nodes start collapsed.
</p>
<p>
When the user clicks on the "expand" Button, the button click event handler finds the corresponding
data object by going up the visual tree to find the Node via the <a>GraphObject.part</a> property
and then getting the node data that the Node is bound to via <a>Part.data</a>.
If <b>everExpanded</b> is false, the code creates a random number of
child data for that node, each with a random <b>color</b> property.
Then the button click event handler changes the value of <b>Node.isExpandedTree</b>,
thereby expanding or collapsing the node.
</p>
<p>
Some initial node expansions result in there being no children at all.
In this case the Button is made invisible.
</p>
<p>
All changes are performed within a transaction.
You should always surround your code with calls to <a>Model.startTransaction</a> and <a>Model.commitTransaction</a>,
or the same methods on <a>Diagram</a>.
</p>
<p>
The diagram's <a>Diagram.layout</a> is an instance of <a>ForceDirectedLayout</a>.
The standard conditions under which the layout will be performed include
when nodes or links or group-memberships are added or removed from the model,
or when they change visibility.
In this case that means that when the user expands or collapses a node,
another force-directed layout occurs again, even upon repeated expansions or collapses.
</p>
</div>
</body>
</html>