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Interactive diagrams, charts, and graphs, such as trees, flowcharts, orgcharts, UML, BPMN, or business diagrams
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<h1><span>GraphObject Manipulation</span></h1>
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<h2 id="ProgrammaticallyInteractiveWithNodes">Programmatically interacting with Nodes</h2>
<p>
This guide will show you some basic ways of programmatically interacting with <b>GoJS</b> nodes and links and model data.
Throughout this page, we will use the following diagram setup as our starting point:
</p>
<pre class="lang-js">
var $ = go.GraphObject.make;
myDiagram =
$(go.Diagram, "myDiagramDiv",
{ "undoManager.isEnabled": true });
// define a simple Node template
myDiagram.nodeTemplate =
$(go.Node, "Auto",
$(go.Shape, "Rectangle",
// don't draw any outline
{ stroke: null },
// the Shape.fill comes from the Node.data.color property
new go.Binding("fill", "color")),
$(go.TextBlock,
// leave some space around larger-than-normal text
{ margin: 6, font: "18px sans-serif" },
// the TextBlock.text comes from the Node.data.key property
new go.Binding("text", "key"))
);
myDiagram.model = new go.GraphLinksModel(
[
{ key: "Alpha", color: "lightblue" },
{ key: "Beta", color: "orange" },
{ key: "Gamma", color: "lightgreen" },
{ key: "Delta", color: "pink" }
]);</pre>
<p>
The code produces this Diagram:
</p>
<!-- LIVE -->
<div id="myDiagramDiv" class="diagramStyling" style="width:700px; height:150px"></div>
<script>
function setupDiagram(divname) {
var $ = go.GraphObject.make;
var myDiagram = $(go.Diagram, divname,
{ "undoManager.isEnabled": true });
// define a simple Node template
myDiagram.nodeTemplate =
$(go.Node, "Auto",
$(go.Shape, "Rectangle",
{ stroke: null },
new go.Binding("fill", "color")),
$(go.TextBlock,
{ margin: 6, font: "18px sans-serif" },
new go.Binding("text", "key"))
);
myDiagram.model = new go.GraphLinksModel(
[
{ key: "Alpha", color: "lightblue" },
{ key: "Beta", color: "orange" },
{ key: "Gamma", color: "lightgreen" },
{ key: "Delta", color: "pink" }
]);
return myDiagram;
}
setupDiagram("myDiagramDiv");
</script>
<h2 id="FindingSingleNodesDiagramFindNodeForKey">Finding single nodes: Diagram.findNodeForKey</h2>
<p>
You can use <code>Diagram.findNodeForKey(key)</code> to get a reference to a Node in JavaScript.
Key values in <b>GoJS</b> can be either strings or numbers.
You can then use the Node reference to inspect and manipulate the Node.
</p>
<pre class="lang-js">
var node = myDiagram.findNodeForKey("Alpha");
// Selects the node programmatically, rather than clicking interactively:
myDiagram.select(node);
// Outputs a JavaScript object in the developer console window.
// The format of what is output will differ per browser, but is essentially the object:
// { key: "Alpha", color: "lightblue" }
// plus some internal implementation details.
console.log(node.data);</pre>
<!-- LIVE -->
<div id="myDiagramDiv2" class="diagramStyling" style="width:700px; height:150px"></div>
<script>
var myDiagram = setupDiagram("myDiagramDiv2");
var node = myDiagram.findNodeForKey("Alpha");
myDiagram.select(node);
if (window.console) console.log(node.data);
</script>
<p>
However <code>findNodeForKey</code> may return <code>null</code> if no node data uses that key value.
Also, it only looks at the model data to find a node data that uses the given key value,
from which it finds the corresponding Node in the Diagram.
It does not look at the text values of any TextBlocks that are within the Nodes,
so it can work even if no text is shown at all.
</p>
<p>
Once you have a <code>Node</code>, you can get its key either via the <code>Node.key</code> property or
by looking at its data: <code>someNode.data.key</code>, just as you can look at any of the data properties.
</p>
<h2 id="CollectionsOfNodesAndLinks">Collections of Nodes and Links</h2>
<p>
Diagrams have several properties and methods that return iterators describing collections of Parts.
Both Nodes and Links are kinds of Parts.
<code>Diagram.nodes</code> and <code>Diagram.links</code> return iterators of all Nodes and Links in the Diagram, respectively.
<code>Diagram.selection</code> returns an iterator of selected Parts
(both selected Nodes and selected Links).
</p>
<p>
There are also more specific methods for common operations, such as <code>Diagram.findTreeRoots()</code>
which returns an iterator of all top-level Nodes that have no parent nodes.
</p>
<p>
This next example uses <code>Diagram.nodes</code> and shows how to iterate over the collection.
</p>
<pre class="lang-js">
// Calling Diagram.commit executes the given function between startTransaction and commitTransaction
// calls. That automatically updates the display and allows the effects to be undone.
myDiagram.commit(function(d) { // this Diagram
// iterate over all nodes in Diagram
d.nodes.each(function(node) {
if (node.data.key === "Beta") continue; //skip Beta, just to contrast
node.scale = 0.4; // shrink each node
});
}, "decrease scale");</pre>
<p>As a result we have very scaled-down nodes, except for Beta:</p>
<!-- LIVE -->
<div id="myDiagramDiv3" class="diagramStyling" style="width:700px; height:150px"></div>
<script>
var myDiagram = setupDiagram("myDiagramDiv3");
myDiagram.commit(function(d) { // this Diagram
// iterate over all nodes in Diagram
d.nodes.each(function(node) {
if (node.data.key === "Beta") return; //skip Beta, just to contrast
node.scale = 0.4; // shrink each node
});
}, "decrease scale");
</script>
<h2 id="NamedGraphObjectsAndPanelFindObject">Named GraphObjects and Panel.findObject</h2>
<p>
Often we want to manipulate a property that belongs to one of the Node's elements,
perhaps an element arbitrarily deep in the template.
In our example Diagram, each Node has one Shape,
and if we want to change the color of this Shape directly we would need a reference to it.
To make it possible to find, we can give that Shape a name:
</p>
<pre class="lang-js">
myDiagram.nodeTemplate =
$(go.Node, "Auto",
$(go.Shape, "Rectangle",
{ stroke: null, name: "SHAPE" }, // added the name property
new go.Binding("fill", "color")),
$(go.TextBlock,
{ margin: 6, font: "18px sans-serif" },
new go.Binding("text", "key"))
);</pre>
<p>
Names allow us to easily find GraphObjects inside of Panels
(all Nodes are also Panels) using <code>Panel.findObject</code>,
which will search the visual tree of a Panel starting at that panel.
So when we have a reference to a Node, we can call <code>someNode.findObject("SomeName")</code>
to search through the node for the named object.
It will return a reference to the named GraphObject if it is found, or <code>null</code> otherwise.
</p>
<p>
Using this, we could make an HTML button that changes the fill of the Shape inside of a selected Node:
</p>
<pre class="lang-js">
var selectionButton = document.getElementById("selectionButton");
selectionButton.addEventListener("click", function() {
myDiagram.commit(function(d) {
d.selection.each(function(node) {
var shape = node.findObject("SHAPE");
// If there was a GraphObject in the node named SHAPE, then set its fill to red:
if (shape !== null) {
shape.fill = "red";
}
});
}, "change color");
});</pre>
<!-- LIVE -->
<div id="myDiagramDiv4" class="diagramStyling" style="width:700px; height:150px"></div>
<button id="selectionButton">Select some Nodes; then click here to change Shape.fill inside selected Nodes</button>
<script>
var myDiagram = setupDiagram("myDiagramDiv4");
var selectionButton = document.getElementById("selectionButton");
selectionButton.addEventListener("click", function() {
myDiagram.commit(function(d) {
d.selection.each(function(node) {
var shape = node.findObject("SHAPE");
// If there was a GraphObject in the node named SHAPE, then set its fill to red:
if (shape !== null) {
shape.fill = "red";
}
});
}, "change color");
});
</script>
<h2 id="ChangingProperteisAndUpdatingModelUsingDataBindings">Changing Properties and Updating the Model using Data Bindings</h2>
<p>
Looking again at our Node template, we have the <code>Shape.fill</code>
property data-bound to the "color" property of our Node data:
</p>
<pre class="lang-js">
myDiagram.nodeTemplate =
$(go.Node, "Auto",
$(go.Shape, "Rectangle",
{ stroke: null, name: "SHAPE" },
new go.Binding("fill", "color")), // note this data binding
$(go.TextBlock,
{ margin: 6, font: "18px sans-serif" },
new go.Binding("text", "key"))
);</pre>
<p>
Changing the Shape's <code>fill</code> property inside our node will not,
as the Node template currently stands, update the model data.
</p>
<pre class="lang-js">
var node = myDiagram.findNodeForKey("Alpha");
var shape = node.findObject("SHAPE");
shape.fill = "red";
// outputs "lightblue" - the model has not changed!
console.log(node.data.color);</pre>
<p>
This is undesirable in some cases.
When we want the change to persist after saving and loading,
we will want the model data updated too.
</p>
<p>
However, in some situations this lack of persistence might be a good thing.
For instance if we want the color change for only cosmetic purposes,
such as changing the color of a button when hovering over it with the mouse,
we would not want to modify the model data that might be saved.
</p>
<p>
For now, suppose that we do want to update the model.
The preferred way to do this is to modify the data in the model
and depend on the data binding to automatically update the Shape.
However, we cannot modify the data directly by just setting the JavaScript property.
</p>
<pre class="lang-js" style="border: 6px solid red">
var node = myDiagram.findNodeForKey("Alpha");
// DO NOT DO THIS!
// This would update the data, but GoJS would not be notified
// that this arbitrary JavaScript object has been modified,
// and the associated Node will not be updated appropriately
node.data.color = "red";</pre>
<p>
Instead we should set the data property using the method
<code>Model.set(data, propertyName, propertyValue)</code>.
</p>
<pre class="lang-js" style="border: 6px solid lime">
var node = myDiagram.findNodeForKey("Alpha");
// Model.commit executes the given function within a transaction
myDiagram.model.commit(function(m) { // m == the Model
// This is the safe way to change model data.
// GoJS will be notified that the data has changed
// so that it can update the node in the Diagram
// and record the change in the UndoManager.
m.set(node.data, "color", "red");
}, "change color");
// outputs "red" - the model has changed!
console.log(node.data.color);
// and the user will see the red node</pre>
<div id="myDiagramDiv5" class="diagramStyling" style="width:700px; height:150px"></div>
<script>
var myDiagram = setupDiagram("myDiagramDiv5");
var node = myDiagram.findNodeForKey("Alpha");
// Model.commit executes the given function within a transaction
myDiagram.model.commit(function(m) { // m == the Model
// This is the safe way to change model data.
// GoJS will be notified that the data has changed
// so that it can update the node in the Diagram
// and record the change in the UndoManager.
m.set(node.data, "color", "red");
}, "change color");
</script>
<p>
Note that there is no longer any need to name the Shape "SHAPE",
because there is no longer any need to call <code>findObject</code> to look for the particular Shape.
Data binding will automatically update properties, so we do not have to do that ourselves.
</p>
<pre class="lang-js">
myDiagram.nodeTemplate =
$(go.Node, "Auto",
$(go.Shape, "Rectangle",
{ stroke: null }, // removed the name property
new go.Binding("fill", "color")),
$(go.TextBlock,
{ margin: 6, font: "18px sans-serif" },
new go.Binding("text", "key"))
);</pre>
<h2 id="SubjectMentionedAndFurtherReading">Subjects Mentioned and Further Reading</h2>
<ul>
<li>Data Binding — See the <a href="../intro/dataBinding.html">intro page on Data Binding for lots more detail</a>.</li>
<li>Transactions — See the <a href="../intro/transactions.html">intro page on Transactions</a>.</li>
<li>
<code>console.log</code> — A powerful debugging aid that is part of most browser's developer tools.
See the <a href="https://developers.google.com/chrome-developer-tools/docs/console">Chrome guide</a> or
the <a href="https://developer.mozilla.org/en-US/docs/Tools/Browser_Console">Firefox guide</a> for their respective developer consoles.
See more suggestions for debugging GoJS diagrams at the <a href="../intro/debugging.html">intro page on Debugging</a>.
</li>
</ul>
<p>
You may want to read more tutorials, such as the <a href="index.html">Learn GoJS</a> tutorial.
and the <a href="interactivity.html">Interactivity</a> tutorial.
You can also watch tutorials on <a href="https://www.youtube.com/channel/UC9We8EoX596-6XFjJDtZIDg">YouTube</a>.
</p>
<p>
If you are ready for a comprehensive overview of <b>GoJS</b>, have a look at the <a href="../intro/index.html">technical introduction</a>.
If you want to explore by example, have a look at <a href="../samples/index.html">the samples</a> to get a feel for what's possible with <b>GoJS</b>.
</p>
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