## Nodes

You can customize your nodes to have exactly the appearance and behavior that you want. So far you have only seen very simple nodes. But if you have seen the Sample Applications, you have seen many other kinds of nodes.

In this page we demonstrate some of the choices you can make when designing your nodes.

### Surrounding Content

It is common to surround interesting information with a border or other background.

#### Simple borders

Many of the simplest nodes just consist of a Panel of type Panel.Auto with a Shape surrounding a TextBlock.

      diagram.nodeTemplate =
        $(go.Node, "Auto",
          $(go.Shape, "Rectangle",
            new go.Binding("fill", "color")),
          $(go.TextBlock,
            { margin: 5 },
            new go.Binding("text", "key"))
        );

      diagram.model.nodeDataArray = [
        { key: "Alpha", color: "lightblue" }
      ];

#### Shaped nodes

The Shape surrounding the content need not be rectangular. This example demonstrates a number of shapes.

      diagram.nodeTemplate =
        $(go.Node, "Auto",
          $(go.Shape,
            new go.Binding("figure", "fig"),
            new go.Binding("fill", "color")),
          $(go.TextBlock,
            { margin: 5 },
            new go.Binding("text", "key"))
        );

      diagram.model.nodeDataArray = [
        { key: "Alpha", color: "lightblue", fig: "RoundedRectangle" },
        { key: "Beta", color: "lightblue", fig: "Ellipse" },
        { key: "Gamma", color: "lightblue", fig: "Hexagon" },
        { key: "Delta", color: "lightblue", fig: "FramedRectangle" },
        { key: "Epsilon", color: "lightblue", fig: "Cloud" },
        { key: "Zeta", color: "lightblue", fig: "Procedure" }
      ];

The surrounding/background object need not be a Shape. You could use a Picture or even a more complex object such as a Panel.

#### Complex contents

The content of an Auto Panel need not be limited to a single TextBlock -- you can have arbitrarily complex panels of objects. In this example the content is a Table Panel with three rows of TextBlocks.

      diagram.nodeTemplate =
        $(go.Node, "Auto",
          $(go.Shape,
            { fill: $(go.Brush, "Linear", { 0: "white", 1: "lightblue" }),
              stroke: "darkblue", strokeWidth: 2 }),
          $(go.Panel, "Table",
            { defaultAlignment: go.Spot.Left, margin: 4 },
            $(go.RowColumnDefinition, { column: 1, width: 4 }),
            $(go.TextBlock,
              { row: 0, column: 0, columnSpan: 3, alignment: go.Spot.Center },
              { font: "bold 12pt sans-serif" },
              new go.Binding("text", "key")),
            $(go.TextBlock, "First: ",
              { row: 1, column: 0 }),
            $(go.TextBlock,
              { row: 1, column: 2 },
              new go.Binding("text", "prop1")),
            $(go.TextBlock, "Second: ",
              { row: 2, column: 0 }),
            $(go.TextBlock,
              { row: 2, column: 2 },
              new go.Binding("text", "prop2"))
          )
        );

      diagram.model.nodeDataArray = [
        { key: "Alpha", prop1: "value of 'prop1'", prop2: "the other property" }
      ];

#### Fixed-size nodes

The above examples have the "Auto" Panel surround some content, where the content might be of different sizes. That results in the Nodes having different sizes.

If you want a Panel (and thus a Node, because Node inherits from Part which inherits from Panel) to be of fixed size, set GraphObject.desiredSize on that panel. (Equivalently, you can set GraphObject.width and GraphObject.height.) That may result in the clipping of content that is too large, or it may result in extra space if the content is smaller than the available area provided by the "Auto" Panel.

      diagram.nodeTemplate =
        $(go.Node, "Auto",
          { desiredSize: new go.Size(100, 50) },  // on Panel
          $(go.Shape,
            new go.Binding("figure", "fig"),
            new go.Binding("fill", "color")),
          $(go.TextBlock,
            { margin: 5 },
            new go.Binding("text", "key"))
        );
      diagram.model.nodeDataArray = [
        { key: "Alpha", color: "lightblue", fig: "RoundedRectangle" },
        { key: "Beta", color: "lightblue", fig: "Ellipse" },
        { key: "Gamma", color: "lightblue", fig: "Hexagon" },
        { key: "Delta", color: "lightblue", fig: "FramedRectangle" },
        { key: "Epsilon,Epsilon,Epsilon", color: "lightblue", fig: "Cloud" },
        { key: "Z", color: "lightblue", fig: "Procedure" }
      ];

Note how the "Epsilon..." TextBlock is measured with the constraint of having a limited width, as imposed by the Panel's width. That results in the text being wrapped before (maybe) being clipped.

You probably do not want to set the desiredSize of the main element, the Shape in this case above. If you did, that would not constrain how the content elements are sized within the Panel.

      diagram.nodeTemplate =
        $(go.Node, "Auto",
          $(go.Shape,
            { desiredSize: new go.Size(100, 50) },  // on main element, not on Panel
            new go.Binding("figure", "fig"),
            new go.Binding("fill", "color")),
          $(go.TextBlock,
            { margin: 5 },
            new go.Binding("text", "key"))
        );
      diagram.model.nodeDataArray = [
        { key: "Alpha", color: "lightblue", fig: "RoundedRectangle" },
        { key: "Beta", color: "lightblue", fig: "Ellipse" },
        { key: "Gamma", color: "lightblue", fig: "Hexagon" },
        { key: "Delta", color: "lightblue", fig: "FramedRectangle" },
        { key: "Epsilon,Epsilon,Epsilon", color: "lightblue", fig: "Cloud" },
        { key: "Z", color: "lightblue", fig: "Procedure" }
      ];

Note how the TextBlock is measured without the constraint of having a limited width from the Panel. That results in the text being treated as a single long line, which is then clipped by the Panel.

### Stacked Content

Many simple nodes consist of a few objects positioned above each other or next to each other.

#### Icons

Perhaps the most commonly seen kind of node can be implemented using a Vertical Panel.

      diagram.nodeTemplate =
        $(go.Node, "Vertical",
          $(go.Picture,
            { maxSize: new go.Size(50, 50) },
            new go.Binding("source", "img")),
          $(go.TextBlock,
            { margin: new go.Margin(3, 0, 0, 0),
              maxSize: new go.Size(100, 30),
              isMultiline: false },
            new go.Binding("text", "text"))
        );

      diagram.model.nodeDataArray = [
        { text: "kitten", img: "images/50x40.png" }
      ];

Of course you are not limited to just two objects in a panel. In fact you can have as many GraphObjects in a "Vertical" or a "Horizontal" Panel as you like.

      diagram.nodeTemplate =
        $(go.Node, "Vertical",
          $(go.TextBlock,
            { margin: new go.Margin(3, 0, 0, 0),
              maxSize: new go.Size(100, 30),
              isMultiline: false,
              font: "bold 10pt sans-serif" },
            new go.Binding("text", "head")),
          $(go.Picture,
            { maxSize: new go.Size(50, 50) },
            new go.Binding("source", "img")),
          $(go.TextBlock,
            { margin: new go.Margin(3, 0, 0, 0),
              maxSize: new go.Size(100, 30),
              isMultiline: false },
            new go.Binding("text", "foot"))
        );
      diagram.model.nodeDataArray = [
        { head: "Kitten", foot: "Tantomile", img: "images/50x40.png" }
      ];

#### Small icons

Another commonly seen kind of node can be implemented using a Horizontal Panel.

      diagram.nodeTemplate =
        $(go.Node, "Horizontal",
          $(go.Picture,
            { maxSize: new go.Size(16, 16) },
            new go.Binding("source", "img")),
          $(go.TextBlock,
            { margin: new go.Margin(0, 0, 0, 2) },
            new go.Binding("text", "text"))
        );

      diagram.model.nodeDataArray = [
        { text: "kitten", img: "images/50x40.png" }
      ];

### Decorated Content

Sometimes you want to have a simple node that may display additional visuals to indicate what state it is in.

One way to implement this is to use a Spot Panel, where the main element is itself a Panel containing the elements that you always want to display, and there are additional objects located at spots around the main element.

      diagram.nodeTemplate =
        $(go.Node, "Spot",
          // the main content:
          $(go.Panel, "Vertical",
            $(go.Picture,
              { maxSize: new go.Size(50, 50) },
              new go.Binding("source", "img")),
            $(go.TextBlock,
              { margin: new go.Margin(3, 0, 0, 0) },
              new go.Binding("text", "text"),
              new go.Binding("stroke", "error", function(err) { return err ? "red" : "black" }))
          ),
          // decorations:
          $(go.Shape, "TriangleUp",
            { alignment: go.Spot.TopLeft,
              fill: "yellow", width: 14, height: 14,
              visible: false },
            new go.Binding("visible", "info", function(i) { return i ? true : false; })),
          $(go.Shape, "StopSign",
            { alignment: go.Spot.TopRight,
              fill: "red", width: 14, height: 14,
              visible: false },
            new go.Binding("visible", "error")),
          {
            toolTip:
              $(go.Adornment, "Auto",
                $(go.Shape, { fill: "#FFFFCC" },
                  new go.Binding("visible", "info", function(i) { return i ? true : false; })),
                $(go.TextBlock, { margin: 4 },
                  new go.Binding("text", "info"))
              )
          }
        );

      diagram.model.nodeDataArray = [
        { text: "kitten", img: "images/50x40.png", info: "" },
        { text: "kitten", img: "images/50x40.png", error: true, info: "shredded curtains" }
      ];

As another example of a node decoration, this implements a "ribbon" at the top right corner of the node. The ribbon is implemented by a Panel that contains both a Shape and a TextBlock, and the panel is positioned by its GraphObject.alignment and GraphObject.alignmentFocus in the Spot Panel that also is the Node. The appearance of the ribbon is achieved by using a custom Geometry and binding GraphObject.opacity.

      diagram.nodeTemplate =
        $(go.Node, "Spot",
          { locationSpot: go.Spot.Center, locationObjectName: "BODY" },
          { selectionObjectName: "BODY" },
          $(go.Panel, "Auto",
            { name: "BODY", width: 150, height: 100 },
            { portId: "" },
            $(go.Shape,
              { fill: "lightgray", stroke: null, strokeWidth: 0 }),
            $(go.TextBlock,
              new go.Binding("text"))
          ),
          $(go.Panel, "Spot",
            new go.Binding("opacity", "ribbon", function(t) { return t ? 1 : 0; }),
            // note that the opacity defaults to zero (not visible),
            // in case there is no "ribbon" property
            { opacity: 0,
              alignment: new go.Spot(1, 0, 5, -5),
              alignmentFocus: go.Spot.TopRight },
            $(go.Shape,  // the ribbon itself
              { geometryString: "F1 M0 0 L30 0 70 40 70 70z",
                fill: "red", stroke: null, strokeWidth: 0 }),
            $(go.TextBlock,
              new go.Binding("text", "ribbon"),
              { alignment: new go.Spot(1, 0, -29, 29),
                angle: 45, maxSize: new go.Size(100, NaN),
                stroke: "white", font: "bold 13px sans-serif", textAlign: "center" })
          )
        );

      diagram.model = new go.GraphLinksModel([
        { key: 1, text: "Alpha" },
        { key: 2, text: "Beta", ribbon: "NEWEST" }
      ],[
      ]);