Here’s the updated code for the samples/swimbands.html sample:
[code] // this controls whether the layout is horizontal and the layer bands are vertical, or vice-versa:
var HORIZONTAL = true; // this constant parameter can only be set here, not dynamically
// Perform a TreeLayout where commitLayers is overridden to modify the background Part whose key is “_BANDS”.
function LayeredTreeLayout() {
go.TreeLayout.call(this);
this.layerStyle = go.TreeLayout.LayerUniform; // needed for straight layers
}
go.Diagram.inherit(LayeredTreeLayout, go.TreeLayout);
LayeredTreeLayout.prototype.commitLayers = function(layerRects, offset) {
// update the background object holding the visual “bands”
var bands = this.diagram.findPartForKey("_BANDS");
if (bands) {
var model = this.diagram.model;
bands.location = this.arrangementOrigin.copy().add(offset);
// make each band visible or not, depending on whether there is a layer for it;
// if visible, set the sizes of particular objects in each band
for (var it = bands.elements; it.next(); ) {
var idx = it.key;
var elt = it.value; // the item panel representing a band
if (idx < layerRects.length) {
elt.visible = true;
var r = layerRects[idx];
elt.position = r.position;
// limit the header text width
var tb = elt.findObject(“TEXTBLOCK”);
if (tb) tb.width = HORIZONTAL ? r.width : r.height;
// option 1: rectangular bands:
var sh = elt.findObject(“SHAPE”);
if (sh) sh.desiredSize = r.size;
// option 2: separator lines:
var ln = elt.findObject(“LINE”);
if (ln) {
if (HORIZONTAL) {
ln.height = r.height;
} else {
ln.width = r.width;
}
}
} else {
elt.visible = false;
}
}
}
};
// end LayeredTreeLayout
function init() {
if (window.goSamples) goSamples(); // init for these samples – you don’t need to call this
var $ = go.GraphObject.make;
myDiagram = $(go.Diagram, “myDiagram”,
{
initialContentAlignment: go.Spot.Center,
layout: $(LayeredTreeLayout, // custom layout is defined above
{
angle: HORIZONTAL ? 0 : 90,
arrangement: HORIZONTAL ? go.TreeLayout.ArrangementVertical : go.TreeLayout.ArrangementHorizontal
}),
“undoManager.isEnabled”: true
});
myDiagram.nodeTemplate =
$(go.Node, go.Panel.Auto,
$(go.Shape, "Rectangle",
{ fill: "white" }),
$(go.TextBlock, { margin: 5 },
new go.Binding("text", "key")));
// There should be at most a single object of this category.
// This Part will be modified by LayeredTreeLayout.commitLayers to display visual "bands"
// where each "layer" is a layer of the tree.
// This template is parameterized at load time by the HORIZONTAL parameter.
// You also have the option of showing rectangles for the layer bands or
// of showing separator lines between the layers, but not both at the same time,
// by commenting in/out the indicated code.
myDiagram.nodeTemplateMap.add("Bands",
$(go.Part, "Position",
new go.Binding("itemArray"),
{
isLayoutPositioned: false, // but still in document bounds
locationSpot: new go.Spot(0, 0, HORIZONTAL ? 0 : 16, HORIZONTAL ? 16 : 0), // account for header height
layerName: "Background",
pickable: false,
selectable: false,
itemTemplate:
$(go.Panel, HORIZONTAL ? "Vertical" : "Horizontal",
$(go.TextBlock,
{
name: "TEXTBLOCK",
angle: HORIZONTAL ? 0 : 270,
textAlign: "center",
wrap: go.TextBlock.None,
font: "bold 11pt sans-serif",
background: $(go.Brush, go.Brush.Linear, { 0: "lightgray", 1: "whitesmoke" })
},
new go.Binding("text")
),
// option 1: rectangular bands:
$(go.Shape,
{ name: "SHAPE", stroke: null, strokeWidth: 0 },
new go.Binding("fill", "itemIndex", function(i) { return i % 2 == 0 ? "white" : "lightgray"; }).ofObject())
// option 2: separator lines:
//(HORIZONTAL
// ? $(go.Shape, "LineV",
// { name: "LINE", stroke: "gray", alignment: go.Spot.TopLeft, width: 1 },
// new go.Binding("visible", "itemIndex", function(i) { return i > 0; }).ofObject())
// : $(go.Shape, "LineH",
// { name: "LINE", stroke: "gray", alignment: go.Spot.TopLeft, height: 1 },
// new go.Binding("visible", "itemIndex", function(i) { return i > 0; }).ofObject())
//)
)
}
));
myDiagram.linkTemplate =
$(go.Link,
$(go.Shape)); // simple black line, no arrowhead needed
// define the tree node data
var nodearray = [
{ // this is the information needed for the headers of the bands
key: "_BANDS",
category: "Bands",
itemArray: [
{ text: "Zero" },
{ text: "One" },
{ text: "Two" },
{ text: "Three" },
{ text: "Four" },
{ text: "Five" }
]
},
// these are the regular nodes in the TreeModel
{ key: "root" },
{ key: "oneB", parent: "root" },
{ key: "twoA", parent: "oneB" },
{ key: "twoC", parent: "root" },
{ key: "threeC", parent: "twoC" },
{ key: "threeD", parent: "twoC" },
{ key: "fourB", parent: "threeD" },
{ key: "fourC", parent: "twoC" },
{ key: "fourD", parent: "fourB" },
{ key: "twoD", parent: "root" }
];
myDiagram.model = new go.TreeModel(nodearray);
}[/code]
