Rappid - layout

ForceDirected plugin implements automatic layouts for graphs using a force-directed approach. This is useful for, usually larger, undirected graphs.

Installation

Include the joint.layout.ForceDirected.js file into your HTML:

<script src="joint.layout.ForceDirected.js"></script>

Usage

ForceDirected layout plugin auto-layouts graphs based on three forces: repulsive force (forces nodes to move out of each other), attractive force (tries to get nodes together like a spring) and a gravity force (tendency of the nodes to move to a certain point).

The ForceDirected constructor accepts a couple of parameters for configuring the layout. The gravityCenter parameter is the point the nodes tend to move to. This is usually set to the center of the area where the nodes are to be laid out. charge parameter affects the repulsive force. Bigger the parameter is, bigger the repulsive force. linkDistance and linkStrength both affect the attractive force (you can think of it as parameters of a spring that tights together two nodes). Bigger the linkStrength, bigger the attractive force between two connected nodes. On the other hand, smaller the linkDistance, shorter links you allow and so the attractive force is bigger between two connected nodes.

There is no one-fits-all set of parameters that would give great result for all possible graphs. Therefore, it is suggested that you to play with the parameters, try to set different values so that it gives a good result for your use case.

var graphLayout = new joint.layout.ForceDirected({
    graph: graph // or array of selected cells
    x: 0,
    y: 0,
    width: 600,
    height: 400,
    gravityCenter: { x: 300, y: 200 },
    charge: 180,
    linkDistance: 30
});

graphLayout.start();

Array.from({ length: 100 }).forEach(function() { graphLayout.step(); });

Note: It is recommended to use the requestAnimationFrame for stepping the layout.

GridLayout implements automatic layouts for graphs. This is useful in many scenarios, one of them being e.g. automatically positioning elements in Stencil.

Installation

Include the joint.layout.GridLayout.js file into your HTML:

<script src="joint.layout.GridLayout.js"></script>

Usage

GridLayout plugin exposes one function joint.layout.GridLayout.layout(graphOrElements, options). The first parameter graphOrElements is the joint.dia.Graph or an array of joint.dia.Elements we want to layout. The second parameter options is an object that contains various options for configuring the layout.

graph.addCells([
  new joint.shapes.basic.Rect({ size: { width: 80, height: 50 }}),
  new joint.shapes.basic.Rect({ size: { width: 50, height: 50 }}),
  new joint.shapes.basic.Circle({ size: { width: 80, height: 50 }}),
  new joint.shapes.basic.Circle({ size: { width: 50, height: 50 }})
]);

// Layout the entire graph
joint.layout.GridLayout.layout(graph, {
  columns: 2,
  columnWidth: 100,
  rowHeight: 70
});

// Layout the circles with minimal resulting `y` coordinate equals 100.
var circles = graph.getElements().filter(function(el) {
    return el instanceof joint.shapes.basic.Circle;
});
joint.layout.GridLayout.layout(circles, {
    columns: 2,
    marginY: 100
});

Here are the options for configuring the GridLayout:

• columns - Number of columns. It defaults to 1.
• columnWidth
  • 'auto' - width of a column is equal to the widest element amongst all elements
  • 'compact' - width of a column is equal to the widest element in the column
  • number - value of a column width (e.g. 200)
  It defaults to 'auto'.
• rowHeight
  • 'auto' - height of a row is equal to the highest element amongst all elements
  • 'compact' - height of a row is equal to the highest element in the row
  • number - value of a row height (e.g. 100)
  It defaults to 'auto'.
• dx - Shifts the elements horizontally by a given amount. It defaults to 0.
• dy - Shifts the elements vertically by a given amount. It defaults to 0.
• centre - Positions the elements in the centre of a grid cell. It defaults to true.
• resizeToFit - Resizes the elements to fit a grid cell, preserving the aspect ratio (default: false)
• marginX - Sets the origin (x coordinate) of the most top-left element. It defaults to 0.
• marginY - Sets the origin (y coordinate) of the most top-left element. It defaults to 0.
• deep - Uses deep positioning for elements when set to true. i.e. moves not only the elements but also their descendants. It defaults to false.
• parentRelative - Position the elements relatively to their parents.

  var padding = 20;
  // layout the children of the element `el`
  joint.layout.GridLayout.layout(el.getEmbeddedCells(), {
    parentRelative: true,
    marginX: padding,
    marginY: padding
  });
  // resize the element `el` to fit all children
  el.fitEmbeds({ padding: padding });
  

layout.TreeLayout is a layout algorithm for tree-like graphs. It's great for displaying org charts, mind maps, class hierarchies and other tree structures. The layout.TreeLayout is strong in combination with the ui.TreeLayoutView which implements drag&drop functionality useful when editing a tree structure.

Installation

Include joint.layout.treeLayout.js file to your HTML:

<script src="joint.layout.treeLayout.js"></script>

Usage

Create an object of layout.TreeLayout type passing your graph (object of type joint.dia.Graph) as a parameter. Then you can just call the layout() method and the graph will be automatically laid out. It's important to note that the position of the root element of the tree will stay the same as it was before the layout. This allows you to move the tree to a position you want or have your tree be laid out around the root.

var graphLayout = new joint.layout.TreeLayout({
    graph: graph,
    parentGap: 20,
    siblingGap: 20
});

// Root element position stays the same after the layout.
// In this demo, we assume the root is the first element.
var root = graph.getElements()[0].position(200, 200);

graphLayout.layout();

Configuration

The following table lists options that you can pass to the layout.TreeLayout constructor function:

// e.g. a collapse branch is not visible in the paper but resides in the graph.
function(children) {
    return children.filter(function(child) {
        return child.get('visible');
    });
}

element.transition('position', position, {
    delay: 300,
    valueFunction: joint.util.interpolate.object,
});

The tree layout also reads some element properties allowing for a fine control of the layout engine. These are:

element.set({
    direction: 'R',
    size: { width: 100, height: 100 },
    margin: 20
});
// as the `element` siblings are located above and under the element,
// it will in fact occupied an area of { width: 100, height: 140 }

API