Class pv.Layout.Pack

Extends pv.Layout.Hierarchy.
Implements a hierarchical layout using circle-packing. The meaning of the exported mark prototypes changes slightly in the space-filling implementation:

node - for rendering nodes; typically a pv.Dot.
link - unsupported; undefined. Links are encoded implicitly in the arrangement of the space-filling nodes.
label - for rendering node labels; typically a pv.Label.

The pack layout support dynamic sizing for leaf nodes, if a #size psuedo-property is specified. The default size function returns 1, causing all leaf nodes to be sized equally, and all internal nodes to be sized by the number of leaf nodes they have as descendants.

The size function can be used in conjunction with the order property, which allows the nodes to the sorted by the computed size. Note: for sorting based on other data attributes, simply use the default null for the order property, and sort the nodes beforehand using the pv.Dom operator.

For more details on how to use this layout, see pv.Layout.Hierarchy.
Defined in: Pack.js.

Class Summary
Constructor Attributes	Constructor Name and Description
	pv.Layout.Pack() Constructs a new, empty circle-packing layout.

Field Summary
Field Attributes	Field Name and Description
	defaults Default properties for circle-packing layouts.
	order The sibling node order.
	spacing The spacing parameter; defaults to 1, which provides a little bit of padding between sibling nodes and the enclosing circle.

Fields borrowed from class pv.Layout.Network:: label, link, node
Fields borrowed from class pv.Panel:: canvas, children, overflow, transform
Fields borrowed from class pv.Bar:: fillStyle, height, lineWidth, strokeStyle, width
Fields borrowed from class pv.Mark:: bottom, childIndex, cursor, data, events, index, left, parent, proto, reverse, right, root, scale, title, top, type, visible

Method Summary
Method Attributes	Method Name and Description
	size(f) Specifies the sizing function.

Methods borrowed from class pv.Layout.Network:: reset
Methods borrowed from class pv.Panel:: add, anchor
Methods borrowed from class pv.Mark:: anchorTarget, def, event, extend, margin, mouse, render

Class Detail

pv.Layout.Pack()

Constructs a new, empty circle-packing layout. Layouts are not typically constructed directly; instead, they are added to an existing panel via pv.Mark#add.

See:: "Visualization of large hierarchical data by circle packing" by W. Wang, H. Wang, G. Dai, and H. Wang, ACM CHI 2006.

Field Detail

{pv.Layout.Pack} defaults

Default properties for circle-packing layouts. The default spacing parameter is 1 and the default order is "ascending".

{string} order

The sibling node order. The default order is null, which means to use the sibling order specified by the nodes property as-is. A value of "ascending" will sort siblings in ascending order of size, while "descending" will do the reverse. For sorting based on data attributes other than size, use the default null for the order property, and sort the nodes beforehand using the pv.Dom operator.

See:: pv.Dom.Node#sort

{number} spacing

The spacing parameter; defaults to 1, which provides a little bit of padding between sibling nodes and the enclosing circle. Larger values increase the spacing, by making the sibling nodes smaller; a value of zero makes the leaf nodes as large as possible, with no padding on enclosing circles.

Method Detail

{pv.Layout.Pack} size(f)

Specifies the sizing function. By default, a sizing function is disabled and all nodes are given constant size. The sizing function is invoked for each leaf node in the tree (passed to the constructor).

For example, if the tree data structure represents a file system, with files as leaf nodes, and each file has a bytes attribute, you can specify a size function as:

    .size(function(d) d.bytes)

As with other properties, a size function may specify additional arguments to access the data associated with the layout and any enclosing panels.

Parameters:
{function} f: the new sizing function.

Returns:: {pv.Layout.Pack} this.

Classes

Class pv.Layout.Pack