README.markdown
1 # webtreemap
2
3 A simple treemap implementation using web technologies (DOM nodes, CSS
4 styling and transitions) rather than a big canvas/svg/plugin.
5
6 Play with a [demo][].
7
8 [demo]: http://martine.github.com/webtreemap/demo/demo.html
9
10 ## Creating your own
11
12 1. Create a page with a DOM node (i.e. a `<div>`) that will contain
13 your treemap.
14 2. Add the treemap to the node via something like
15
16 appendTreemap(document.getElementById('mynode'), mydata);
17 3. Style the treemap using CSS.
18
19 ### Input format
20
21 The input data (`mydata` in the overview snippet) is a tree of nodes,
22 likely imported via a separate JSON file. Each node (including the
23 root) should contain data in the following format.
24
25 {
26 name: (HTML that is displayed via .innerHTML on the caption),
27 data: {
28 "$area": (a number, in arbitrary units)
29 },
30 children: (list of child tree nodes)
31 }
32
33 (This strange format for data comes from the the [JavaScript InfoVis
34 Toolkit][thejit]. I might change it in the future.)
35
36 The `$area` of a node should be the sum of the `$area` of all of its
37 `children`.
38
39 (At runtime, tree nodes will dynamically will gain two extra
40 attributes, `parent` and `dom`; this is only worth pointing out so
41 that you don't accidentally conflict with them.)
42
43 ### CSS styling
44
45 The treemap is constructed with one `div` per region with a separate
46 `div` for the caption. Each div is styleable via the
47 `webtreemap-node` CSS class. The captions are stylable as
48 `webtreemap-caption`.
49
50 Each level of the tree also gets a per-level CSS class,
51 `webtreemap-level0` through `webtreemap-level4`. These can be
52 adjusted to e.g. made different levels different colors. To control
53 the caption on a per-level basis, use a CSS selector like
54 `.webtreemap-level2 > .webtreemap-caption`.
55
56 Your best bet is to modify the included `webtreemap.css`, which
57 contains comments about required and optional CSS attributes.
58
59 ## Related projects
60
61 * [JavaScript InfoVis Toolkit][thejit]
62
63 [thejit]: http://thejit.org/
64