Awesome
Treemap
Implements the Squarified Treemap algorithm published by Mark Bruls, Kees Huizing, and Jarke J. van Wijk.
The Squarified Treemap algorithm paper can be found here: https://www.win.tue.nl/~vanwijk/stm.pdf
Uses
Suppose we have a rectangle with a width of 6 and a height of 4, and furthermore suppose that this rectangle must be subdivided in seven rectangles with areas 6, 6, 4, 3, 2, 2, and 1. The standard treemap algorithm uses a simple approach: The rectangle is subdivided either horizontally or vertically. Thin rectangles emerge, with aspect ratios of 16 and 36, respectively.
In other words, it'll look something like this:
+------+------+----+---+--+-+
| | | | | | |
| | | | | | |
| 6 | 6 | 4 | 3 | 2|1|
| | | | | | |
+------+------+----+---+--+-+
The Squarified Treemap algorithm tesselates a rectangle recursively into rectangles, such that their aspect ratios approach 1 as close as possible.
+-------------+-----+-----+--+
| | 2 | 2 | 1|
| 6 +-----+-+---+--|
|-------------+ | |
| | | |
| 6 | 4 | 3 |
+-------------+-------+------+
This can be useful for a variety of purposes:
- visualizing hierarchal structures, such as showing how much space each directory uses in a file drive
- generating a floor map given an area on how each room should be subdivided (bathrooms would need a smaller amount of space than a living room, for example)
Example
This example will tesselate a rectangle with a width of 6 and a height of 4 with seven rectangles with areas 6, 6, 4, 3, 2, 2, and 1, then display each rectangle's top-left corner's x and y position within the larger rectangle (the bounds), as well as their respective height and width.
To start, generate a new project:
$ cargo new --bin treemap-example
Created binary (application) `treemap-example` package
Add treemap
to Cargo.toml:
[dependencies]
treemap = "0.3"
Then, in src/main.rs
:
use treemap::{MapItem, Mappable, Rect, TreemapLayout};
fn main() {
let layout = TreemapLayout::new();
let bounds = Rect::from_points(0.0, 0.0, 6.0, 4.0);
let mut items: Vec<Box<dyn Mappable>> = vec![
Box::new(MapItem::with_size(6.0)),
Box::new(MapItem::with_size(6.0)),
Box::new(MapItem::with_size(4.0)),
Box::new(MapItem::with_size(3.0)),
Box::new(MapItem::with_size(2.0)),
Box::new(MapItem::with_size(2.0)),
Box::new(MapItem::with_size(1.0)),
];
layout.layout_items(&mut items, bounds);
for item in items {
let item_bounds = item.bounds();
println!("x={} y={} w={} h={}", item_bounds.x, item_bounds.y, item_bounds.w, item_bounds.h);
println!("------");
}
}