The pixel_map Rust Crate

A PixelMap stores pixel data for an image in a quadtree structure.

Overview

A PixelMap is an MX quadtree implementation, occupies a region of two-dimensional space at the root node, and subdivides down to the pixel level. A type-generic pixel data value can be stored for each pixel in the map, but the tree structure optimizes storage for regions of common values. A pixel value must be Copy + PartialEq.

Project status: alpha. Releases may contain breaking changes.

Usage

Installation

Add the crate to your Cargo.toml:

cargo add pixel_map

Creating a Pixel Map

use pixel_map::PixelMap;

// Example pixel data
struct Color(u8, u8, u8);

fn main() {
    let mut pixel_map = PixelMap::<Color>::new(
        &uvec2(1920, 1080), // size of the pixel map
        Color(0, 0, 0),     // initial value
        1,                  // pixel size
    );
}

Drawing on the PixelMap

fn main() {
    let pixel_map = ...;

    // Set a pixel
    pixel_map.set_pixel((11, 12), Color(255, 0, 0));

    // Draw a line
    pixel_map.draw_line(&ULine::new((500, 500), (600, 400)), Color(0, 255, 0));

    // Draw a rectangle
    pixel_map.draw_rect(&URect::from_corners(uvec2(200, 200), uvec2(300, 300)), Color(0, 0, 255));

    // Draw a circle
    pixel_map.draw_circle(&ICircle::new((500, 500), 100), Color(0, 0, 255));
}

Navigating the PixelMap

fn main() {
    let pixel_map = ...;

    // Visit all leaf nodes
    pixel_map.visit(|node| {
        println!("region: {:?}, value: {:?}", node.region(), node.value());
    });

    // Visit all leaf nodes that have been modified
    pixel_map.visit_dirty(|node| {
        println!("region: {:?}, value: {:?}", node.region(), node.value());
    });
    pixel_map.clear_dirty(true /*recurse*/);
}

Features

• Set individual pixel values, or draw primitive shapes:
  • Lines
  • Rectangles
  • Circles
• Perform boolean operations against two pixel maps (i.e. union, intersection, difference, xor).
• Detect changes to tree nodes via a "dirty" flag.
• Calculate contiguous contouring lines around shapes.

Limitations

• Loading and saving pixel data into various image formats is outside the scope of this crate. But, the basic operations necessary to both populate pixel data, and traverse the quadtree structure are provided. So, this is achievable in encompassing or accompanying code, according to the needs of your use case.

Testing

Run cargo test to unit test.

Mind blown, hey?

Benchmarking

Run cargo bench to run all Criterion benchmarks. Or, cargo bench --bench <name> to run a particular benchmark.

Benchmarks are integrated with pprof to produce flamegraphs, upon activation.

Run cargo benchmark --bench <name> -- --profile-time=5 to sample the benchmark run, and generate a flamegraph, which can be found in ./target/criterion/<name>/<group>/profile/flamegraph.svg.

License

pixel_map is free and open source. All code in this repository is dual-licensed under either of the following, at your option:

• MIT License (LICENSE-MIT or http://opensource.org/licenses/MIT)
• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)