# [−][src]Crate marching_squares

This crate provides an (optionally parallelizable) marching squares algorithm to generate isolines from a heightmap of `Vec<Vec<i16>>` values.

# Warning

• The returned lines may only have two points.

# Example

```use marching_squares::{Field, Point};

fn main() {

let width = 1600_usize;
let height = 1600_usize;

let n_steps = 10_usize;
let mut min_val = 0;
let mut max_val = 0;

// Build the heightmap data (here: randomly generated from a function)
let z_values = (0..height).map(|y| {
(0..width).map(|x| {
let x = (x as f64 - width as f64 / 2.0) / 150.0;
let y = (y as f64 - height as f64 / 2.0) / 150.0;
let val = ((1.3 * x).sin() * (0.9 * y).cos() + (0.8 * x).cos() * (1.9 * y).sin() + (y * 0.2 * x).cos()) as i16;
min_val = min_val.min(val);
max_val = max_val.max(val);
val
}).collect()
}).collect::<Vec<Vec<i16>>>();

let field = Field {
dimensions: (width, height),
top_left: Point { x: 0.0, y: 0.0 },
pixel_size: (1.0, 1.0),
values: &z_values,
};

let step_size = (max_val - min_val) as f32 / n_steps as f32;

// Generate 10 isolines
// note: you could do this in parallel using rayon
for step in 0..n_steps {
let isoline_height = min_val as f32 + (step_size * step as f32);
println!("{:#?}", field.get_contours(isoline_height as i16));
}
}```

## Structs

 Field Raster heightmap field containing the z-values of each pixel Line Line containing a `Vec` Point 2-dimensional Point (x, y)