Files
ccvl/examples/hough.rs
T

59 lines
1.6 KiB
Rust

mod common;
use ccvl::*;
const LINE: image::SRGBA = image::SRGBA {
r: 1.0,
g: 0.0,
b: 0.0,
a: 1.0,
};
fn main() -> std::process::ExitCode {
common::process_image(|mut img| {
let greyscale = img.map(|p| image::Luminance::from(p));
let edges = filter::canny(greyscale);
for line in hough::lines(10.0, edges) {
let ((x0, y0), (x1, y1)) = endpoints(line, img.extent);
draw::line(x0, y0, x1, y1, &mut img, LINE);
}
img
})
}
fn endpoints(
l: hough::Line,
lim: image::Extent,
) -> ((usize, usize), (usize, usize)) {
if l.theta.abs() < 1e-3 {
((l.rho as usize, 0), (l.rho as usize, lim.y - 1))
} else if l.theta - std::f32::consts::PI / 2.0 < 1e-3 {
((0, l.rho as usize), (lim.x - 1, l.rho as usize))
} else {
let w = lim.x as f32 - 1e-3;
let h = lim.y as f32 - 1e-3;
let ros = l.rho / l.theta.sin();
let roc = l.rho / l.theta.cos();
let t = l.theta.tan();
let candidates: [(f32, f32); 4] =
[(roc - h * t, h), (0.0, ros), (roc, 0.0), (w, ros - w / t)];
let res = candidates
.into_iter()
.filter(|p| in_bounds(p, lim))
.map(|(x, y)| (x as usize, y as usize))
.collect::<Vec<_>>();
if res.len() != 2 {
panic!("Unexpected number of endpoints for {:?}", l);
}
(res[0], res[1])
}
}
fn in_bounds(q: &(f32, f32), lim: image::Extent) -> bool {
let x_in = 0.0 <= q.0 && q.0 < lim.x as f32;
let y_in = 0.0 <= q.1 && q.1 < lim.y as f32;
x_in && y_in
}