Modify contour finding to return path vertices instead of trace

examples/contours.rs

@@ -21,12 +21,15 @@ fn main() -> std::process::ExitCode {
 		let thresholded = filter::threshold_auto(greyscale);
         let contours = contour::find(thresholded);
         for contour in contours {
-            for (x, y) in contour.trace {
-                *img.at_mut(x, y) = match contour.kind {
-                    contour::Kind::Inner => INNER,
-                    contour::Kind::Outer => OUTER,
-                };
-            }
+			let n = contour.vertices.len();
+			for i in 0..n {
+				let (x0, y0) = contour.vertices[i];
+				let (x1, y1) = contour.vertices[(i + 1) % n];
+				draw::line(x0, y0, x1, y1, &mut img, match contour.kind {
+					contour::Kind::Outer => OUTER,
+					contour::Kind::Inner => INNER,
+				});
+			}
         }
         img
     })