chore: Add example to create mask and use set_mouse_callback

Author: gfgafn

examples/create_mask.rs

@@ -0,0 +1,178 @@
+//! # Create Mask
+//! Reference: [opencv/samples/cpp/create_mask.cpp](https://github.com/opencv/opencv/blob/4.x/samples/cpp/create_mask.cpp)
+
+use opencv::{
+	core::{bitwise_and, find_file, CommandLineParser, Point, Scalar, CV_8UC1, CV_8UC3},
+	highgui::{self, *},
+	imgcodecs::{imread, IMREAD_COLOR},
+	imgproc,
+	prelude::*,
+};
+
+use std::{
+	env, process,
+	sync::{
+		atomic::{self, AtomicBool},
+		Arc, Mutex,
+	},
+};
+
+const SOURCE_WINDOW: &str = "Source image";
+
+fn main() {
+	let args: Vec<String> = env::args().collect();
+	let (argc, argv) = (args.len() as i32, args.iter().map(|s| s.as_str()).collect::<Vec<&str>>());
+
+	let mut parser = CommandLineParser::new(argc, &argv, "{@input | lena.jpg | input image}").unwrap();
+	parser.about("This program demonstrates using mouse events\n").unwrap();
+	parser.print_message().unwrap();
+	println!(
+		"\n\tleft mouse button - set a point to create mask shape\n\
+            \tright mouse button - create mask from points\n\
+            \tmiddle mouse button - reset"
+	);
+
+	// HACK: replace with parser.get<String>("@input")
+	let input_image = "lena.jpg";
+	let input_image_path = find_file(input_image, true, false).expect("Cannot find input image");
+
+	let [src, mut img1, mut mask, mut final_img]: [Mat; 4];
+	src = imread(&input_image_path, IMREAD_COLOR).unwrap();
+	if src.empty() {
+		eprintln!("Error opening image: {}", input_image);
+		process::exit(-1);
+	}
+
+	highgui::named_window(SOURCE_WINDOW, WINDOW_AUTOSIZE).unwrap();
+	let mouse_event_data: (i32, i32, i32, i32) = Default::default();
+	let (mouse_event_data, should_handle_mouse_event) = (Arc::new(Mutex::new(mouse_event_data)), Arc::new(AtomicBool::new(false)));
+
+	let mouse_event_dispatcher = {
+		let mouse_data = Arc::clone(&mouse_event_data);
+		let should_handle_mouse_event = Arc::clone(&should_handle_mouse_event);
+
+		move |event: i32, x: i32, y: i32, flags: i32| {
+			// can intercept specific mouse events here to don't update the mouse_data
+			if let Ok(mut mouse_data) = mouse_data.lock() {
+				*mouse_data = (event, x, y, flags);
+			}
+			should_handle_mouse_event.store(true, atomic::Ordering::Relaxed);
+		}
+	};
+	highgui::set_mouse_callback(SOURCE_WINDOW, Some(Box::new(mouse_event_dispatcher))).expect("Cannot set mouse callback");
+
+	highgui::imshow(SOURCE_WINDOW, &src).unwrap();
+
+	let (mut num_points_has_add, mut drag_left_button, mut right_button_down) = (0, false, false);
+	let mut points = Vec::<Point>::new();
+
+	img1 = Mat::new_size_with_default(src.size().unwrap(), CV_8UC3, Scalar::new(0.0, 0.0, 0.0, 0.0)).unwrap();
+
+	loop {
+		// Press Esc to exit
+		if highgui::wait_key(10).unwrap() == 27 {
+			break;
+		}
+
+		let (mouse_event, x, y, _) = {
+			if !should_handle_mouse_event.load(atomic::Ordering::Relaxed) {
+				continue;
+			}
+			should_handle_mouse_event.store(false, atomic::Ordering::Relaxed);
+
+			if let Ok(mouse_event_data) = mouse_event_data.lock() {
+				*mouse_event_data
+			} else {
+				continue;
+			}
+		};
+
+		match mouse_event {
+			EVENT_LBUTTONDOWN => {
+				dbg!((mouse_event, x, y));
+
+				if !drag_left_button && !right_button_down {
+					if num_points_has_add == 0 {
+						img1 = src.clone();
+					}
+
+					let point = Point::new(x, y);
+					imgproc::circle(&mut img1, point, 2, Scalar::new(0., 0., 255., 0.), -1, imgproc::LINE_8, 0).unwrap();
+					points.push(point);
+					num_points_has_add += 1;
+					drag_left_button = true;
+
+					if num_points_has_add > 1 {
+						imgproc::line(
+							&mut img1,
+							points[num_points_has_add - 2],
+							point,
+							Scalar::new(0., 0., 255., 0.),
+							2,
+							imgproc::LINE_8,
+							0,
+						)
+						.unwrap();
+					}
+
+					imshow(SOURCE_WINDOW, &img1).unwrap();
+				}
+			}
+			EVENT_LBUTTONUP => {
+				dbg!((mouse_event, x, y));
+
+				if drag_left_button {
+					imshow(SOURCE_WINDOW, &img1).unwrap();
+					drag_left_button = false;
+				}
+			}
+			EVENT_RBUTTONDOWN => {
+				dbg!((mouse_event, x, y));
+
+				right_button_down = true;
+				let mut img1 = src.clone();
+
+				if num_points_has_add > 0 {
+					let pts_mat = Mat::from_slice(points.as_slice()).unwrap();
+					imgproc::polylines(&mut img1, &pts_mat, true, Scalar::new(0., 0., 0., 0.), 2, imgproc::LINE_8, 0).unwrap();
+				}
+
+				imshow(SOURCE_WINDOW, &img1).unwrap();
+			}
+			EVENT_RBUTTONUP => {
+				dbg!((mouse_event, x, y));
+
+				right_button_down = false;
+				final_img = Mat::zeros_size(src.size().unwrap(), CV_8UC3).unwrap().to_mat().unwrap();
+
+				mask = Mat::zeros_size(src.size().unwrap(), CV_8UC1).unwrap().to_mat().unwrap();
+
+				let points_mat = Mat::from_slice(points.as_slice()).unwrap();
+				imgproc::fill_poly(
+					&mut mask,
+					&points_mat,
+					Scalar::new(255., 255., 255., 255.),
+					imgproc::LINE_8,
+					0,
+					Point::default(),
+				)
+				.unwrap();
+
+				bitwise_and(&src, &src, &mut final_img, &mask).unwrap();
+
+				imshow("Mask", &mask).unwrap();
+				imshow("Result", &final_img).unwrap();
+				imshow(SOURCE_WINDOW, &img1).unwrap();
+			}
+			EVENT_MBUTTONDOWN => {
+				dbg!((mouse_event, x, y));
+
+				num_points_has_add = 0;
+				points.clear();
+				img1 = src.clone();
+				imshow(SOURCE_WINDOW, &img1).unwrap();
+			}
+			_ => {}
+		}
+	}
+}