touch_visualizer/
lib.rs

1//! A library for visualizing input touches with Piston-Graphics
2
3#![deny(unreachable_pub)]
4
5extern crate graphics;
6extern crate input;
7
8use std::collections::HashMap;
9
10use input::{GenericEvent, Touch};
11use graphics::{Context, Graphics};
12
13/// Stores touch values.
14pub type TouchValues = HashMap<(i64, i64), ([f64; 2], f64)>;
15
16/// Visualizes touch input.
17#[derive(Clone, Debug)]
18pub struct TouchVisualizer {
19    /// Stores touch values.
20    pub touch_values: TouchValues,
21    window_size: Option<[u32; 2]>,
22}
23
24impl TouchVisualizer {
25    /// Creates a new touch visualizer.
26    pub fn new() -> TouchVisualizer {
27        TouchVisualizer {
28            touch_values: HashMap::new(),
29            window_size: None,
30        }
31    }
32
33    /// Draws touch visual graphics.
34    pub fn draw<G: Graphics>(&self, c: &Context, g: &mut G) {
35        use graphics::ellipse::Ellipse;
36
37        let window_size = if let Some(size) = self.window_size {
38            size
39        } else {
40            return;
41        };
42        let color = [1.0, 0.0, 0.0, 0.4];
43        let radius = 20.0;
44        let mut draw = |pos: [f64; 2], pressure: f64| {
45            let r = radius * pressure;
46            let x = pos[0] * window_size[0] as f64 - r;
47            let y = pos[1] * window_size[1] as f64 - r;
48            let w = 2.0 * r;
49            Ellipse::new(color)
50                .resolution(16)
51                .draw([x, y, w, w], &c.draw_state, c.transform, g);
52        };
53        for &(pos, pressure) in self.touch_values.values() {
54            draw(pos, pressure);
55        }
56    }
57
58    /// Handles event.
59    pub fn event<E: GenericEvent, S: Into<[u32; 2]>>(&mut self, window_size: S, e: &E) {
60        self.window_size = Some(window_size.into());
61        if let Some(args) = e.touch_args() {
62            match args.touch {
63                Touch::Start | Touch::Move => {
64                    self.touch_values
65                        .insert((args.device, args.id), (args.position(), args.pressure()));
66                }
67                Touch::End | Touch::Cancel => {
68                    self.touch_values.remove(&(args.device, args.id));
69                }
70            }
71        }
72    }
73}
touch_visualizer/lib.rs

touch_visualizer/
lib.rs
