input/
render.rs

1use viewport::Viewport;
2
3use crate::{Event, Loop};
4
5/// Render arguments.
6#[derive(Copy, Clone, PartialEq, PartialOrd, Debug, Deserialize, Serialize)]
7pub struct RenderArgs {
8    /// Extrapolated time in seconds, used to do smooth animation.
9    pub ext_dt: f64,
10    /// The width and height of rendered area in points.
11    pub window_size: [f64; 2],
12    /// The width and height of rendered area in pixels.
13    pub draw_size: [u32; 2],
14}
15
16impl RenderArgs {
17    /// Returns viewport information filling entire render area.
18    pub fn viewport(&self) -> Viewport {
19        Viewport {
20            rect: [0, 0, self.draw_size[0] as i32, self.draw_size[1] as i32],
21            window_size: self.window_size,
22            draw_size: self.draw_size,
23        }
24    }
25}
26
27/// When the next frame should be rendered.
28pub trait RenderEvent: Sized {
29    /// Creates a render event.
30    fn from_render_args(args: &RenderArgs, old_event: &Self) -> Option<Self>;
31    /// Calls closure if this is a render event.
32    fn render<U, F>(&self, f: F) -> Option<U>
33    where
34        F: FnMut(&RenderArgs) -> U;
35    /// Returns render arguments.
36    fn render_args(&self) -> Option<RenderArgs> {
37        self.render(|args| *args)
38    }
39}
40
41impl RenderEvent for Event {
42    fn from_render_args(args: &RenderArgs, _old_event: &Self) -> Option<Self> {
43        Some(Event::Loop(Loop::Render(*args)))
44    }
45
46    fn render<U, F>(&self, mut f: F) -> Option<U>
47    where
48        F: FnMut(&RenderArgs) -> U,
49    {
50        match *self {
51            Event::Loop(Loop::Render(ref args)) => Some(f(args)),
52            _ => None,
53        }
54    }
55}
56
57#[cfg(test)]
58mod tests {
59    use super::*;
60
61    #[test]
62    fn test_input_render() {
63        use RenderArgs;
64
65        let e: Event = RenderArgs {
66            ext_dt: 0.0,
67            window_size: [0.0, 0.0],
68            draw_size: [0, 0],
69        }
70        .into();
71        let x: Option<Event> = RenderEvent::from_render_args(
72            &RenderArgs {
73                ext_dt: 1.0,
74                window_size: [10.0, 10.0],
75                draw_size: [10, 10],
76            },
77            &e,
78        );
79        let y: Option<Event> = x
80            .clone()
81            .unwrap()
82            .render(|args| RenderEvent::from_render_args(args, x.as_ref().unwrap()))
83            .unwrap();
84        assert_eq!(x, y);
85    }
86}
input/render.rs

input/
render.rs
