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use std::any::Any;
use viewport::Viewport;
use { GenericEvent, RENDER };
#[derive(Copy, Clone, PartialEq, Debug)]
pub struct RenderArgs {
pub ext_dt: f64,
pub width: u32,
pub height: u32,
pub draw_width: u32,
pub draw_height: u32,
}
impl RenderArgs {
pub fn viewport(&self) -> Viewport {
Viewport {
rect: [0, 0, self.draw_width as i32, self.draw_height as i32],
window_size: [self.width, self.height],
draw_size: [self.draw_width, self.draw_height],
}
}
}
pub trait RenderEvent: Sized {
fn from_render_args(args: &RenderArgs, old_event: &Self) -> Option<Self>;
fn render<U, F>(&self, f: F) -> Option<U>
where F: FnMut(&RenderArgs) -> U;
fn render_args(&self) -> Option<RenderArgs> {
self.render(|args| args.clone())
}
}
impl<T: GenericEvent> RenderEvent for T {
fn from_render_args(args: &RenderArgs, old_event: &Self) -> Option<Self> {
GenericEvent::from_args(RENDER, args as &Any, old_event)
}
fn render<U, F>(&self, mut f: F) -> Option<U>
where F: FnMut(&RenderArgs) -> U
{
if self.event_id() != RENDER {
return None;
}
self.with_args(|any| {
if let Some(args) = any.downcast_ref::<RenderArgs>() {
Some(f(args))
} else {
panic!("Expected RenderArgs")
}
})
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_event_render() {
use Event;
use RenderArgs;
let e = Event::Render(RenderArgs { ext_dt: 0.0, width: 0, height: 0,
draw_width: 0, draw_height: 0 });
let x: Option<Event> = RenderEvent::from_render_args(
&RenderArgs {
ext_dt: 1.0,
width: 10,
height: 10,
draw_width: 10,
draw_height: 10,
}, &e
);
let y: Option<Event> = x.clone().unwrap().render(|args|
RenderEvent::from_render_args(args, x.as_ref().unwrap())).unwrap();
assert_eq!(x, y);
}
}