produce events in dummy capture-backend (#184)

input-capture/src/dummy.rs

@@ -1,16 +1,28 @@
+use std::f64::consts::PI;
 use std::pin::Pin;
-use std::task::{Context, Poll};
+use std::task::{ready, Context, Poll};
+use std::time::Duration;
 
 use async_trait::async_trait;
 use futures_core::Stream;
+use input_event::PointerEvent;
+use tokio::time::{self, Instant, Interval};
 
 use super::{Capture, CaptureError, CaptureEvent, CaptureHandle, Position};
 
-pub struct DummyInputCapture {}
+pub struct DummyInputCapture {
+    start: Option<Instant>,
+    interval: Interval,
+    offset: (i32, i32),
+}
 
 impl DummyInputCapture {
     pub fn new() -> Self {
-        Self {}
+        Self {
+            start: None,
+            interval: time::interval(Duration::from_millis(1)),
+            offset: (0, 0),
+        }
     }
 }
 
@@ -39,10 +51,36 @@ impl Capture for DummyInputCapture {
     }
 }
 
+const FREQUENCY_HZ: f64 = 1.0;
+const RADIUS: f64 = 100.0;
+
 impl Stream for DummyInputCapture {
     type Item = Result<(CaptureHandle, CaptureEvent), CaptureError>;
 
-    fn poll_next(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
-        Poll::Pending
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        let current = ready!(self.interval.poll_tick(cx));
+        let event = match self.start {
+            None => {
+                self.start.replace(current);
+                CaptureEvent::Begin
+            }
+            Some(start) => {
+                let elapsed = start.elapsed();
+                let elapsed_sec_f64 = elapsed.as_secs_f64();
+                let second_fraction = elapsed_sec_f64 - elapsed_sec_f64 as u64 as f64;
+                let radians = second_fraction * 2. * PI * FREQUENCY_HZ;
+                let offset = (radians.cos() * RADIUS * 2., (radians * 2.).sin() * RADIUS);
+                let offset = (offset.0 as i32, offset.1 as i32);
+                let relative_motion = (offset.0 - self.offset.0, offset.1 - self.offset.1);
+                self.offset = offset;
+                let (dx, dy) = (relative_motion.0 as f64, relative_motion.1 as f64);
+                CaptureEvent::Input(input_event::Event::Pointer(PointerEvent::Motion {
+                    time: 0,
+                    dx,
+                    dy,
+                }))
+            }
+        };
+        Poll::Ready(Some(Ok((0, event))))
     }
 }