As a result of the previous commit, we are now getting events from th…

…e Wacom decoder at a significantly higher rate and therefore we need a quick way to deduplicate refreshes. Better alternatives would include timestamping which should be doable with low overhead since the events we get from the device actually have usec granularity timestamps

examples/demo.rs

@@ -12,6 +12,10 @@ extern crate libremarkable;
 
 extern crate chrono;
 
+extern crate atomic;
+
+use atomic::Atomic;
+
 use chrono::{DateTime, Local};
 
 use std::sync::Mutex;
@@ -115,15 +119,22 @@ fn on_wacom_input(app: &mut appctx::ApplicationContext, input: wacom::WacomEvent
                     rad as usize,
                     color,
                 );
-                framebuffer.partial_refresh(
-                    &rect,
-                    PartialRefreshMode::Async,
-                    waveform_mode::WAVEFORM_MODE_DU,
-                    display_temp::TEMP_USE_REMARKABLE_DRAW,
-                    dither_mode::EPDC_FLAG_EXP1,
-                    DRAWING_QUANT_BIT,
-                    false,
-                );
+
+                if !LAST_REFRESHED_CANVAS_RECT
+                    .load(Ordering::Relaxed)
+                    .contains_rect(&rect)
+                {
+                    framebuffer.partial_refresh(
+                        &rect,
+                        PartialRefreshMode::Async,
+                        waveform_mode::WAVEFORM_MODE_DU,
+                        display_temp::TEMP_USE_REMARKABLE_DRAW,
+                        dither_mode::EPDC_FLAG_EXP1,
+                        DRAWING_QUANT_BIT,
+                        false,
+                    );
+                    LAST_REFRESHED_CANVAS_RECT.store(rect, Ordering::Relaxed);
+                }
             }
             wacom_stack.push((y as i32, x as i32));
         }
@@ -565,6 +576,7 @@ lazy_static! {
     static ref WACOM_IN_RANGE: AtomicBool = AtomicBool::new(false);
     static ref WACOM_HISTORY: Mutex<Vec<(i32, i32)>> = Mutex::new(Vec::new());
     static ref G_COUNTER: Mutex<u32> = Mutex::new(0);
+    static ref LAST_REFRESHED_CANVAS_RECT: Atomic<mxcfb_rect> = Atomic::new(mxcfb_rect::invalid());
     static ref SAVED_CANVAS: Mutex<Option<storage::CompressedCanvasState>> = Mutex::new(None);
 }
 

src/framebuffer/common.rs

@@ -171,6 +171,11 @@ impl mxcfb_rect {
             || y < self.top
             || y > (self.top + self.height))
     }
+
+    pub fn contains_rect(&self, rect: &mxcfb_rect) -> bool {
+        self.contains_point(rect.top, rect.left)
+            && self.contains_point(rect.top + rect.height, rect.left + rect.width)
+    }
 }
 
 #[derive(Copy, Clone, Debug, PartialEq)]