add get_pixel & toggle_pixel & extract shared code

src/mode/buffered_graphics.rs

@@ -156,39 +156,56 @@ where
         }
     }
 
-    /// Turn a pixel on or off. A non-zero `value` is treated as on, `0` as off. If the X and Y
-    /// coordinates are out of the bounds of the display, this method call is a noop.
-    pub fn set_pixel(&mut self, x: u32, y: u32, value: bool) {
-        let value = value as u8;
-        let rotation = self.rotation;
+    fn pixel_location(&self, x: u32, y: u32) -> Option<(usize, u32)> {
+        let (x_rotated, y_rotated) = match self.rotation {
+            DisplayRotation::Rotate0 | DisplayRotation::Rotate180 => (x, y),
+            DisplayRotation::Rotate90 | DisplayRotation::Rotate270 => (y, x),
+        };
+        if x_rotated >= SIZE::WIDTH as u32 || y_rotated >= SIZE::HEIGHT as u32 {
+            None
+        } else {
+            let idx = ((y_rotated as usize) / 8 * SIZE::WIDTH as usize) + (x_rotated as usize);
+            let bit = y_rotated % 8;
+            Some((idx, bit))
+        }
+    }
 
-        let (idx, bit) = match rotation {
-            DisplayRotation::Rotate0 | DisplayRotation::Rotate180 => {
-                let idx = ((y as usize) / 8 * SIZE::WIDTH as usize) + (x as usize);
-                let bit = y % 8;
+    fn track_change(&mut self, x: u32, y: u32) {
+        self.mode.min_x = self.mode.min_x.min(x as u8);
+        self.mode.max_x = self.mode.max_x.max(x as u8);
+        self.mode.min_y = self.mode.min_y.min(y as u8);
+        self.mode.max_y = self.mode.max_y.max(y as u8);
+    }
 
-                (idx, bit)
-            }
-            DisplayRotation::Rotate90 | DisplayRotation::Rotate270 => {
-                let idx = ((x as usize) / 8 * SIZE::WIDTH as usize) + (y as usize);
-                let bit = x % 8;
+    pub fn get_pixel(&self, x: u32, y: u32) -> Option<bool> {
+        self.pixel_location(x, y).and_then(|(idx, bit)| {
+            self.mode
+                .buffer
+                .as_ref()
+                .get(idx)
+                .map(|byte| byte & (1 << bit) != 0)
+        })
+    }
 
-                (idx, bit)
+    /// Turn a pixel on or off. If the coordinates are out of bounds for the display, this method call is a noop
+    pub fn set_pixel(&mut self, x: u32, y: u32, value: bool) {
+        self.pixel_location(x, y).map(|(idx, bit)| {
+            self.track_change(x, y);
+            if let Some(byte) = self.mode.buffer.as_mut().get_mut(idx) {
+                // Ref this comment https://stackoverflow.com/questions/47981/how-do-you-set-clear-and-toggle-a-single-bit#comment46654671_47990
+                *byte = *byte & !(1 << bit) | ((value as u8) << bit) // Set pixel value in byte
             }
-        };
-
-        if let Some(byte) = self.mode.buffer.as_mut().get_mut(idx) {
-            // Keep track of max and min values
-            self.mode.min_x = self.mode.min_x.min(x as u8);
-            self.mode.max_x = self.mode.max_x.max(x as u8);
-
-            self.mode.min_y = self.mode.min_y.min(y as u8);
-            self.mode.max_y = self.mode.max_y.max(y as u8);
+        });
+    }
 
-            // Set pixel value in byte
-            // Ref this comment https://stackoverflow.com/questions/47981/how-do-you-set-clear-and-toggle-a-single-bit#comment46654671_47990
-            *byte = *byte & !(1 << bit) | (value << bit)
-        }
+    /// Toggle a pixel to the opposite of it's current state. If the coordinates are out of bounds for the display, this method call is a noop
+    pub fn toggle_pixel(&mut self, x: u32, y: u32) {
+        self.pixel_location(x, y).map(|(idx, bit)| {
+            self.track_change(x, y);
+            if let Some(byte) = self.mode.buffer.as_mut().get_mut(idx) {
+                *byte = *byte ^ (1 << bit) // toggle pixel in byte
+            }
+        });
     }
 }
 

src/size.rs

@@ -40,7 +40,7 @@ pub trait DisplaySize {
 
     /// Size of framebuffer. Because the display is monochrome, this is
     /// width * height / 8
-    type Buffer: AsMut<[u8]> + NewZeroed;
+    type Buffer: AsRef<[u8]> + AsMut<[u8]> + NewZeroed;
 
     /// Send resolution and model-dependent configuration to the display
     ///