add get_pixel to buffered_graphics

see also: rust-embedded-community#192

src/mode/buffered_graphics.rs

@@ -156,13 +156,8 @@ 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;
-
- let (idx, bit) = match rotation {
+ fn pixel_location(&self, x: u32, y: u32) -> (usize, u32) {
+ match rotation {
  DisplayRotation::Rotate0 | DisplayRotation::Rotate180 => {
  let idx = ((y as usize) / 8 * SIZE::WIDTH as usize) + (x as usize);
  let bit = y % 8;
@@ -175,7 +170,21 @@ where
 
  (idx, bit)
  }
- };
+ }
+ }
+
+ pub fn get_pixel(&self, x: u32, y: u32) -> Option<bool> {
+ let (idx, bit) = self.pixel_location(x,y);
+ self.mode.buffer.as_mut().get(idx).map(|byte| byte & !(1 << bit) != 0)
+ }
+
+ /// 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;
+
+ let (idx, bit) = self.pixel_location(x,y);
 
  if let Some(byte) = self.mode.buffer.as_mut().get_mut(idx) {
  // Keep track of max and min values