Minor fixups

src/color.rs

@@ -185,4 +185,14 @@ mod tests {
         assert_eq!(Color::from(Color::White.get_bit_value()), Color::White);
         assert_eq!(Color::from(1u8).get_bit_value(), 1u8);
     }
+
+    #[test]
+    fn test_oct() {
+        let left = OctColor::Red;
+        let right = OctColor::Green;
+        assert_eq!(
+            OctColor::split_byte(OctColor::colors_byte(left, right)),
+            Ok((left, right))
+        );
+    }
 }

src/epd5in65f/graphics.rs

@@ -204,4 +204,48 @@ mod tests {
             );
         }
     }
+
+    #[test]
+    fn graphics_colors() {
+        let mut display = Display5in65f::default();
+
+        const COLORS: [OctColor; 8] = [
+            OctColor::HiZ,
+            OctColor::White,
+            OctColor::Black,
+            OctColor::Red,
+            OctColor::Green,
+            OctColor::Orange,
+            OctColor::Blue,
+            OctColor::Yellow,
+        ];
+        for c in &COLORS {
+            display.clear_buffer(*c);
+            for b in display.buffer() {
+                assert_eq!(OctColor::split_byte(*b), Ok((*c, *c)));
+            }
+        }
+
+        for (w, c) in (0..WIDTH).zip(COLORS.iter().cycle()) {
+            let _ = Line::new(
+                Point::new(w as i32, 0),
+                Point::new(w as i32, HEIGHT as i32 - 1),
+            )
+            .into_styled(PrimitiveStyle::with_stroke(*c, 1))
+            .draw(&mut display);
+        }
+
+        COLORS
+            .chunks(2)
+            .cycle()
+            .take(WIDTH as usize * 2)
+            .cycle()
+            .zip(display.buffer())
+            .for_each(|(window, b)| match (window, b) {
+                (&[c1, c2], b) => {
+                    assert_eq!(OctColor::split_byte(*b), Ok((c1, c2)));
+                }
+                _ => panic!("unexpected pattern"),
+            })
+    }
 }

src/graphics.rs

@@ -93,9 +93,9 @@ pub trait Display: DrawTarget<BinaryColor> {
 /// - Clearing
 pub trait OctDisplay: DrawTarget<OctColor> {
     /// Clears the buffer of the display with the chosen background color
-    fn clear_buffer(&mut self, background_color: Color) {
+    fn clear_buffer(&mut self, background_color: OctColor) {
         for elem in self.get_mut_buffer().iter_mut() {
-            *elem = background_color.get_byte_value();
+            *elem = OctColor::colors_byte(background_color, background_color);
         }
     }
 
@@ -274,7 +274,9 @@ fn find_rotation(x: u32, y: u32, width: u32, height: u32, rotation: DisplayRotat
 fn find_oct_position(x: u32, y: u32, width: u32, height: u32, rotation: DisplayRotation) -> (u32, bool) {
     let (nx, ny) = find_rotation(x, y, width, height, rotation);
     (
+        /* what byte address is this? */
         nx / 2 + (width / 2) * ny,
+        /* is this the lower nibble (within byte)? */
         (nx & 0x1) == 0,
     )
 }