From 0804a166396e1129cd70f8b7b5e988e844e0721e Mon Sep 17 00:00:00 2001
From: Zac Wilson <zac@zacjw.com>
Date: Sun, 21 Dec 2025 13:36:32 +0000
Subject: [PATCH] Fixed draw_pixel

---
 src/lib.rs | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index f0376f9..124fd38 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -217,17 +217,20 @@ impl DoubleFrame<AutomaticPartialWindow> {
 
 impl<PartialWindow: ApplyPartialWindow> DoubleFrame<PartialWindow> {
     pub fn draw_pixel(&mut self, x: u16, y: u16, colour: PixelColour) {
+        if x >= EPD_WIDTH as u16 || y >= EPD_HEIGHT as u16 {
+            return; // pixel is offscreen so can be skipped
+        }
         self.partial_window.update_partial_window(x, x, y, y);
-        let x_i = x / 8;
-        let x_shift = x % 8;
-        let i = y * (EPD_WIDTH as u16 / 8) + x_i;
+        let x_i = x as usize / 8;
+        let x_shift = 7 - (x % 8);
+        let i = y as usize * (EPD_WIDTH / 8) + x_i;
         match colour {
             PixelColour::Black => {
                 self.new.0[i as usize] &= !(1 << x_shift);
-            },
+            }
             PixelColour::White => {
                 self.new.0[i as usize] |= 1 << x_shift;
-            },
+            }
         }
     }
 }