From 4c1161c1fe583aa949fbd3a93145059439922eab Mon Sep 17 00:00:00 2001
From: JP Stringham <jp@bloomdigital.to>
Date: Mon, 5 Jan 2026 08:37:04 -0500
Subject: [PATCH] Vertical flip function added

---
 src/main.rs   |  4 +++-
 src/sh1106.rs | 29 ++++++++++++++++++++++++++---
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index bcac557..176e1d5 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -65,9 +65,11 @@ fn main() -> ! {
     let mut led_pin = pins.gpio25.into_push_pull_output();
     led_pin.set_high().unwrap();
 
-    let sh1106_dev = sh1106_pico_rs::sh1106::SH1106Dev::new(&mut delay, &mut i2c);
+    let mut sh1106_dev = sh1106_pico_rs::sh1106::SH1106Dev::new(&mut delay, &mut i2c);
     println!("SH1106 initialized.");
 
+    sh1106_dev.set_vertical_flip(&mut i2c, true);
+
     let mut gfx_buf = sh1106_pico_rs::graphics::GraphicsBuf::new();
 
     loop {
diff --git a/src/sh1106.rs b/src/sh1106.rs
index 5fa2bca..b0b3482 100644
--- a/src/sh1106.rs
+++ b/src/sh1106.rs
@@ -23,6 +23,7 @@ pub const SH1106_I2C_ADDR: u8 = 0x78u8 >> 1;
 
 pub struct SH1106Dev {
     ready: bool,
+    vertical_flip: bool,
 }
 
 impl SH1106Dev {
@@ -38,7 +39,25 @@ impl SH1106Dev {
         delay.delay_ms(500);
         send_command(&mut i2c, &SH1106Cmd::DisplayOnOff, 0x01);
 
-        SH1106Dev { ready: true }
+        SH1106Dev {
+            ready: true,
+            vertical_flip: false,
+        }
+    }
+
+    pub fn set_vertical_flip(&mut self, i2c: &mut dyn I2c<Error = Error>, flipped: bool) {
+        if !self.ready {
+            panic!("Attempted to use SSH1106 before initialized.");
+        }
+
+        self.vertical_flip = flipped;
+
+        let cmd = match flipped {
+            true => SH1106Cmd::ColDirectionRev,
+            false => SH1106Cmd::ColDirectionNorm,
+        };
+
+        send_command(i2c, &cmd, 0);
     }
 
     pub fn blit_framebuffer(&self, i2c: &mut dyn I2c<Error = Error>, gfx_buf: &GraphicsBuf) {
@@ -51,12 +70,12 @@ impl SH1106Dev {
         for r in 0..8 {
             set_page(i2c, r);
             set_col(i2c, 2);
+
             // for each cel of 8x8 pixels
             for c in 0..16 {
                 let mut cel = [0u8; 8];
 
                 // so our x,y here would be r * 128 + c * 8
-
                 // start assembling the 8x8 cel
                 for x in 0..8 {
                     let mut col_byte = 0u8;
@@ -65,7 +84,11 @@ impl SH1106Dev {
                     for y in 0..8 {
                         let pix_x = (c as usize) * 8 + x;
                         let pix_y = (r as usize) * 8 + y;
-                        col_byte |= buf[pix_y * 128 + pix_x] << y;
+                        let byte_index = match self.vertical_flip {
+                            true => pix_y * 128 + (127 - pix_x),
+                            false => pix_y * 128 + pix_x,
+                        };
+                        col_byte |= buf[byte_index] << y;
                     }
 
                     cel[x] = col_byte;