From 593103cd8bdae024e28932c94ce5441283161393 Mon Sep 17 00:00:00 2001
From: Aidan MacDonald <amachronic@protonmail.com>
Date: Sun, 8 Jan 2023 10:44:47 +0000
Subject: [PATCH] lcd: Fix 4bpp optimized 16-bit alpha blit

Fixes a bug introduced by commit 5d0c382a59 that caused graphical
corruption on anti-aliased fonts.

Change-Id: I6052ca758382bd9a1154d2e2208dee633dd17715
---
 firmware/drivers/lcd-16bit-common.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/firmware/drivers/lcd-16bit-common.c b/firmware/drivers/lcd-16bit-common.c
index af1171b401..9d24dfe16e 100644
--- a/firmware/drivers/lcd-16bit-common.c
+++ b/firmware/drivers/lcd-16bit-common.c
@@ -498,10 +498,11 @@ static void ICODE_ATTR lcd_alpha_bitmap_part_mix(
         if (stride_alpha) { \
             alpha_pixels = stride_alpha - alpha_pixels; \
             alpha += alpha_pixels / ALPHA_PIXELS_PER_BYTE; \
-            alpha_data = *alpha++ ^ dmask; \
             alpha_pixels &= 1; \
-            if (alpha_pixels) \
+            if (alpha_pixels) { \
+                alpha_data = *alpha++ ^ dmask; \
                 alpha_data >>= ALPHA_BPP; \
+            } \
         } \
     } while(0)
 #define READ_ALPHA() \