From b6d329473d1dbe1b765727183958b12afddf859f Mon Sep 17 00:00:00 2001
From: Maria Pospelova <mariapospelova@google.com>
Date: Fri, 29 May 2026 13:21:42 +0000
Subject: [PATCH 1/2] Zero all channels for AND-mask-transparent pixels

---
 src/codecs/ico/decoder.rs                       |   4 ++--
 .../reference/ico/images/bmp-24bpp-mask.ico.png | Bin 700 -> 612 bytes
 .../ico/images/bmp-32bpp-alpha.ico.png          | Bin 700 -> 612 bytes
 3 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/codecs/ico/decoder.rs b/src/codecs/ico/decoder.rs
index b7fe270996..7316a5c5ff 100644
--- a/src/codecs/ico/decoder.rs
+++ b/src/codecs/ico/decoder.rs
@@ -396,8 +396,8 @@ impl<R: BufRead + Seek> ImageDecoder for IcoDecoder<R> {
                                 }
 
                                 if mask_byte & (1 << bit) != 0 {
-                                    // Set alpha channel to transparent.
-                                    row[x as usize][3] = 0;
+                                    // Set pixel to fully transparent black.
+                                    row[x as usize] = [0, 0, 0, 0];
                                 }
 
                                 x += 1;
diff --git a/tests/reference/ico/images/bmp-24bpp-mask.ico.png b/tests/reference/ico/images/bmp-24bpp-mask.ico.png
index 77b763e7230306001f7bf90bdf6449d9cd1829f5..0972df048234ef3d29ba86890851b54db7eaad74 100644
GIT binary patch
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diff --git a/tests/reference/ico/images/bmp-32bpp-alpha.ico.png b/tests/reference/ico/images/bmp-32bpp-alpha.ico.png
index 77b763e7230306001f7bf90bdf6449d9cd1829f5..0972df048234ef3d29ba86890851b54db7eaad74 100644
GIT binary patch
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From 657fce5294cf3282ee24de94912c0887541a2812 Mon Sep 17 00:00:00 2001
From: Maria Pospelova <mariapospelova@google.com>
Date: Fri, 29 May 2026 13:35:18 +0000
Subject: [PATCH 2/2] Change wording of comment

---
 src/codecs/ico/decoder.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/codecs/ico/decoder.rs b/src/codecs/ico/decoder.rs
index 7316a5c5ff..8876fb3b4f 100644
--- a/src/codecs/ico/decoder.rs
+++ b/src/codecs/ico/decoder.rs
@@ -396,7 +396,7 @@ impl<R: BufRead + Seek> ImageDecoder for IcoDecoder<R> {
                                 }
 
                                 if mask_byte & (1 << bit) != 0 {
-                                    // Set pixel to fully transparent black.
+                                    // Set pixel to fully transparent.
                                     row[x as usize] = [0, 0, 0, 0];
                                 }