From 0446ba0d69a2a3a343b2798ca60b2623571735e5 Mon Sep 17 00:00:00 2001
From: James Jackson-South <james_south@hotmail.com>
Date: Sat, 5 Sep 2026 01:16:21 +1000
Subject: [PATCH] Cover large PNG average-filter scanlines

---
 tests/ImageSharp.Tests/Formats/Png/PngDecoderCoreTests.cs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tests/ImageSharp.Tests/Formats/Png/PngDecoderCoreTests.cs b/tests/ImageSharp.Tests/Formats/Png/PngDecoderCoreTests.cs
index 0b442f8834..95c452c0f8 100644
--- a/tests/ImageSharp.Tests/Formats/Png/PngDecoderCoreTests.cs
+++ b/tests/ImageSharp.Tests/Formats/Png/PngDecoderCoreTests.cs
@@ -15,4 +15,12 @@ public class PngDecoderCoreTests
 
         Assert.Equal(536_870_913, length);
     }
+
+    [Fact]
+    public void CalculateScanlineLength_WithLargeRgbaWidth_ReturnsExpectedLength()
+    {
+        int length = PngDecoderCore.CalculateScanlineLength(33_554_432, 16, 8);
+
+        Assert.Equal(268_435_456, length);
+    }
 }