Fix SixLabors#2907. Wrong rgb used for color table

zabulus · zabulus · commit 940076087a08 · 2025-04-11T11:08:20.000-04:00
diff --git a/src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs b/src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs
@@ -1597,8 +1597,8 @@ private int ReadImageHeaders(BufferedReadStream stream, out bool inverted, out b
 
         if (palette.Length > 0)
         {
-            Color[] colorTable = new Color[palette.Length / Unsafe.SizeOf<Bgr24>()];
-            ReadOnlySpan<Bgr24> rgbTable = MemoryMarshal.Cast<byte, Bgr24>(palette);
+            Color[] colorTable = new Color[palette.Length / Unsafe.SizeOf<Bgra32>()];
+            ReadOnlySpan<Bgra32> rgbTable = MemoryMarshal.Cast<byte, Bgra32>(palette);
             Color.FromPixel(rgbTable, colorTable);
             this.bmpMetadata.ColorTable = colorTable;
         }

Original file line number	Diff line number	Diff line change
`@@ -1597,8 +1597,8 @@ private int ReadImageHeaders(BufferedReadStream stream, out bool inverted, out b`
`1597`	`1597`
`1598`	`1598`	`if (palette.Length > 0)`
`1599`	`1599`	`{`
`1600`		`- Color[] colorTable = new Color[palette.Length / Unsafe.SizeOf<Bgr24>()];`
`1601`		`- ReadOnlySpan<Bgr24> rgbTable = MemoryMarshal.Cast<byte, Bgr24>(palette);`
	`1600`	`+ Color[] colorTable = new Color[palette.Length / Unsafe.SizeOf<Bgra32>()];`
	`1601`	`+ ReadOnlySpan<Bgra32> rgbTable = MemoryMarshal.Cast<byte, Bgra32>(palette);`
`1602`	`1602`	`Color.FromPixel(rgbTable, colorTable);`
`1603`	`1603`	`this.bmpMetadata.ColorTable = colorTable;`
`1604`	`1604`	`}`