Merge pull request #3032 from Socolin/fix-3031

Fix decoding tiff image with BigEndian + 64 bit / pixel + associated alpha
2 months ago · bca2fbcc4a
11 changed files with 126 additions and 29 deletions
--- a/.github/workflows/build-and-test.yml
+++ b/.github/workflows/build-and-test.yml
@ -69,12 +69,6 @@ jobs:
            sdk-preview: true
            runtime: -x64
            codecov: false
-          - os: macos-13 # macos-latest runs on arm64 runners where libgdiplus is unavailable
-            framework: net10.0
-            sdk: 10.0.x
-            sdk-preview: true
-            runtime: -x64
-            codecov: false
          - os: macos-26
            framework: net10.0
            sdk: 10.0.x
@ -99,11 +93,6 @@ jobs:
            sdk: 8.0.x
            runtime: -x64
            codecov: false
-          - os: macos-13 # macos-latest runs on arm64 runners where libgdiplus is unavailable
-            framework: net8.0
-            sdk: 8.0.x
-            runtime: -x64
-            codecov: false
          - os: macos-26
            framework: net8.0
            sdk: 8.0.x
--- a/src/ImageSharp/Formats/Tiff/PhotometricInterpretation/Rgba16161616TiffColor{TPixel}.cs
+++ b/src/ImageSharp/Formats/Tiff/PhotometricInterpretation/Rgba16161616TiffColor{TPixel}.cs
@ -1,5 +1,6 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
+
 #nullable disable

 using System.Buffers;
@ -48,31 +49,53 @@ internal class Rgba16161616TiffColor<TPixel> : TiffBaseColorDecoder<TPixel>

        using IMemoryOwner<Vector4> vectors = hasAssociatedAlpha ? this.memoryAllocator.Allocate<Vector4>(width) : null;
        Span<Vector4> vectorsSpan = hasAssociatedAlpha ? vectors.GetSpan() : [];
-        for (int y = top; y < top + height; y++)
-        {
-            Span<TPixel> pixelRow = pixels.DangerousGetRowSpan(y).Slice(left, width);

-            if (this.isBigEndian)
+        if (this.isBigEndian)
+        {
+            if (hasAssociatedAlpha)
            {
-                for (int x = 0; x < pixelRow.Length; x++)
+                for (int y = top; y < top + height; y++)
                {
-                    ushort r = TiffUtilities.ConvertToUShortBigEndian(data.Slice(offset, 2));
-                    offset += 2;
-                    ushort g = TiffUtilities.ConvertToUShortBigEndian(data.Slice(offset, 2));
-                    offset += 2;
-                    ushort b = TiffUtilities.ConvertToUShortBigEndian(data.Slice(offset, 2));
-                    offset += 2;
-                    ushort a = TiffUtilities.ConvertToUShortBigEndian(data.Slice(offset, 2));
-                    offset += 2;
-
-                    pixelRow[x] = hasAssociatedAlpha
-                        ? TiffUtilities.ColorFromRgba64Premultiplied<TPixel>(r, g, b, a)
-                        : TPixel.FromRgba64(new Rgba64(r, g, b, a));
+                    Span<TPixel> pixelRow = pixels.DangerousGetRowSpan(y).Slice(left, width);
+
+                    for (int x = 0; x < pixelRow.Length; x++)
+                    {
+                        ushort r = TiffUtilities.ConvertToUShortBigEndian(data.Slice(offset, 2));
+                        ushort g = TiffUtilities.ConvertToUShortBigEndian(data.Slice(offset + 2, 2));
+                        ushort b = TiffUtilities.ConvertToUShortBigEndian(data.Slice(offset + 4, 2));
+                        ushort a = TiffUtilities.ConvertToUShortBigEndian(data.Slice(offset + 6, 2));
+                        offset += 8;
+
+                        pixelRow[x] = TiffUtilities.ColorFromRgba64Premultiplied<TPixel>(r, g, b, a);
+                    }
                }
            }
            else
            {
+                for (int y = top; y < top + height; y++)
+                {
+                    Span<TPixel> pixelRow = pixels.DangerousGetRowSpan(y).Slice(left, width);
+
+                    for (int x = 0; x < pixelRow.Length; x++)
+                    {
+                        ushort r = TiffUtilities.ConvertToUShortBigEndian(data.Slice(offset, 2));
+                        ushort g = TiffUtilities.ConvertToUShortBigEndian(data.Slice(offset + 2, 2));
+                        ushort b = TiffUtilities.ConvertToUShortBigEndian(data.Slice(offset + 4, 2));
+                        ushort a = TiffUtilities.ConvertToUShortBigEndian(data.Slice(offset + 6, 2));
+                        offset += 8;
+
+                        pixelRow[x] = TPixel.FromRgba64(new Rgba64(r, g, b, a));
+                    }
+                }
+            }
+        }
+        else
+        {
+            for (int y = top; y < top + height; y++)
+            {
+                Span<TPixel> pixelRow = pixels.DangerousGetRowSpan(y).Slice(left, width);
                int byteCount = pixelRow.Length * 8;
+
                PixelOperations<TPixel>.Instance.FromRgba64Bytes(
                    this.configuration,
                    data.Slice(offset, byteCount),
--- a/src/ImageSharp/Formats/Tiff/Utils/TiffUtilities.cs
+++ b/src/ImageSharp/Formats/Tiff/Utils/TiffUtilities.cs
@ -45,7 +45,12 @@ internal static class TiffUtilities
            return TPixel.FromRgba64(default);
        }

-        return TPixel.FromRgba64(new Rgba64((ushort)(r / a), (ushort)(g / a), (ushort)(b / a), a));
+        float scale = 65535f / a;
+        ushort ur = (ushort)Math.Min(r * scale, 65535);
+        ushort ug = (ushort)Math.Min(g * scale, 65535);
+        ushort ub = (ushort)Math.Min(b * scale, 65535);
+
+        return TPixel.FromRgba64(new Rgba64(ur, ug, ub, a));
    }

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
--- a/tests/ImageSharp.Tests/Formats/Tiff/TiffDecoderTests.cs
+++ b/tests/ImageSharp.Tests/Formats/Tiff/TiffDecoderTests.cs
@ -365,6 +365,19 @@ public class TiffDecoderTests : TiffDecoderBaseTester
        image.CompareToReferenceOutput(ImageComparer.TolerantPercentage(0.0001F), provider);
    }

+    [Theory]
+    [WithFile(Issues3031, PixelTypes.Rgba64)]
+    [WithFile(Rgba16BitAssociatedAlphaBigEndian, PixelTypes.Rgba64)]
+    [WithFile(Rgba16BitAssociatedAlphaLittleEndian, PixelTypes.Rgba64)]
+    public void TiffDecoder_CanDecode_64Bit_WithAssociatedAlpha<TPixel>(TestImageProvider<TPixel> provider)
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        using Image<TPixel> image = provider.GetImage(TiffDecoder.Instance);
+        image.DebugSave(provider);
+
+        image.CompareToReferenceOutput(ImageComparer.Exact, provider);
+    }
+
    [Theory]
    [WithFile(Issues2454_A, PixelTypes.Rgba32)]
    [WithFile(Issues2454_B, PixelTypes.Rgba32)]
--- a/tests/ImageSharp.Tests/Formats/Tiff/Utils/TiffUtilitiesTest.cs
+++ b/tests/ImageSharp.Tests/Formats/Tiff/Utils/TiffUtilitiesTest.cs
@ -0,0 +1,51 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using SixLabors.ImageSharp.Formats.Tiff.Utils;
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp.Tests.Formats.Tiff.Utils;
+
+[Trait("Format", "Tiff")]
+public class TiffUtilitiesTest
+{
+    [Theory]
+    [InlineData(0, 0, 0, 0)]
+    [InlineData(42, 84, 128, 0)]
+    [InlineData(65535, 65535, 65535, 0)]
+    public void ColorFromRgba64Premultiplied_WithZeroAlpha_ReturnsDefaultPixel(ushort r, ushort g, ushort b, ushort a)
+    {
+        Rgba64 actual = TiffUtilities.ColorFromRgba64Premultiplied<Rgba64>(r, g, b, a);
+
+        Assert.Equal(default, actual);
+    }
+
+    [Theory]
+    [InlineData(65535, 65535, 65535, 65535, 65535, 65535, 65535, 65535)]
+    [InlineData(32767, 0, 0, 65535, 32767, 0, 0, 65535)]
+    [InlineData(0, 32767, 0, 65535, 0, 32767, 0, 65535)]
+    [InlineData(0, 0, 32767, 65535, 0, 0, 32767, 65535)]
+    public void ColorFromRgba64Premultiplied_WithNoAlpha_ReturnExpectedValues(ushort r, ushort g, ushort b, ushort a, ushort expectedR, ushort expectedG, ushort expectedB, ushort expectedA)
+    {
+        Rgba64 actual = TiffUtilities.ColorFromRgba64Premultiplied<Rgba64>(r, g, b, a);
+
+        Assert.Equal(new Rgba64(expectedR, expectedG, expectedB, expectedA), actual);
+    }
+
+    [Theory]
+    [InlineData(32766, 0, 0, 32766, 65535, 0, 0, 32766)] // Red, 50% Alpha
+    [InlineData(0, 32766, 0, 32766, 0, 65535, 0, 32766)] // Green, 50% Alpha
+    [InlineData(0, 0, 32766, 32766, 0, 0, 65535, 32766)] // Blue, 50% Alpha
+    [InlineData(8191, 0, 0, 16383, 32765, 0, 0, 16383)] // Red, 25% Alpha
+    [InlineData(0, 8191, 0, 16383, 0, 32765, 0, 16383)] // Green, 25% Alpha
+    [InlineData(0, 0, 8191, 16383, 0, 0, 32765, 16383)] // Blue, 25% Alpha
+    [InlineData(8191, 0, 0, 0, 0, 0, 0, 0)] // Red, 0% Alpha
+    [InlineData(0, 8191, 0, 0, 0, 0, 0, 0)] // Green, 0% Alpha
+    [InlineData(0, 0, 8191, 0, 0, 0, 0, 0)] // Blue, 0% Alpha
+    public void ColorFromRgba64Premultiplied_WithAlpha_ReturnExpectedValues(ushort r, ushort g, ushort b, ushort a, ushort expectedR, ushort expectedG, ushort expectedB, ushort expectedA)
+    {
+        Rgba64 actual = TiffUtilities.ColorFromRgba64Premultiplied<Rgba64>(r, g, b, a);
+
+        Assert.Equal(new Rgba64(expectedR, expectedG, expectedB, expectedA), actual);
+    }
+}
--- a/tests/ImageSharp.Tests/TestImages.cs
+++ b/tests/ImageSharp.Tests/TestImages.cs
@ -1142,6 +1142,7 @@ public static class TestImages
        public const string Issues2435 = "Tiff/Issues/Issue2435.tiff";
        public const string Issues2454_A = "Tiff/Issues/Issue2454_A.tif";
        public const string Issues2454_B = "Tiff/Issues/Issue2454_B.tif";
+        public const string Issues3031 = "Tiff/Issues/Issue3031.tiff";
        public const string Issues2587 = "Tiff/Issues/Issue2587.tiff";
        public const string Issues2679 = "Tiff/Issues/Issue2679.tiff";
        public const string JpegCompressedGray0000539558 = "Tiff/Issues/JpegCompressedGray-0000539558.tiff";
--- a/tests/Images/External/ReferenceOutput/TiffDecoderTests/TiffDecoder_CanDecode_64Bit_WithAssociatedAlpha_Rgba64_Issue3031.png
+++ b/tests/Images/External/ReferenceOutput/TiffDecoderTests/TiffDecoder_CanDecode_64Bit_WithAssociatedAlpha_Rgba64_Issue3031.png
@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:c33a2f63836975bdc7631f26634b3fb0ae98bfaff730300877339cb568141cde
+size 124
--- a/tests/Images/External/ReferenceOutput/TiffDecoderTests/TiffDecoder_CanDecode_64Bit_WithAssociatedAlpha_Rgba64_RgbaAssociatedAlpha16bit_lsb.png
+++ b/tests/Images/External/ReferenceOutput/TiffDecoderTests/TiffDecoder_CanDecode_64Bit_WithAssociatedAlpha_Rgba64_RgbaAssociatedAlpha16bit_lsb.png
@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:e50dfa103459d21642df5e1ca760081fbdfe3b7244624d9d87d8a20f45b51bbe
+size 117953
--- a/tests/Images/External/ReferenceOutput/TiffDecoderTests/TiffDecoder_CanDecode_64Bit_WithAssociatedAlpha_Rgba64_RgbaAssociatedAlpha16bit_msb.png
+++ b/tests/Images/External/ReferenceOutput/TiffDecoderTests/TiffDecoder_CanDecode_64Bit_WithAssociatedAlpha_Rgba64_RgbaAssociatedAlpha16bit_msb.png
@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:3333503012aa29e23f0d0e52993ad3499514251208fb3318e2bb1560d54650fa
+size 117956
--- a/tests/Images/External/ReferenceOutput/TiffDecoderTests/TiffDecoder_CanDecode_BigEndian_AssociatedAlpha_Rgba16161616_Rgba64_Issue3031.png
+++ b/tests/Images/External/ReferenceOutput/TiffDecoderTests/TiffDecoder_CanDecode_BigEndian_AssociatedAlpha_Rgba16161616_Rgba64_Issue3031.png
@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:c33a2f63836975bdc7631f26634b3fb0ae98bfaff730300877339cb568141cde
+size 124
--- a/tests/Images/Input/Tiff/Issues/Issue3031.tiff
+++ b/tests/Images/Input/Tiff/Issues/Issue3031.tiff
@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:6e4d2db56a1b7fdea09ed65eab1d10a02952821f6662ca77caa44b8c51b30310
+size 416