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Add support for decoding tiff's with 32bit float rgb pixel data
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9 files changed

+142
-5
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‎src/ImageSharp/Formats/Tiff/PhotometricInterpretation/RgbFloat323232TiffColor{TPixel}.cs‎

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// Copyright (c) Six Labors.
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// Licensed under the Apache License, Version 2.0.
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using System;
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using System.Numerics;
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using SixLabors.ImageSharp.Formats.Tiff.Utils;
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using SixLabors.ImageSharp.Memory;
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using SixLabors.ImageSharp.PixelFormats;
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namespace SixLabors.ImageSharp.Formats.Tiff.PhotometricInterpretation
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{
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/// <summary>
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/// Implements the 'RGB' photometric interpretation with 32 bits for each channel.
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/// </summary>
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internal class RgbFloat323232TiffColor<TPixel> : TiffBaseColorDecoder<TPixel>
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where TPixel : unmanaged, IPixel<TPixel>
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{
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private readonly bool isBigEndian;
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/// <summary>
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/// Initializes a new instance of the <see cref="RgbFloat323232TiffColor{TPixel}" /> class.
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/// </summary>
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/// <param name="isBigEndian">if set to <c>true</c> decodes the pixel data as big endian, otherwise as little endian.</param>
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public RgbFloat323232TiffColor(bool isBigEndian) => this.isBigEndian = isBigEndian;
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/// <inheritdoc/>
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public override void Decode(ReadOnlySpan<byte> data, Buffer2D<TPixel> pixels, int left, int top, int width, int height)
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{
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// Note: due to an issue with netcore 2.1 and default values and unpredictable behavior with those,
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// we define our own defaults as a workaround. See: https://github.com/dotnet/runtime/issues/55623
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var color = default(TPixel);
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color.FromVector4(TiffUtils.Vector4Default);
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int offset = 0;
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byte[] buffer = new byte[4];
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for (int y = top; y < top + height; y++)
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{
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Span<TPixel> pixelRow = pixels.GetRowSpan(y).Slice(left, width);
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if (this.isBigEndian)
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{
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for (int x = 0; x < pixelRow.Length; x++)
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{
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data.Slice(offset, 4).CopyTo(buffer);
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Array.Reverse(buffer);
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float r = BitConverter.ToSingle(buffer, 0);
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offset += 4;
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data.Slice(offset, 4).CopyTo(buffer);
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Array.Reverse(buffer);
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float g = BitConverter.ToSingle(buffer, 0);
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offset += 4;
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data.Slice(offset, 4).CopyTo(buffer);
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Array.Reverse(buffer);
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float b = BitConverter.ToSingle(buffer, 0);
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offset += 4;
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var colorVector = new Vector4(r, g, b, 1.0f);
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Array.Reverse(buffer);
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color.FromVector4(colorVector);
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pixelRow[x] = color;
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}
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}
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else
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{
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for (int x = 0; x < pixelRow.Length; x++)
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{
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data.Slice(offset, 4).CopyTo(buffer);
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float r = BitConverter.ToSingle(buffer, 0);
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offset += 4;
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data.Slice(offset, 4).CopyTo(buffer);
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float g = BitConverter.ToSingle(buffer, 0);
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offset += 4;
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data.Slice(offset, 4).CopyTo(buffer);
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float b = BitConverter.ToSingle(buffer, 0);
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offset += 4;
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var colorVector = new Vector4(r, g, b, 1.0f);
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color.FromVector4(colorVector);
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pixelRow[x] = color;
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}
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}
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}
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}
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}
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}

‎src/ImageSharp/Formats/Tiff/PhotometricInterpretation/TiffColorDecoderFactory{TPixel}.cs‎

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DebugGuard.IsTrue(colorMap == null, "colorMap");
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return new Rgb323232TiffColor<TPixel>(isBigEndian: byteOrder == ByteOrder.BigEndian);
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case TiffColorType.RgbFloat323232:
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DebugGuard.IsTrue(
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bitsPerSample.Channels == 3
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&& bitsPerSample.Channel2 == 32
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&& bitsPerSample.Channel1 == 32
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&& bitsPerSample.Channel0 == 32,
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"bitsPerSample");
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DebugGuard.IsTrue(colorMap == null, "colorMap");
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return new RgbFloat323232TiffColor<TPixel>(isBigEndian: byteOrder == ByteOrder.BigEndian);
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case TiffColorType.PaletteColor:
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DebugGuard.NotNull(colorMap, "colorMap");
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return new PaletteTiffColor<TPixel>(bitsPerSample, colorMap);

‎src/ImageSharp/Formats/Tiff/PhotometricInterpretation/TiffColorType.cs‎

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@@ -133,6 +133,11 @@ internal enum TiffColorType
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/// </summary>
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Rgb323232,
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/// <summary>
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/// RGB color image with 32 bits floats for each channel.
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/// </summary>
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RgbFloat323232,
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/// <summary>
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/// RGB Full Color. Planar configuration of data. 8 Bit per color channel.
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/// </summary>

‎src/ImageSharp/Formats/Tiff/TiffDecoderCore.cs‎

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@@ -95,6 +95,11 @@ public TiffDecoderCore(Configuration configuration, ITiffDecoderOptions options)
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/// </summary>
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public TiffPhotometricInterpretation PhotometricInterpretation { get; set; }
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/// <summary>
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/// Gets or sets the sample format.
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/// </summary>
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public TiffSampleFormat SampleFormat { get; set; }
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/// <summary>
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/// Gets or sets the horizontal predictor.
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/// </summary>

‎src/ImageSharp/Formats/Tiff/TiffDecoderOptionsParser.cs‎

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@@ -45,14 +45,16 @@ public static void VerifyAndParse(this TiffDecoderCore options, ExifProfile exif
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TiffThrowHelper.ThrowNotSupported("TIFF images with FloatingPoint horizontal predictor are not supported.");
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}
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TiffSampleFormat[] sampleFormat = exifProfile.GetValue(ExifTag.SampleFormat)?.Value?.Select(a => (TiffSampleFormat)a).ToArray();
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if (sampleFormat != null)
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TiffSampleFormat[] sampleFormats = exifProfile.GetValue(ExifTag.SampleFormat)?.Value?.Select(a => (TiffSampleFormat)a).ToArray();
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TiffSampleFormat? sampleFormat = null;
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if (sampleFormats != null)
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{
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foreach (TiffSampleFormat format in sampleFormat)
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sampleFormat = sampleFormats[0];
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foreach (TiffSampleFormat format in sampleFormats)
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{
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if (format != TiffSampleFormat.UnsignedInteger)
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if (format != TiffSampleFormat.UnsignedInteger && format != TiffSampleFormat.Float)
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{
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TiffThrowHelper.ThrowNotSupported("ImageSharp only supports the UnsignedInteger SampleFormat.");
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TiffThrowHelper.ThrowNotSupported("ImageSharp only supports the UnsignedInteger and Float SampleFormat.");
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}
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}
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}
@@ -67,6 +69,7 @@ public static void VerifyAndParse(this TiffDecoderCore options, ExifProfile exif
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options.PlanarConfiguration = (TiffPlanarConfiguration?)exifProfile.GetValue(ExifTag.PlanarConfiguration)?.Value ?? DefaultPlanarConfiguration;
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options.Predictor = frameMetadata.Predictor ?? TiffPredictor.None;
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options.PhotometricInterpretation = frameMetadata.PhotometricInterpretation ?? TiffPhotometricInterpretation.Rgb;
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options.SampleFormat = sampleFormat ?? TiffSampleFormat.UnsignedInteger;
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options.BitsPerPixel = frameMetadata.BitsPerPixel != null ? (int)frameMetadata.BitsPerPixel.Value : (int)TiffBitsPerPixel.Bit24;
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options.BitsPerSample = frameMetadata.BitsPerSample ?? new TiffBitsPerSample(0, 0, 0);
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@@ -231,6 +234,12 @@ private static void ParseColorType(this TiffDecoderCore options, ExifProfile exi
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TiffThrowHelper.ThrowNotSupported("Only BitsPerSample with equal bits per channel are supported.");
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}
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if (options.SampleFormat == TiffSampleFormat.Float)
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{
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options.ColorType = TiffColorType.RgbFloat323232;
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return;
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}
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if (options.PlanarConfiguration == TiffPlanarConfiguration.Chunky)
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{
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ushort bitsPerChannel = options.BitsPerSample.Channel0;

‎tests/ImageSharp.Tests/Formats/Tiff/TiffDecoderTests.cs‎

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image.DebugSave(provider);
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}
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[Theory]
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[WithFile(FlowerRgbFloat323232, PixelTypes.Rgba32)]
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[WithFile(FlowerRgbFloat323232LittleEndian, PixelTypes.Rgba32)]
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public void TiffDecoder_CanDecode_Float_96Bit<TPixel>(TestImageProvider<TPixel> provider)
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where TPixel : unmanaged, IPixel<TPixel>
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{
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// Note: because the MagickReferenceDecoder fails to load the image, we only debug save them.
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using Image<TPixel> image = provider.GetImage();
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image.DebugSave(provider);
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}
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[Theory]
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[WithFile(GrayscaleDeflateMultistrip, PixelTypes.Rgba32)]
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[WithFile(RgbDeflateMultistrip, PixelTypes.Rgba32)]

‎tests/ImageSharp.Tests/TestImages.cs‎

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public const string RgbPalette = "Tiff/rgb_palette.tiff";
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public const string Rgb4BitPalette = "Tiff/bike_colorpalette_4bit.tiff";
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public const string RgbPaletteDeflate = "Tiff/rgb_palette_deflate.tiff";
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public const string FlowerRgbFloat323232 = "Tiff/flower-rgb-float32_msb.tiff";
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public const string FlowerRgbFloat323232LittleEndian = "Tiff/flower-rgb-float32_lsb.tiff";
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public const string FlowerRgb323232Contiguous = "Tiff/flower-rgb-contig-32.tiff";
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public const string FlowerRgb323232ContiguousLittleEndian = "Tiff/flower-rgb-contig-32_lsb.tiff";
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public const string FlowerRgb323232Planar = "Tiff/flower-rgb-planar-32.tiff";

‎tests/Images/Input/Tiff/flower-rgb-float32_lsb.tiff‎

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version https://git-lfs.github.com/spec/v1
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oid sha256:a1f889baa6f3bb99f15609848cdd47d548d3e2ed1b7b558d428550dfa3bd4bf9
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size 38050

‎tests/Images/Input/Tiff/flower-rgb-float32_msb.tiff‎

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version https://git-lfs.github.com/spec/v1
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oid sha256:2c02be5dff2bcd5d60afbf379ba9095b0c8fd3a7a0063f684ac9ac9119f967a5
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size 38050

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