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Add support for OpenEXR image format#3096

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brianpopow wants to merge 75 commits intomainfrom
bp/openExr
Open

Add support for OpenEXR image format#3096
brianpopow wants to merge 75 commits intomainfrom
bp/openExr

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@brianpopow brianpopow commented Mar 29, 2026 •
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Prerequisites

  • I have written a descriptive pull-request title
  • I have verified that there are no overlapping pull-requests open
  • I have verified that I am following the existing coding patterns and practice as demonstrated in the repository. These follow strict Stylecop rules 👮.
  • I have provided test coverage for my change (where applicable)

Description

This PR adds support for decoding and encoding of images in the OpenEXR format. OpenEXR is a HDR image format, therefore I have added two new pixel formats Rgb96 and Rgba128 which store each color channel as UInt32.

The specification can be found here: https://openexr.com/en/latest/index.html#openexr

A reference implementation can be found here: https://github.com/AcademySoftwareFoundation/openexr.git

@brianpopow
Parse open EXR header
9dda678
@brianpopow
Decode uncompressed EXR images with 16 bit pixel data for each channel
a27696a
@brianpopow
Decode EXR images with 32 bit float pixel data
d3993f7
@brianpopow
Decode EXR images with unsigned int pixel data
aaf2143
@brianpopow
Encode EXR image with float pixel data
799dafe
@brianpopow
Encode EXR image with HalfSingle pixel data
4cf95a5
@brianpopow
Encode EXR image with usigned int pixel data
7e7472d
@brianpopow
Update tests for EXR images
652b385
@brianpopow
Add support for decoding EXR images with alpha channel
70cfcc9
@brianpopow
Add support for decoding exr with zips compression
3279762
@brianpopow
Add support for decoding RLE exr images
85501f3
@brianpopow
Add support for ZIP compressed exr images
69c8cd8
@brianpopow
Add support for decoding gray exr images
fdc7b61
@brianpopow
Refactor
fd0c245
@brianpopow
Merge remote-tracking branch 'origin/main' into bp/openExr
88a06e8 
# Conflicts:
#	src/ImageSharp/Configuration.cs
@brianpopow
Merge remote-tracking branch 'origin/main' into bp/openExr
aabe561 
# Conflicts:
#	src/ImageSharp/Formats/Bmp/BmpConstants.cs
#	src/ImageSharp/Formats/Bmp/BmpDecoder.cs
#	src/ImageSharp/Formats/Bmp/BmpFormat.cs
@brianpopow
Merge remote-tracking branch 'origin/main' into bp/openExr
440408b 
# Conflicts:
#	src/ImageSharp/Configuration.cs
#	src/ImageSharp/Formats/Bmp/BmpArrayFileHeader.cs
#	src/ImageSharp/Formats/Bmp/BmpConstants.cs
#	src/ImageSharp/Formats/Bmp/BmpFormat.cs
#	src/ImageSharp/Formats/Bmp/BmpImageFormatDetector.cs
#	src/ImageSharp/Formats/ImageExtensions.Save.cs
#	src/ImageSharp/Formats/Pbm/BufferedReadStreamExtensions.cs
#	tests/ImageSharp.Tests/ConfigurationTests.cs
#	tests/ImageSharp.Tests/Formats/GeneralFormatTests.cs
@brianpopow
Fix build errors
ea1aaa7
@brianpopow
Add exr decoder tests
ce21f1a
@brianpopow
Add support for decoding b44 compressed exr files
a9620ee
@brianpopow
Fix warnings
ec8163a
@brianpopow
Add DecodeTiledFloatingPointPixelData
28dcdf2
@brianpopow
Merge remote-tracking branch 'origin/main' into bp/openExr
94cd5b0 
# Conflicts:
#	src/ImageSharp/Configuration.cs
#	src/ImageSharp/Formats/Bmp/BmpArrayFileHeader.cs
#	src/ImageSharp/Formats/Bmp/BmpConstants.cs
#	src/ImageSharp/Formats/Bmp/BmpDecoder.cs
#	src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs
#	src/ImageSharp/Formats/Bmp/BmpFileHeader.cs
#	src/ImageSharp/Formats/Bmp/BmpFormat.cs
#	src/ImageSharp/Formats/Bmp/BmpImageFormatDetector.cs
#	src/ImageSharp/Formats/Bmp/BmpInfoHeader.cs
#	src/ImageSharp/Formats/ImageDecoderUtilities.cs
#	src/ImageSharp/Formats/ImageExtensions.Save.cs
#	src/ImageSharp/Formats/Pbm/BufferedReadStreamExtensions.cs
#	src/ImageSharp/Image.Decode.cs
#	tests/ImageSharp.Tests/ConfigurationTests.cs
#	tests/ImageSharp.Tests/Formats/GeneralFormatTests.cs
@brianpopow
Merge remote-tracking branch 'origin/bp/openExr' into bp/openExr
d0d5e86 
# Conflicts:
#	src/ImageSharp/Formats/Bmp/BmpFormat.cs
#	src/ImageSharp/Formats/ImageDecoderUtilities.cs
#	src/ImageSharp/Formats/ImageExtensions.Save.cs
#	src/ImageSharp/Formats/OpenExr/ExrDecoderCore.cs
@brianpopow
Merge branch 'main' into bp/openExr
7748467 
# Conflicts:
#	src/ImageSharp/Configuration.cs
#	src/ImageSharp/Formats/ImageDecoderUtilities.cs
#	tests/ImageSharp.Tests/TestUtilities/TestEnvironment.Formats.cs
@brianpopow
Adjust exr decoder / encoder to ImageSharp changes
fa52ab7
@brianpopow
Change exr name space to SixLabors.ImageSharp.Formats.Exr
83dba58
@brianpopow
Fix issue in ExrImageFormatDetector.cs returning wrong format
b78402d
@brianpopow
Use MagickReference decoder for exr decoding tests
faf87fb
@brianpopow
Fix issue assigning pixel value from HalfVector4
eaea042
brianpopow added 15 commits March 26, 2026 17:35
@brianpopow
Implement missing Rgb96 methods
6a92b0c
@brianpopow
Implement missing methods for Rgba128
355d1bc
@brianpopow
Use cancellation token, when decoding exr images
c0e3d28
@brianpopow
Use cancellation token when encoding exr images
3e7ef68
@brianpopow
Add benchmark for decoding exr image
d29fe89
@brianpopow
Update Magick.NET-Q16 to version 14.11.1 for fix to decoding zip comp…
9ead3eb 
…ressed exr files
@brianpopow
Use CompareToReferenceOutput for int pixel type
aa0af92
@brianpopow
Use tolerant comparer for B44 compression
53230af
@brianpopow
Use exact comparer as default for exr decoder tests
a741e84
@brianpopow
Set exr pixel type when decoding an image
8c0c854
@brianpopow
Implement GetPixelTypeInfo() for EXR
c8c3656
@brianpopow
Add tests for exr metadata
b956634
@brianpopow
Add compression to exr metadata
a9f6dbc
@brianpopow
Throw InvalidImageContentException when requiered header fields are m…
7939cc9 
…issing
@brianpopow
Add some more comments
a1152c5
@brianpopow brianpopow added the formats:exr Any PR or issue related to OpenExr file format label Mar 29, 2026
github-code-quality[bot]
github-code-quality bot found potential problems Mar 29, 2026
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github-code-quality[bot]
github-code-quality bot found potential problems Mar 30, 2026
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github-code-quality[bot]
github-code-quality bot found potential problems Mar 30, 2026
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JimBobSquarePants commented Mar 31, 2026

@brianpopow I'll review this asap.

antonfirsov
antonfirsov reviewed Mar 31, 2026
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src/ImageSharp/Common/Helpers/ColorNumerics.cs
/// <param name="component">The 32 bit component value.</param>
/// <returns>The <see cref="byte"/> value.</returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static byte From32BitTo8Bit(uint component) => (byte)(component * Scale32Bit);
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@antonfirsov antonfirsov Mar 31, 2026 •
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Perf is maybe not a primary concern at this point but I wonder if there is a cheaper way to correctly calculate this that avoids FP conversion? How does the reference implementation calculate this (if they care about decoding into lower res format)?

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@antonfirsov antonfirsov Apr 4, 2026 •
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@brianpopow actually, I don't understand this. From32BitTo8Bit(uint.MaxValue) == 1. Are you sure this logic is correct? If it's incorrect, I wonder why tests didn't catch it? Wouldn't (byte)(component >> 16) do the job?

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@brianpopow brianpopow Apr 4, 2026

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@antonfirsov Yes I think you are right, this does not look right.

I wonder why tests didn't catch it?

There are no pixel conversion tests yet for the new pixel types. I will try to add tests for the new pixlel types Rgb96 and Rgba128 next.

Wouldn't (byte)(component >> 16) do the job?

Yeah that's more like it, but I think it should be (byte)(component >> 24)? Lets say we have for example Int.Max / 2, e.g. 2147483647. Converting this to 8 bit should be 127.

antonfirsov
antonfirsov reviewed Mar 31, 2026
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@antonfirsov antonfirsov left a comment •
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Couple of places where the return value from stream.Read(...) is not checked. I may have missed some, it is worth a comprehensive check.

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