Enable colorimetric normalization of JPEG image data during decode #2922
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JimBobSquarePants
requested review from
tocsoft,
waacton,
antonfirsov,
dlemstra,
brianpopow and
Copilot
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Pull Request Overview
Adds colorimetric normalization support for JPEG (and JPEG-compressed TIFF) data by embedding ICC-based conversions into the decoding pipeline.
- Introduces
DecoderOptions.ColorProfileHandlingto specify Preserve, Compact, or Convert behavior. - Extends grayscale and CMYK JPEG converters with
ConvertToRgbInPlaceWithIccpaths and integrates ICC removal inImageDecoder. - Renames and updates YCbCr types to
YCbCrTransform, and adjusts color-profile classes for the new workflows.
Reviewed Changes
Copilot reviewed 59 out of 59 changed files in this pull request and generated no comments.
Show a summary per file
| File | Description |
|---|---|
| src/ImageSharp/Formats/Jpeg/Components/ColorConverters/JpegColorConverter.GrayScaleVector512.cs | Add ICC-aware override and repeat grayscale channel in vectorized path |
| src/ImageSharp/Formats/Jpeg/Components/ColorConverters/JpegColorConverter.GrayScaleVector256.cs | Add ICC-aware override and repeat grayscale channel in vectorized path |
| src/ImageSharp/Formats/Jpeg/Components/ColorConverters/JpegColorConverter.GrayScaleVector128.cs | Add ICC-aware override and repeat grayscale channel in vectorized path |
| src/ImageSharp/Formats/Jpeg/Components/ColorConverters/JpegColorConverter.GrayScaleScalar.cs | Implement scalar ICC conversion with buffer packing/unpacking |
| src/ImageSharp/Formats/Jpeg/Components/ColorConverters/JpegColorConverter.CmykVector512.cs | Add ICC-aware override for CMYK vectorized converter |
| src/ImageSharp/Formats/Jpeg/Components/ColorConverters/JpegColorConverter.CmykVector256.cs | Add ICC-aware override for CMYK vectorized converter |
| src/ImageSharp/Formats/Jpeg/Components/ColorConverters/JpegColorConverter.CmykVector128.cs | Add ICC-aware override for CMYK vectorized converter |
| src/ImageSharp/Formats/Jpeg/Components/ColorConverters/JpegColorConverter.CmykScalar.cs | Implement scalar ICC conversion for CMYK |
| src/ImageSharp/Formats/ImageDecoder.cs | Invoke HandleIccProfile after decode/identify to strip profiles |
| src/ImageSharp/Formats/DecoderOptions.cs | Expose ColorProfileHandling and add profile‐selection helpers |
| src/ImageSharp/Formats/ColorProfileHandling.cs | Define Compact and update docs for enum |
| src/ImageSharp/ColorProfiles/YccK.cs | Rename matrix references to YCbCrTransform |
| src/ImageSharp/ColorProfiles/YCbCrTransform.cs | Rename YCbCrMatrix to YCbCrTransform and update ctor/docs |
| src/ImageSharp/ColorProfiles/YCbCr.cs | Update property references to YCbCrTransform |
| src/ImageSharp/ColorProfiles/Y.cs | Update transform references for Y channel |
| src/ImageSharp/ColorProfiles/Rgb.cs | Replace ToScaledVector3 calls with AsVector3Unsafe |
| src/ImageSharp/ColorProfiles/KnownYCbCrMatrices.cs | Rename constants to YCbCrTransform |
| src/ImageSharp/ColorProfiles/Icc/CompactSrgbV4Profile.cs | Rename class to CompactSrgbV4Profile and adjust namespace |
| src/ImageSharp/ColorProfiles/ColorConversionOptions.cs | Change YCbCrMatrix property to YCbCrTransform |
| src/ImageSharp/Advanced/AotCompilerTools.cs | Update AOT stubs to match new GetPixelBuffer signatures |
Comments suppressed due to low confidence (5)
src/ImageSharp/ColorProfiles/ColorConversionOptions.cs:55
- Update this XML summary to reflect the renamed property (
YCbCrTransform) and its semantics (e.g., "Gets the YCbCr transform used to perform conversions...").
/// Gets the YCbCr matrix to used to perform conversions from/to RGB.
src/ImageSharp/Formats/Jpeg/Components/ColorConverters/JpegColorConverter.GrayScaleVector512.cs:22
- The
Configurationtype isn’t imported in this file, causing a compilation error; addusing SixLabors.ImageSharp;at the top so thatConfigurationis recognized.
public override void ConvertToRgbInPlaceWithIcc(Configuration configuration, in ComponentValues values, IccProfile profile)
src/ImageSharp/Formats/ImageDecoder.cs:325
- [nitpick] This logic is duplicated in two overloads; consider consolidating into a single generic or helper method to reduce code duplication.
private static void HandleIccProfile(DecoderOptions options, Image image)
src/ImageSharp/Formats/Jpeg/Components/ColorConverters/JpegColorConverter.GrayScaleScalar.cs:54
- Allocating a new buffer for every decode may impact performance; consider reusing pooled buffers or using stackalloc for small images to reduce allocation overhead.
using IMemoryOwner<float> memoryOwner = configuration.MemoryAllocator.Allocate<float>(values.Component0.Length * 3);
src/ImageSharp/Formats/DecoderOptions.cs:72
- The out parameter
valueis overly generic and nullable despite theNotNullWhen(true)annotation; rename it to a descriptive name (e.g.out IccProfile profileToConvert) and consider making it non-nullable when returned true.
internal bool TryGetIccProfileForColorConversion(IccProfile? profile, [NotNullWhen(true)] out IccProfile? value)
|
(Sorry, misclicking!) Happy to take a look but will be in a couple of weeks after my break |
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Prerequisites
Description
This PR adds support for normalizing color data in JPEG files (and TIFF files with JPEG compression) to sRGB during decoding.
A new
DecoderOptions.ColorProfileHandlingproperty controls this behavior with the following options:Several internal helper methods have been introduced to allow decoders to determine and apply the correct behavior.
All shared JPEG color converters now use a common scalar interleaving path to manipulate planar data for
ColorProfileConverter. There's likely room for SIMD-based performance improvements here (AVX-512?).@waacton - might be of interest to you since it introduces questions around deriving RGB working spaces from ICC profiles which you are likely to better understand than I.
@saucecontrol - tagging you since your compact sRGB v4 profile implementation was invaluable (and shamelessly borrowed 😁).