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Clone TIFF profiles into image metadata - #3159

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JimBobSquarePants merged 2 commits into
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fix/3145-preserve-tiff-icc-profile
Jul 23, 2026
Merged

Clone TIFF profiles into image metadata#3159
JimBobSquarePants merged 2 commits into
mainfrom
fix/3145-preserve-tiff-icc-profile

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Description

Fixes #3145

Update TIFF metadata creation to build ImageMetadata after IFD tag processing and copy root-frame EXIF/ICC/IPTC/XMP profiles to image scope via deep clones. This keeps image-level metadata in sync for downstream single-frame encoders while preserving independent mutability between frame and image metadata. Tests now cover preserved ICC handling and verify image-level profile presence, equality, and non-shared instances for EXIF/XMP/IPTC, including ignore-metadata behavior.

Update TIFF metadata creation to build ImageMetadata after IFD tag processing and copy root-frame EXIF/ICC/IPTC/XMP profiles to image scope via deep clones. This keeps image-level metadata in sync for downstream single-frame encoders while preserving independent mutability between frame and image metadata. Tests now cover preserved ICC handling and verify image-level profile presence, equality, and non-shared instances for EXIF/XMP/IPTC, including ignore-metadata behavior.

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Pull request overview

This PR fixes TIFF decoding so that image-level metadata (used by downstream single-frame encoders) is kept in sync with the root frame’s metadata by deep-cloning TIFF-derived profiles (EXIF/ICC/IPTC/XMP) into Image.Metadata after IFD tag processing.

Changes:

  • Create ImageMetadata after per-frame IFD tag processing so derived IPTC/XMP profiles are available before mirroring to image scope.
  • Deep-clone root-frame EXIF/ICC/IPTC/XMP profiles into Image.Metadata to preserve metadata when encoding to single-frame formats while avoiding shared mutable instances.
  • Add/extend tests to verify preserved ICC handling and that image-level profiles exist, match content, and are not the same instances as frame-level profiles (including skip-metadata behavior).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File Description
src/ImageSharp/Formats/Tiff/TiffDecoderMetadataCreator.cs Builds image-level metadata after IFD processing and deep-clones root-frame profiles to image scope.
tests/ImageSharp.Tests/Formats/Tiff/TiffMetadataTests.cs Verifies image-level EXIF/XMP/IPTC profile presence/absence and non-shared instances vs root frame (incl. skip metadata).
tests/ImageSharp.Tests/Formats/Tiff/TiffDecoderTests.cs Adds coverage ensuring ICC is preserved (and cloned) when ColorProfileHandling.Preserve is used.

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Fixes EXIF serialization when `ExifLong8Array` downgrades to `ExifDataType.Long` but still stores values as `ulong`. `ExifWriter.WriteValue` now handles `ulong` inputs in the `Long` branch by writing 32-bit values, and a BigTIFF metadata test verifies mixed in-range values are written correctly as two little-endian `uint`s.
Copilot AI review requested due to automatic review settings July 23, 2026 10:38

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Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

@JimBobSquarePants
JimBobSquarePants merged commit 776cb8b into main Jul 23, 2026
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@JimBobSquarePants
JimBobSquarePants deleted the fix/3145-preserve-tiff-icc-profile branch July 23, 2026 10:52
This was referenced Aug 17, 2026
IhateTrains added a commit to ParadoxGameConverters/ImperatorToCK3 that referenced this pull request Aug 23, 2026
Updated [SixLabors.ImageSharp](https://github.com/SixLabors/ImageSharp)
from 3.1.12 to 4.1.1.

<details>
<summary>Release notes</summary>

_Sourced from [SixLabors.ImageSharp's
releases](https://github.com/SixLabors/ImageSharp/releases)._

## 4.1.1

## What's Changed
* Fix CCITT decompressor bounds checks and error handling by
@​JimBobSquarePants in SixLabors/ImageSharp#3176


**Full Changelog**:
SixLabors/ImageSharp@v4.1.0...v4.1.1

## 4.1.0

## What's Changed
* GIF: background handling & quantizer overflow fix by
@​JimBobSquarePants in SixLabors/ImageSharp#3133
* Validate PBM max pixel value by @​JimBobSquarePants in
SixLabors/ImageSharp#3134
* Add support for Apple CgBI PNG images by @​Erik-White in
SixLabors/ImageSharp#3136
* Fix GIF transparency handling and dither by @​JimBobSquarePants in
SixLabors/ImageSharp#3143
* Bump codecov/codecov-action from 6 to 7 by @​dependabot[bot] in
SixLabors/ImageSharp#3141
* Add BlendWithCoverage overloads. Optimize Rgba32 compatible shuffling.
by @​JimBobSquarePants in
SixLabors/ImageSharp#3150
* Bump actions/checkout from 6 to 7 by @​dependabot[bot] in
SixLabors/ImageSharp#3146
* Bump actions/cache from 5 to 6 by @​dependabot[bot] in
SixLabors/ImageSharp#3149
* Fix convolution sampling for bounds smaller than the kernel radius by
@​JimBobSquarePants in SixLabors/ImageSharp#3152
* Enhance pixel formats and associated-alpha operations with
optimizations by @​JimBobSquarePants in
SixLabors/ImageSharp#3154
* Bump actions/setup-dotnet from 5 to 6 by @​dependabot[bot] in
SixLabors/ImageSharp#3155
* Fix degeneracy check for resize transforms by @​JimBobSquarePants in
SixLabors/ImageSharp#3157
* Improvements to Apple CgBI PNG handling by @​Erik-White in
SixLabors/ImageSharp#3137
* Clone TIFF profiles into image metadata by @​JimBobSquarePants in
SixLabors/ImageSharp#3159
* Add AOT compiler seeds for pixel formats and ICO, CUR, QOI codecs by
@​JimBobSquarePants in SixLabors/ImageSharp#3160
* Normalize SIMD pipelines using TensorPrimitives_ by
@​JimBobSquarePants in SixLabors/ImageSharp#3161
* Add ANI decoder support by @​Poker-sang in
SixLabors/ImageSharp#2899
* Remove AntialiasThreshold from GraphicsOptions by @​JimBobSquarePants
in SixLabors/ImageSharp#3162
* Add plus and extended pixel blend modes by @​JimBobSquarePants in
SixLabors/ImageSharp#3163
* Fix 16-bit binary PBM sample byte order by @​JimBobSquarePants in
SixLabors/ImageSharp#3164
* Make MemoryAllocator limits configurable and extensible by
@​JimBobSquarePants in SixLabors/ImageSharp#3165

## New Contributors
* @​Erik-White made their first contribution in
SixLabors/ImageSharp#3136

**Full Changelog**:
SixLabors/ImageSharp@v4.0.0...v4.1.0

## 4.0.0

## What's Changed
* Update to net8 by @​stefannikolei in
SixLabors/ImageSharp#2583
* Handle dedup of local palette of 256 length - Main by
@​JimBobSquarePants in SixLabors/ImageSharp#2607
* Replace custom Crc32 by @​JimBobSquarePants in
SixLabors/ImageSharp#2611
* Sync 3.1 DrawImage fixes by @​tocsoft in
SixLabors/ImageSharp#2612
* Fix handling gif encoding for global palettes - Main by
@​JimBobSquarePants in SixLabors/ImageSharp#2615
* Bump actions/setup-dotnet from 3 to 4 by @​dependabot[bot] in
SixLabors/ImageSharp#2613
* Adjusted the casing of the Webp format name by @​jscarle in
SixLabors/ImageSharp#2623
* Fix Paeth Filter decode on platforms that do not support Ssse3 - Main
by @​JimBobSquarePants in
SixLabors/ImageSharp#2620
* Fix WebP animation speed bug by @​marklagendijk in
SixLabors/ImageSharp#2624
* Promote PixelTypeInfo to Pixel by @​stefannikolei in
SixLabors/ImageSharp#2601
* TGA: Treat 32 bit True Color images always as transparent by
@​brianpopow in SixLabors/ImageSharp#2643
* Modernize and optimize pixel format operations across platforms. by
@​JimBobSquarePants in SixLabors/ImageSharp#2645
* Cleanup SimdUtils by @​JimBobSquarePants in
SixLabors/ImageSharp#2654
* Bump actions/cache from 3 to 4 by @​dependabot[bot] in
SixLabors/ImageSharp#2648
* Bump codecov/codecov-action from 3 to 4 by @​dependabot[bot] in
SixLabors/ImageSharp#2657
* Bump NuGet/setup-nuget from 1 to 2 by @​dependabot[bot] in
SixLabors/ImageSharp#2658
* Add v3.1.x fixes #​2673 and #​2674 into main. by @​JimBobSquarePants
in SixLabors/ImageSharp#2675
* Add fixes 2668, 2676, and 2677 to main by @​JimBobSquarePants in
SixLabors/ImageSharp#2678
* Merge 2681 to v4 Main by @​JimBobSquarePants in
SixLabors/ImageSharp#2690
* Add JPEG COM marker support by @​RobertMut in
SixLabors/ImageSharp#2641
* Bump actions/upload-artifact from 3 to 4 by @​dependabot[bot] in
SixLabors/ImageSharp#2625
* Only exit JPEG scan decoding after multiple EOF hits by
@​JimBobSquarePants in SixLabors/ImageSharp#2701
* V4 Ensure VP8X alpha flag is updated correctly. by @​JimBobSquarePants
in SixLabors/ImageSharp#2703
* Fix animated png handling (issue #​2708) by @​SpaceCheetah in
SixLabors/ImageSharp#2710
* Merge latest release from v3 by @​JimBobSquarePants in
SixLabors/ImageSharp#2720
* Fix MacOS jobs by @​antonfirsov in
SixLabors/ImageSharp#2728
* Fix async-over-sync issue in Image.DecodeAsync() by @​kroymann in
SixLabors/ImageSharp#2725
* Fix overflow in MemoryAllocator.Create(options) by @​antonfirsov in
SixLabors/ImageSharp#2730
* GifDecoder: Limit lzw bits to a maximum of 12 bits by @​brianpopow in
SixLabors/ImageSharp#2744
* GifDecoder : Allow skipping bad metadata using identify by
@​JimBobSquarePants in SixLabors/ImageSharp#2749
* Add ICO and CUR file decoder. by @​frg2089 in
SixLabors/ImageSharp#2579
* v4 - Fix off-by-one error when centering a transform. by
@​JimBobSquarePants in SixLabors/ImageSharp#2761
* v4 Fix 2758 by @​JimBobSquarePants in
SixLabors/ImageSharp#2764
* Simplify Color Space Conversion APIs by @​JimBobSquarePants in
SixLabors/ImageSharp#2739
* Webp: Fix Issue 2763 by @​brianpopow in
SixLabors/ImageSharp#2767
* V4 Correctly break during Png decoding by @​JimBobSquarePants in
SixLabors/ImageSharp#2773
* V4 : Fix filtering on PNG encode. by @​JimBobSquarePants in
SixLabors/ImageSharp#2778
* Fix #​2779 buffer overrun by @​KirillAldashkin in
SixLabors/ImageSharp#2780
* Fix ImageMetadata docs typo by @​lofcz in
SixLabors/ImageSharp#2781
* Add API for metadata conversion between formats. by
@​JimBobSquarePants in SixLabors/ImageSharp#2751
* Tiff decoder: Fix issue 2679 by @​brianpopow in
SixLabors/ImageSharp#2789
* Replace PngCrcChunkHandling by @​JimBobSquarePants in
SixLabors/ImageSharp#2786
* Add tagname to debugger visualization for Exif- and Iptc-values, to
facilitate easier debugging and discovery by @​lassevk in
SixLabors/ImageSharp#2787
* V4 - Correctly handle transform spaces when building transform
matrices. by @​JimBobSquarePants in
SixLabors/ImageSharp#2795
* Allow decoding Tiff of different frame size. by @​JimBobSquarePants in
SixLabors/ImageSharp#2788
* Add progressive JPEG encoder by @​ardabada in
SixLabors/ImageSharp#2740
* Fix using dither in BmpEncoder when bit per pixel is <= 4 by @​mistoll
in SixLabors/ImageSharp#2819
* Add QuadDistortion to ProjectiveTransformBuilder by @​Socolin in
SixLabors/ImageSharp#2748
* WEBP : Use Correct Width With AlphaDecoder by @​JimBobSquarePants in
SixLabors/ImageSharp#2823
 ... (truncated)

Commits viewable in [compare
view](SixLabors/ImageSharp@v3.1.12...v4.1.1).
</details>

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When loading a tiff with an icc profile using ColorProfileHandling.Preserve the ICC Profile is lost

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