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GD strips the ICC colour profile when loading an image but keeps the pixel values, so previews of wide-gamut photos (Display P3, Adobe RGB) are served as untagged JPEGs that browsers render as sRGB, looking washed out compared to the original. Remember the source profile in OC\Image, carry it across the resize and crop copies the preview generator uses, and re-embed it into the encoded JPEG (APP2) or PNG (iCCP) output. No colour conversion is done: the pixels already match the profile, they were only mistagged. Only RGB profiles are kept, since GD converts CMYK and grayscale sources to RGB. Also re-attach the profile in the HEIC provider after stripImage() removes it from small thumbnails. Closes #22951 Assisted-by: ClaudeCode:claude-opus-4-8 Signed-off-by: Mattias Svensson <mattias.m.svensson@gmail.com>
The colour profile fixtures embedded profiles copyrighted by Apple with all rights reserved and were annotated as 2013 ownCloud images. Regenerate them as synthetic gradients tagged with the CC0 Display P3 and CGATS001 CMYK profiles from Compact-ICC-Profiles, annotate them separately and add a PNG fixture to cover reading the iCCP chunk. Assisted-by: ClaudeCode:claude-opus-5-5 Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>
The iCCP chunk of a PNG was inflated without a limit, so a few hundred KiB of compressed zeros made a single preview request allocate hundreds of MiB and run into the memory limit. Cap profiles at 64 KiB, which is far above real display profiles: bound the decompression, stop collecting JPEG APP2 chunks beyond it and only accept profiles whose declared size matches their actual size. Assisted-by: ClaudeCode:claude-opus-5-5 Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>
Many cameras and photo editors tag their output with an sRGB profile. Untagged images are displayed as sRGB anyway, so carrying that profile only grows every preview: the common 3 KiB sRGB IEC61966-2.1 profile quadruples a 64px thumbnail. Detect sRGB by its colorants and tone curve instead of the profile name, which varies between vendors, so linear or otherwise differently encoded profiles with sRGB primaries are still preserved. Assisted-by: ClaudeCode:claude-opus-5-5 Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>
loadFromFile() read up to 8 MiB of every JPEG and PNG a second time just to find the colour profile, and missed profiles behind larger metadata. Parse the segment and chunk headers through a reader closure instead, backed by fseek()/fread() for files, so only the headers and the profile itself are read. Assisted-by: ClaudeCode:claude-opus-5-5 Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>
Imaginary is asked to strip metadata so that EXIF data like the location does not leak into previews, but libvips drops the colour profile along with it and does not convert the pixels. Wide gamut JPEG and PNG previews generated by Imaginary therefore still looked washed out. Read the profile from the head of the source that is already read for the orientation check and splice it into the encoded response. For that the profile handling of OC\Image is exposed as static helpers. Assisted-by: ClaudeCode:claude-opus-5-5 Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>
The helpers searched the whole file for the ICC markers, which can also occur inside compressed image data, and did not notice malformed output. Walk the segment and chunk structure instead and verify the iCCP CRC. Assisted-by: ClaudeCode:claude-opus-5-5 Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>
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October 30, 2026 11:53
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3. to review, feature component)stable32)AI (if applicable)