Add full BigTiff open/export support to GIMP
Recently I've been using Hugin to make panoramas and then edit them in GIMP, which worked very nicely until I tried to export a 32-bit floating point tiff that was larger than 4GB, at which point a GIMP pop-up announced:
Maximum TIFF file size exceeded
Failed a scanline write on row 18688
A search on the internet turned up this bug report which was opened 7 years ago and closed a year ago: file-tiff-load crashes if I try to open a BigTIFF file: #645 (closed)
A lot of photographers currently produce high resolution panoramic images, where the length by width of the assembled image is considerably larger than that of the camera used to capture the individual frames, for example:
- https://www.lonelyspeck.com/how-to-shoot-large-format-astrophotography-panoramas/
- https://www.chasejarvis.com/blog/size-matters-how-to-build-a-272-gigapixel-panorama/
- https://www.youtube.com/results?search_query=panoramic+photography
- https://en.wikipedia.org/wiki/Gigapixel_image
- http://www.gigamacro.com/worlds-first-terapixel-macro-image/
Here is Wikipedia's comment on BigTIFF (https://en.wikipedia.org/wiki/TIFF#BigTIFF):
"The TIFF file formats use 32-bit offsets, which limits file size to around 4 GiB. Some implementations even use a signed 32-bit offset, running into issues around 2 GiB. BigTIFF is a TIFF variant file format which uses 64-bit offsets and supports much larger files (up to 18 exabytes in size).[30] The BigTIFF file format specification was implemented in 2007 in development releases of LibTIFF version 4.0, which was finally released as stable in December 2011. Support for BigTIFF file formats by applications is limited."
A short internet search brought up the following softwares that do support BigTIFF:
- BigTIFF support was completed in libtiff in 2009 (commit e7ccb79ae3b5dd68366c8a2f50b5a06fbcbe01e3). The last BigTIFF commit was in 2019 and there are no outstanding bug reports, so it seems BigTiff must be working pretty well.
- GraphicsMagick and so presumably ImageMagick added BigTIFF support in 2008: http://www.graphicsmagick.org/NEWS.html
- LibVips and g'mic (support added in 2017) support bigtiff. Also PhotoFlow supports opening/editing/exporting BigTIFF as it uses libvips (tested in PF, it works).
https://www.loc.gov/preservation/digital/formats/fdd/fdd000328.shtml provides a list of various softwares that support BigTIFF, including large format scanners, geographical information storage files, medical imaging, and various very large image viewers.
See this post from a potential GIMP user wanting to work with BigTIFF bio-images: https://discuss.pixls.us/t/dealing-with-bigtiff-files-open-edit-save-etc/11592
Given that GIMP is a 32-bit floating point photographic image editor - that also aims to support scientific editing - it would be very beneficial if GIMP could open, edit, and save BigTIFF files.