add support for extra channels

[chrstphrbrns]

Fixes #100

Exports three new functions

• color -- extract the color component of an image, eg

julia> imshow(color(im));

• nchannels -- get the total number of channels from an image (color channels + extra channels)
• channel -- get the values from a specific channel (with the first N channels being color channels), eg

julia> imshow(channel(im, 5));

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 87.87879% with 12 lines in your changes missing coverage. Please review.

Project coverage is 92.36%. Comparing base (25cf338) to head (31eaaa3).

Files with missing lines	Patch %	Lines
src/types/common.jl	85.71%	5 Missing ⚠️
src/types/widepixel.jl	28.57%	5 Missing ⚠️
src/load.jl	87.50%	1 Missing ⚠️
src/types/lazy.jl	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #159      +/-   ##
==========================================
- Coverage   92.68%   92.36%   -0.33%     
==========================================
  Files          13       14       +1     
  Lines        1121     1152      +31     
==========================================
+ Hits         1039     1064      +25     
- Misses         82       88       +6     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[tlnagy]

This looks fantastic! Just a couple smaller points.

[tlnagy]

This is basically ready to merge, I think only the test for #56 is missing.

[kimikage]

This is just a comment and does not block the merge, but color is one of the functions that ColorTypes exports.
TiffImages users are likely to be using ColorTypes, Colors, or Images.
At the very least, it would be good to have a note in the document.

[chrstphrbrns]

This is just a comment and does not block the merge, but color is one of the functions that ColorTypes exports. TiffImages users are likely to be using ColorTypes, Colors, or Images. At the very least, it would be good to have a note in the document.

What kind of a note? Julia already warns when two packages export the same symbol

WARNING: both ColorTypes and TiffImages export "color"; uses of it in module Main must be qualified

[kimikage]

It is not what it is, but where it is that matters.

in the document.

[tlnagy]

Sorry for the delay here, I was on vacation. I'm happy with the state of this PR (thanks @chrstphrbrns for your hard work here!). I'm going to release #165 as v0.10.1 and then I'll merge this PR into master to be released as v0.11.0.

[juliohm]

@tlnagy any update regarding this amazing PR by @chrstphrbrns ?

[juliohm]

It would be really useful to have this feature in place to solve #100

@tlnagy what is your plan regarding this PR?

[tlnagy]

Sorry, I've been swamped at my new job and haven't had much time for my Julia packages. I just released v0.10.1 and I'll release #165 as v0.10.2, rebase this branch, and if it all passes, this'll come out as v0.11.0

[tlnagy]

The segmentation fault with Julia nightly on MacOS + Arm64 is concerning. @chrstphrbrns any idea why SIMD might be failing there?

[juliohm]

@tlnagy is the failure on Julia nightly blocking? We are really looking forward to this.

[eliascarv]

@tlnagy, reading the error stack trace, we can see that the error is coming from the SIMD.jl package:

Reading the TiffImages.jl code, I noticed that the deplane! and recode functions use SIMD.jl, these are used by the read! function, which is used by the load function.

The SIMD.jl package uses internal Julia APIs, which may change between versions. This is why we may notice that SIMD.jl tests break in Julia nightly:

So I think we can conclude that the errors in the tests are related to the SIMD.jl package, not the PR. Do you agree?

Maybe tests should only be run on stable Julia versions?

[eliascarv]

And about the test that is breaking on Ubuntu with Julia 1.11, I ran the PR tests locally on my machine with Fedora and Julia 1.11.1 and the tests passed normally:

Version info:

Julia Version 1.11.1
Commit 8f5b7ca12ad (2024-10-16 10:53 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: 12 × Intel(R) Core(TM) i5-10400 CPU @ 2.90GHz
  WORD_SIZE: 64
  LLVM: libLLVM-16.0.6 (ORCJIT, skylake)
Threads: 1 default, 0 interactive, 1 GC (on 12 virtual cores)

[tlnagy]

Maybe tests should only be run on stable Julia versions?

This a good point. I was mostly concerned about it failing on M series chips, but yeah it should only be blocking on stable Julia.

[tlnagy]

And about the test that is breaking on Ubuntu with Julia 1.11, I ran the PR tests locally on my machine with Fedora and Julia 1.11.1 and the tests passed normally:

The failure is on 32 bit systems so it's likely related to #169 and #170 so it shouldn't hold anything up.

[tlnagy]

Huge thanks for @chrstphrbrns for all the work getting this done and @juliohm for consistently advocating for it. Excited to have this in TiffImages v0.11.0

[juliohm]

Thank you @tlnagy for making it happen! Do you have a date for the new v0.11 release? We are looking forward to it.