Fix overlay conversions

[jenshannoschwalm]

We don't want to do any colorspace conversion in the overlayed image.

Thus we

• include colorin module in the "module filter out" list
• we don't enforce colorin via it's commit_params if we develop with finalscale enabled.

See #17060

@TurboGit not completely sure about this yet thus WIP.

[TurboGit]

Today I had a need to use the composite module, and the color was bad. I then tried the demo I had posted on the PR when working on this, and the color was bad. I remembered about this PR, testing it and all was back to normal.

What I don't understand is that this was working when release 4.8 was done since I tested it... What could have been broken this since then... Really puzzling ! But for sure this PR is correct to me. Will double check later.

[jenshannoschwalm]

I think we had this wrong also in 4.8 ...

[TurboGit]

I think we had this wrong also in 4.8 ...

Agreed, but it was ok at some point as I had tested and published examples using this module in the PR. See for example:

#15465 (comment)

#15465 (comment)

In original module (first implementation), commit fca903e:

+    if((disable
+        && !dt_iop_module_is(mod->so, "gamma"))
+       || (is_current
+           && (dt_iop_module_is(mod->so, "enlargecanvas")
+               || dt_iop_module_is(mod->so, "overlay")
+               || dt_iop_module_is(mod->so, "crop")
+               || dt_iop_module_is(mod->so, "flip")
+               || dt_iop_module_is(mod->so, "ashift"))))
+    {
+      result = g_list_prepend(result, mod->op);
+    }

But is was add on Jun 16th in commit a775869 by you.

I probably didn't test properly this change or at least didn't pay attention to the color shift. Really too bad that I missed that :(

[TurboGit]

Obviously correct and corresponding to the initial implementation of overlay module.

[jenshannoschwalm]

Indeed i introduced that issue, sorry about that and about me not pushing harder on this pr :-(

[TurboGit]

@jenshannoschwalm : That's also my fault, so not problem. The good news is that I have added two tests for the overlay module (only self referencing overlay for the testsuite).