Gap Check Improvements

[blurymind]

Status Check
issues with the Gap Check include:

• Line Thickness
• Setting the Distance for the Gap Check to use (via Tape Tool options). What might not be obvious to users is that the Distance setting of the Tape Tool is what controls Gap Check line display. So for anyone that can't get Gap Check to work adjust that setting. Note that the setting is grayed out (i.e. unavailable) until specific other options of the Tape Tool are turned on/off.
• Color
• Accuracy / False positives

Currently gap check lines have a number of problems:

1. They are too thick, so they actually get in the way of visibility:
   
2. They become black when you enable fill check - considering that you will most probably have gap and fill check enabled together, and that your lineart is likely going to be black - the black color on these lines is not helpful here.
3. Gap check lines are dependent on the camera zoom - gap check lines thickness should not be dependent on zoom level - it should always be one value.
4. Lines with Zero opacity are not shown during fill check - it would be useful to have them visible (dash lines?) during fill check
5. There is no way to adjust the maximum gap distance and the current maximum distance is too great- so gap check actually draws a lot of false lines that make it harder to find where actual gaps are

-We need a way to control gap check line thickness, or have that thickness set to 2 pixels - and have it independent from zoom level
-We need gap check lines to keep their color (magenta) when fill check is enabled.

• It would help if gap check lines have a dashed styling or are 50% transparent - that way it will be easier to see the actual linework behind them.

Here I made a mockup

---

Want to back this issue? Post a bounty on it! We accept bounties via Bountysource.

[blurymind]

Very often gap check draws a gap line where there is no gap:

Why does it do that?
It makes it almost pointless to use for finding gaps. Too many wrong gap lines.
And its impossible to see which ones are the wrong ones - because the gap lines are way too thick and they get in the way of seeing the gaps too much

[gab3d]

Currently (as of last nightly build) Gap Check lines are hardly seen.
Would it be possible to change the color of them to a more contrasting one, or just to increase its width a little bit?
Thanks!

[RodneyBaker]

As other improvements have been made to gap management... in particular the ability to set the gap size for fill to higher distances... this issue has lost some traction. As such it will likely slip to the 2020 development cycle.

One thing that those advocating improvement can do is to further document issues specifically tied to the Gap Check Tool as well as identify where in the code the changes need to be affected asand what the ultimate resolution might look like.

[RodneyBaker]

As of this date the gap check line remains very hard to see.
They appear to be zero thickness lines as they disappear entirely when the Show Zero Thickness Lines option is turned off.

[gab3d]

yes.
sadly it really undermines the usefulness of this particular check.

[RodneyBaker]

I'll try to set aside some time to locate the Gap Check code that controls that line.
As you suggest @gab3d, the feature is not useful without being able to see the line.

[ghost]

In many cases, I find that the gap check is not very useful. Even if not perfect I prefer the cacani approach which highlights with a circular spot each end of a line that does not meet another line. It's easier to spot check the cases that can be a problem.

[flurick]

toonz/sources/toonzlib/stagevisitor.cpp:756

[flurick]

Quick test patch to see how it looks flurick@18c2491