IIRC this add-on is not part of the official blender distribution, so we cannot support it here, so I'm going to close the report.

Not ported yet to 2.8.

@Philipp Oeser (lichtwerk) Since yesterday or the day before, I cannot change the priority of the tasks.

@Campbell Barton (campbellbarton) Could you take a look of this because you know how works Toolbar?

We need a file to test. Could you provide a simple file with this error?

This is not supported yet... added to ToDo list.

@Charlie Jolly (charlie) Commit in 2.8 and then merge to greasepencil-object to keep the branch updated to last version.

@Charlie Jolly (charlie) If you can, please email me or contact by private message in twitter to provide you a link to a chat we have for discuss GP topics with all GP member teams. You can also contact with @Daniel Lara (Pepeland) (pepeland) or @Matias Mendiola (mendio) . Use phabricator for this is not the best solution.

Ok. If the AKEY does not work adding new curve maybe you need review the initialization of the buffer stroke and don't clean it after the operator finish.

@Charlie Jolly (charlie) I have seen several things, but the tool in general looks great:

Closed as duplicated of T57538

In the branch the stroke is drawn while do the primitive (2bcc5f8bdef7)

I just merge 2.8 in GP branch.

@Charlie Jolly (charlie) I have been thinking and IMHO it's mandatory to do all this stuff in greasepencil-object branch. Add new/change operators and add real stroke drawing in primitives can break the current 2.8 version, and now we have users, so we cannot test things there (if something is broken we will receive a lot of bugs and we will need time to manage them).

@Charlie Jolly (charlie) To get the preview while drawing you need fill the stroke buffer with the points. Also, we need to be sure the buffer is cleared at the end of the operator (you can see an example in gpencil_paint.c)

The changes look good in general, only review that you calc the integer conversion only once and try to use only one variable definition. Really, this is not an issue running the code, but makes it more clear.

@Charlie Jolly (charlie) Yes, agree. Real Beziers is totally different, but we can add this primitive now.

I see that you have created a internal function to make the float conversion, so this is ok as solution for primitives. I think in Blender 2.81 we must back here and redo the primitives including a full support for Bezier curves.

There are reasons to have 2 switches:

Firstly, I like the idea of primitives with Bezier curves, but do we want only this? I mean, maybe we need to think in a new whole type of strokes "Curves" and keep all the information to allow editing. Sometimes you could need to refine or reshape the curve. Anyway, I like the primitive that you describe, but maybe we need to be "careful" with the name we give, Bezier curves are too wide and the users will expect more of this type of tool.

About simplify, I need to know what mode you used, fixed? if you used fixed, the stroke points are removed alternated points and keep extremes, so maybe the final result is not perfect, really this algorithm is not done to simplify arcs.

I agree a complete change is better than hack code, but is now the right moment to do that?

@Charlie Jolly (charlie) You can commit, icon will be added later.

Only one concern... not sure if we must wait for the new icon before commit the new feature.

@Charlie Jolly (charlie) About Bezier curves, I think is good idea add this feature but not now.

@Brecht Van Lommel (brecht) Do you have any idea here? I always thought the gizmo used the transformation center.

@Charlie Jolly (charlie) I like the additions you are doing, maybe add arrows would be great... and text will be awesome too.

All the credits of this fix code goes to @Brecht Van Lommel (brecht)

Solved with fadad895b2f4

Thanks @Brecht Van Lommel (brecht) your solution is by far better than mine... I was almost sure my solution was totally wrong.

Duplicated.

@Brecht Van Lommel (brecht) If you have some time, could you help me with this?

Please provide a complete report of your bug, steps to reproduce, simple file, etc.