Re: [Tuxpaint-devel] Polygon fill messing with other tools drawing

[Pere P. i C. <per...@gm...>]

El dl. 08 de 04 de 2024 a les 21:06 -0700, en/na Bill Kendrick va escriure:
> On Sun, Apr 07, 2024 at 03:11:09PM +0200, Pere Pujal i Carabantes wrote:
> > Hi all,
> > 
> > Tested the new polyfill stuff, it is nice :)
> > 
> > Just found a minor problem:
> 
> "Minor" X-D

Well, polyfill is WIP, I don't consider bugs critical if we are not near a release :)

> 
> 
> > Start Tux Paint, select the Polygon Fill tool.
> > select another tool and draw something.
> > Return to the Polygon Fill tool, see how everything you had drawn is lost.
> > 
> > The problem is polyfill_snapshot being kept and later blit into the canvas via
> > set_color() -> draw_preview() before switchin()
> > 
> > We could clean up polyfill_snapshot at switchout() and recreate it at each swcithin() or
> > we could set some marker, mark it at switchout, clean it up at switchin() and only blit polyfill_snapshot
> > if the marker allows it, that would allow to reuse polyfill_snapshot and not destroy/recreate it
> > at each switchout()/switchin() cycle.
> 
> For now, I've set a variable to tell whether switchin() has been
> called yet.  To me, it seems strange that I'm calling a Magic tool's
> set_color() BEFORE its switchin() has been called.  But rather than
> change that (and potentially break lots of other tools), I've opened a
> ticket. :-)
> 
>   https://sourceforge.net/p/tuxpaint/bugs/286/
> 
> I also addressed an issue I already knew about, where the in-progress
> polygon preview (the lines and big red & green boxes) would remain on
> the canvas when switching to a different tool.


Oh, I thouth it was on purpose, to let children with something painted 
on the screen, in fact the Undo tool still recovers them.


> 
> I believe I solved that by simply blitting the tool's own snapshot
> back to the canvas on switchout().  (And since it makes a fresh
> snapshot after every polygon has been completed, this works.)
> 
> Adjustments like this may help some of the other Magic tools that
> "act weird" when you're in the middle of using them, but then
> switch away.
> 
> I've also thought it might be nice to provide a way for Magic
> tools to say "I can handle the 'Undo' command myself", e.g.
> for Filled Polygon tool, it would remove the most-recently
> added point.  Then, if there's no more work for them to do,
> they can tell Tux Paint that it should do it's normal Undo
> process.
> 
> Prior to that, I also thought it might be interesting to provide a
> way for Magic tools to provide an 'overlay' SDL_Surface which
> Tux Paint would draw on top everything else, rather than having
> to abuse the main `canvas` surface to draw previews, crosshairs,
> grids, etc.
> 
> Things are getting tricky. :)
> 
> -bill!


Currently magic tools that need multiple clicks to do their work 
are tricky, especially when faced to the Undo tool.

Pere


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