[Kde-games-devel] kpat issues (in recent svn)

[Ian Wadham]

On Sat, 23 May 2009 9:14:46 am Parker Coates wrote:
> On Fri, May 22, 2009 at 6:15 PM, Ian Wadham wrote:
> > On Sat, 23 May 2009 12:19:48 am Parker Coates wrote:
> > So what exactly would you like me to test (before I update libraries)?
>
> I find it easiest to reproduce when playing Golf. Maxmise the window
> and just hit Space a bunch of times. It won't happen everytime, so you
> might have to deal out the entire deck and restart a few times before
> you get it. Dealing cards in rapid succession also seems to help. Deal
> a new card before the last one has stopped.
>
Rock-solid here!  I've tried clicking the mouse quickly, pressing the
spacebar rapidly, using the spacebar with 25/sec and 50/sec auto
repeat ... with Golf, Klondike (1-card flip) and Klondike (3-card flip).
Always the top card of the stock pile stays steady.  Theory below.

> >> I've also been able to determine that it is much more likely to happen
> >> at bigger window sizes. I've also changed my local copy of KPat to use
> >> a QGLWidget in the QGraphicsView, and that stops the issue.
> >
> > I tend to play with KPat maximized on a 1280x800 laptop display.
> > Is that big enough?
>
> That's plenty big enough.
>
Larger window-size would make for larger card-size and hence more
re-painting when you flip a card maybe.

I noticed that there is a very fast animation as a card flips over, so fast
as to be hardly perceptible to the naked eye.  I checked the KDE 3.5
version of KPat and that animation seems much slower --- quick, but quite
perceptible.  I also noticed that the card that flips over appears briefly in 
front of the deck beneath and so would clip it.

So my theory is that the animation is too fast for QGraphicsView 4.5, it
gets its knickers in a knot when trying to optimize and forgets to "un-clip"
the stock pile.  Its job would not be any easier if, as I believe someone
mentioned, all the pixmaps of the cards in the stock pile are lying
there on top of each other.

Maybe you could try (in the source code) bypassing the animation,
slowing it down or reducing the graphics for the stock pile to one
card-back pixmap and see what effect that has.  Maybe just
remove the animation ...  If the eye cannot follow it, why have it?

> Thanks a lot for volunteering Ian. I owe you one.
>
No worries.  The Euro is strong right now ... :-)

All the best, Ian W.