[Kst] Crash trace...

[Barth Netterfield]

What are the problems with letting the user shrink to 0 size?

It seems to me that we will be chasing opportunities for user foolishness all 
day, when all we need to do is Andrew's Guard (or am I missing something?)

cbn

On March 16, 2005 03:04 pm, George Staikos wrote:
> On Wednesday 16 March 2005 14:34, Andrew Walker wrote:
> > As before, create a plot in a window, set number of columns to 10, shrink
> > window in horizontal direction, crash...
> >
> > On Wednesday 16 March 2005 11:33 am, George Staikos wrote:
> > > Which of your testcases caused this? (Or was it a different one?)
> > >
> > > On Wednesday 16 March 2005 14:28, Andrew Walker wrote:
> > > > Here's a trace of the crash (caused by the newly introduced assert)
> > > > when the pixmap size goes to zero:
> > > > [KCrash handler]
> > > > #4  0xf6fe97a2 in _dl_sysinfo_int80 () from /lib/ld-linux.so.2
> > > > #5  0xf5b0e955 in raise () from /lib/tls/libc.so.6
> > > > #6  0xf5b10319 in abort () from /lib/tls/libc.so.6
> > > > #7  0xf5b07f41 in __assert_fail () from /lib/tls/libc.so.6
> > > > #8  0x080adde3 in Kst2DPlot::draw (this=0x9c9c260) at qpixmap.h:271
>
>   Ok got it.  The problem is having more plots than there are pixels in a
> given dimension.  This can be a problem for the layout algorithm too, so
> let's prevent it.  (It's a nonsensical case anyway, so there's no issue
> with preventing it, as you already identified with the cap.)  The view
> widget should have a minimum size too.
>
>   Now we also have the issue of resizing and moving plots manually, ie: not
> in columns.  It should be impossible to resize a plot smaller than 1x1
> already. However the regrid code could be abused also.  A user could create
> 1000 plots and then regrid with a minimum size window.  Again, it's absurd
> and that itself should probably be guarded against.
>
>   The problem with a null pixmap is that it implies view objects that can't
> be manipulated.  I think it's completely wrong to have this happen, ever. 
> I think a good start is:
>
> - Set maximum number of columns (done)
> - Set minimum size of kstviewwidget to at least 40x25
> - Set maximum number of 2dplot children of any view object to 200
>
> This still doesn't deal with the nested view object case, but I think it
> mostly covers us.  A kst file or dcop call that tries to create a null view
> object should trigger an error and refuse to load further.