Re: Strange autoscaling with rgbimage and inverted yranges

[Ethan A M. <me...@uw...>]

On Saturday, 12 September 2020 21:07:58 PDT Dima Kogan wrote:
> Dima Kogan <gn...@di...> writes:
> 
> > Ethan A Merritt <me...@uw...> writes:
> >
> >> And even after tracking it that far I still don't understand why
> >> 'p' works and 'u' doesn't.     If you can figure that out I'd be 
> >> happier with declaring it fixed.
> >
> > In my tests just now 'p' and 'u' both show this issue. Are you 100% sure
> > that 'p' does NOT show the issue for you?
> 
> I just tried this with the x11, qt and wxt terminals, and in all 3 cases
> both 'u' and 'p' show this issue. I'm at the git HEAD as off a few days
> ago:
> 
>   commit 160d7511bcbdfd0d1943a624af5fc42504a9f84c
>   Author: Ethan A Merritt <merritt@u.washington.edu>
>   Date:   Thu Sep 3 20:20:23 2020 -0700
> 
>       new function (long)argb = rgbcolor("name")
> 
> The test is:
> 
> 1. start gnuplot
> 2. "load" the script in the first email in this thread
> 3. interactively zoom
> 4. 'u' or 'p'
> 
> I'm on GNU/Linux. If I can reproduce the behavior you're seeing ('p' and
> 'u' work differently), then I'll be happy to debug it.

Try this:

1) start gnuplot
2) load script
3) zoom
4) 'u'
   plot is now incorrectly scaled
5) 'n'
   shows zoom state from (3)
6) 'p'
   correctly unzooms to original plot

Now that I try more sequences I notice that replacing 'p' with 'u'
in step (6) also works correctly.  So maybe the issue is whether
the previous operation was 'n'?  Or there's some parity issue
with the count of operations? 

Regardless, I think autoscaling in the current HEAD now works
correctly for your test case.
I also think that it is incorrect for the unzoom operation to invoke
autoscaling at all, but that would require additional code changes.

	Ethan