Re: Strange autoscaling with rgbimage and inverted yranges

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

On Friday, 11 September 2020 22:51:03 PDT Ethan A Merritt wrote:

> I _think_ that the problem involves this macro in axis.h
> 
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> /* Simplest form of autoscaling (no check on autoscale constraints).
>  * Used by refresh_bounds() and refresh_3dbounds().
>  * Used also by autoscale_boxplot.
>  */
> #define autoscale_one_point(axis, x) do {\
>     if (axis->set_autoscale & AUTOSCALE_MIN && x < axis->min) \
>         axis->min = x; \
>     if (axis->set_autoscale & AUTOSCALE_MAX && x > axis->max) \
>         axis->max = x; \
>     } while (0);
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> 
> as called from plot2d.c:refresh_bounds() when zooming volatile data.
> 
> Note that the macro does not consider the case of reversed axes.
> Adding a test for (axis->min < axis->max) seems to make your
> test case work.   See attached patch.

Better patch (but still not fully correct)

	Ethan