LessTif HID: XmScrollBar Warnings

[Chad Parker]

In the LessTif HID, when zoomed out such that at least one dimension of the board is smaller than the dimension of the drawing area, LessTif emits warnings in the console:

Warning:
    Name: hscroll
    Class: XmScrollBar
    The specified scrollbar value is less than the minimum
    scrollbar value.

Warning:
    Name: vscroll
    Class: XmScrollBar
    The specified scrollbar value is less than the minimum
    scrollbar value.

[Bert Timmerman (bert-timmerman)]

Hi Chad,

I grep'ed for "set_scroll" in src/hid/lesstif/main.c and found this near line 1219:

void
lesstif_pan_fixup ()
{
#if 0
  if (view_left_x > PCB->MaxWidth - (view_width * view_zoom))
    view_left_x = PCB->MaxWidth - (view_width * view_zoom);
  if (view_top_y > PCB->MaxHeight - (view_height * view_zoom))
    view_top_y = PCB->MaxHeight - (view_height * view_zoom);
  if (view_left_x < 0)
    view_left_x = 0;
  if (view_top_y < 0)
    view_top_y = 0;
  if (view_width * view_zoom > PCB->MaxWidth
      && view_height * view_zoom > PCB->MaxHeight)
    {
      zoom_by (1, 0, 0);
      return;
    }
#endif

  set_scroll (hscroll, view_left_x, view_width, PCB->MaxWidth);
  set_scroll (vscroll, view_top_y, view_height, PCB->MaxHeight);

  lesstif_invalidate_all ();
}

Could you please test if removing the "#if 0" and "#endif" compiler directives solves the issue ?

Kind regards,

Bert Timmerman.

[Bert Timmerman (bert-timmerman)]

ping ;-)

[Chad Parker (parker-charles)]

As it is, it causes a segfault. Looking at the backtrace shows what appears
to be an infinite loop between lesstif_pan_fixup and zoom_to (I stopped
looking after 25000 calls in the backtrace).

I added a one line check in set_scroll that checks the bounds and updates
the set point. Pushed to LP1670023.

On Sun, Aug 27, 2017 at 9:32 AM, Bert Timmerman <email address hidden>
wrote:

> ping ;-)
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1670023
>
> Title:
> LessTif HID: XmScrollBar Warnings
>
> Status in pcb:
> Triaged
>
> Bug description:
> In the LessTif HID, when zoomed out such that at least one dimension
> of the board is smaller than the dimension of the drawing area,
> LessTif emits warnings in the console:
>
> Warning:
> Name: hscroll
> Class: XmScrollBar
> The specified scrollbar value is less than the minimum
> scrollbar value.
>
> Warning:
> Name: vscroll
> Class: XmScrollBar
> The specified scrollbar value is less than the minimum
> scrollbar value.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/pcb/+bug/1670023/+subscriptions
>

[Bert Timmerman (bert-timmerman)]

Pushed to master.

Thanks and kind regards,

Bert Timmerman.