Re: Viewport diagonal scrolling redraw

[rendaw <rendaw zarbosoft com>]

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On February 16, 2011 at 12:45 PM jcupitt gmail com wrote:

> On 16 February 2011 04:48, Rendaw <rendaw zarbosoft com> wrote:
> > As a side note, does gdk_window_process_updates() preserve mouse motion
> > events when the MOTION_HINT mask is set? ÂI also had motion event queuing
> > problems (I would stop moving the mouse but the screen would continually
> > redraw for a few seconds until it had caught up) before I moved the
> > gtk_adjustment_set_value()'s out of the motion handling code and into a
> > g_idle_add callback.
>
> I don't know how to get silky diagonal scrolling easily, but I can
> help here (I think). The solution I found was to calculate all mouse
> movement relative to the root window, not the window being scrolled.
>
> In the motion event, there are a couple of fields called x_root and
> y_root. Record these on button down together with the scroll position
> of the underlying window, then during motion, scroll the window to the
> position found by subtracting the start x_root from the current x_root
> plus the original x.
>
> This makes these feedback effects (which can be bizarre and horrible)
> impossible.
>
> John
Ah thanks, I might try that, it might be a bit cleaner than what I have now.
ÂThat problem isn't actually feedback, I think -- but repeated expose events not
being dropped (despite the motion hint, because of gdk_window_process_updates).
ÂIt's more like watching a slo-mo video of your previous actions. ÂThe feedback
thing I have licked for now.