[PATCH evdev] Fix absolute events with swapped axes

[Peter Hutterer]

On Wed, Dec 14, 2011 at 03:23:36PM -0200, przanoni at gmail.com wrote:
> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
> 
> We were correctly swapping the valuator values, but we were not
> calling valuator_mask_unset() when needed, so the cursor kept jumping
> to the edges.
> 
> This patch does the swapping before the main "for", so we don't need to
> store unswapped_{x,y} and unswapped_isset_{x,y} even when we don't need
> to swap.
> 
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>

applied, thanks.

Cheers,
  Peter

> ---
>  src/evdev.c |   31 ++++++++++++++++++++++---------
>  1 files changed, 22 insertions(+), 9 deletions(-)
> 
> Another solution to the problem would involve keeping the unswapped_x
> and unswapped_y variables, and also adding unswapped_isset_{x,y}, but I
> believe this one looks better because it just computes these values if
> swap_axes is actually set.
> 
> How I tested:
>  - disabled synaptics
>  - configured my touchpad to report absolute events with evdev
>    - Option "Mode" "Absolute"
>  - xinput --set-prop "SynPS/2 Synaptics TouchPad" "Evdev Axes Swap" 1
> 
> If you move your finger across the touchpad when the axes are inverted
> the cursor keeps jumping to the edges (because we set the valuators to 0
> when what we really wanted was to call valuator_mask_unset). After the
> patch, the cursor acts as we expect. Also, the edges of the touchpad
> match the edges of the screen (the values are scaled correctly).
> 
> diff --git a/src/evdev.c b/src/evdev.c
> index 428d3c1..b1f9b2e 100644
> --- a/src/evdev.c
> +++ b/src/evdev.c
> @@ -436,10 +436,30 @@ EvdevProcessValuators(InputInfoPtr pInfo)
>       * just works.
>       */
>      else if (pEvdev->abs_queued && pEvdev->in_proximity) {
> -        int unswapped_x = valuator_mask_get(pEvdev->vals, 0);
> -        int unswapped_y = valuator_mask_get(pEvdev->vals, 1);
>          int i;
>  
> +        if (pEvdev->swap_axes) {
> +            int swapped_isset[2] = {0, 0};
> +            int swapped_values[2];
> +
> +            for(i = 0; i <= 1; i++)
> +                if (valuator_mask_isset(pEvdev->vals, i)) {
> +                    swapped_isset[1 - i] = 1;
> +                    swapped_values[1 - i] =
> +                        xf86ScaleAxis(valuator_mask_get(pEvdev->vals, i),
> +                                      pEvdev->absinfo[1 - i].maximum,
> +                                      pEvdev->absinfo[1 - i].minimum,
> +                                      pEvdev->absinfo[i].maximum,
> +                                      pEvdev->absinfo[i].minimum);
> +                }
> +
> +            for (i = 0; i <= 1; i++)
> +                if (swapped_isset[i])
> +                    valuator_mask_set(pEvdev->vals, i, swapped_values[i]);
> +                else
> +                    valuator_mask_unset(pEvdev->vals, i);
> +        }
> +
>          for (i = 0; i <= 1; i++) {
>              int val;
>              int calib_min;
> @@ -458,13 +478,6 @@ EvdevProcessValuators(InputInfoPtr pInfo)
>                  calib_max = pEvdev->calibration.max_y;
>              }
>  
> -            if (pEvdev->swap_axes)
> -                val = xf86ScaleAxis((i == 0 ? unswapped_y : unswapped_x),
> -                                    pEvdev->absinfo[i].maximum,
> -                                    pEvdev->absinfo[i].minimum,
> -                                    pEvdev->absinfo[1 - i].maximum,
> -                                    pEvdev->absinfo[1 - i].minimum);
> -
>              if (pEvdev->flags & EVDEV_CALIBRATED)
>                  val = xf86ScaleAxis(val, pEvdev->absinfo[i].maximum,
>                                      pEvdev->absinfo[i].minimum, calib_max,
> -- 
> 1.7.7.3
>