[PATCH] dix: undo transformation for missing valuators (#49347)
Chase Douglas
chase.douglas at canonical.com
Mon May 14 17:25:41 PDT 2012
On 05/14/2012 05:21 PM, Chase Douglas wrote:
> On 05/14/2012 04:52 PM, Peter Hutterer wrote:
>> last.valuators contains the transformed valuators of the device. If the
>> device submits events with x/y missing, we need to get that from
>> last.valuators and undo the transformation to that axis.
>>
>> X.Org Bug 49347 <http://bugs.freedesktop.org/show_bug.cgi?id=49347>
>>
>> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
>> ---
>> dix/getevents.c | 18 ++++++++++++++----
>> 1 file changed, 14 insertions(+), 4 deletions(-)
>>
>> diff --git a/dix/getevents.c b/dix/getevents.c
>> index c960d44..d466ebb 100644
>> --- a/dix/getevents.c
>> +++ b/dix/getevents.c
>> @@ -1167,15 +1167,25 @@ transformAbsolute(DeviceIntPtr dev, ValuatorMask *mask)
>> {
>> double x, y, ox, oy;
>>
>> + if (!valuator_mask_isset(mask, 0) || !valuator_mask_isset(mask, 1)) {
>> + struct pixman_f_transform invert;
>> +
>> + /* undo transformation from last event */
>> + ox = dev->last.valuators[0];
>> + oy = dev->last.valuators[1];
>> +
>> + pixman_f_transform_invert(&invert, &dev->transform);
>> + transform(&invert, &ox, &oy);
>> +
>> + x = ox;
>> + y = oy;
>> + }
>> +
>> if (valuator_mask_isset(mask, 0))
>> ox = x = valuator_mask_get_double(mask, 0);
>> - else
>> - ox = x = dev->last.valuators[0];
>>
>> if (valuator_mask_isset(mask, 1))
>> oy = y = valuator_mask_get_double(mask, 1);
>> - else
>> - oy = y = dev->last.valuators[1];
>>
>> transform(&dev->transform, &x, &y);
>>
>
> This all looks like a no-op if neither X nor Y are set in the passed-in
> mask. Why not just return early? I suppose ox != x and/or oy != y after
> the transformation, so we'll always be setting the values in the mask,
> but is that necessary since they haven't changed?
I realized my mistake in the review is when only one of the X and Y axis
values is set. Why don't we combine both by adding the following to the
top of the function:
if (!valuator_mask_isset(mask, 0) && !valuator_mask_isset(mask, 1))
return;
It simply makes an optimized path when neither the X nor Y valuators are
set.
-- Chase
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