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dix: Untwist transformAbsolute logic, eliminate uninitialized value warnings 

tranformAbsolute has a pretty simple job, that of running the X/Y
values from a device through the transformation matrix. The tricky bit
comes when the current device state doesn't include one of the
values. In that case, the last delivered value is back-converted to
device space and used instead.

The logic was twisted though, confusing GCC's uninitialized value
detection logic and emitting warnings.

This has been fixed by changing the code to:

 1) Detect whether the ValuatorMask includes X/Y values
 2) If either are missing, back-convert the current values into ox/oy
 3) When X/Y are present, set ox/oy to the current value
 4) Transform
 5) Store X/Y values if changed or if they were set before.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
This commit is contained in:
Keith Packard 2014-10-22 14:48:10 -07:00
parent 0fbbdb37c8
commit 65dd1ba7b3
1 changed files with 11 additions and 11 deletions
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22
dix/getevents.c
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@ -1248,8 +1248,8 @@ transformAbsolute(DeviceIntPtr dev, ValuatorMask *mask)
double x, y, ox, oy;
int has_x, has_y;
has_x = valuator_mask_fetch_double(mask, 0, &ox);
has_y = valuator_mask_fetch_double(mask, 1, &oy);
has_x = valuator_mask_isset(mask, 0);
has_y = valuator_mask_isset(mask, 1);
if (!has_x && !has_y)
return;
@ -1263,23 +1263,23 @@ transformAbsolute(DeviceIntPtr dev, ValuatorMask *mask)
pixman_f_transform_invert(&invert, &dev->scale_and_transform);
transform(&invert, &ox, &oy);
x = ox;
y = oy;
}
if (valuator_mask_isset(mask, 0))
ox = x = valuator_mask_get_double(mask, 0);
if (has_x)
ox = valuator_mask_get_double(mask, 0);
if (valuator_mask_isset(mask, 1))
oy = y = valuator_mask_get_double(mask, 1);
if (has_y)
oy = valuator_mask_get_double(mask, 1);
x = ox;
y = oy;
transform(&dev->scale_and_transform, &x, &y);
if (valuator_mask_isset(mask, 0) || ox != x)
if (has_x || ox != x)
valuator_mask_set_double(mask, 0, x);
if (valuator_mask_isset(mask, 1) || oy != y)
if (has_y || oy != y)
valuator_mask_set_double(mask, 1, y);
}