[RFC XI 2.1 - xserver 2/9] Fix transformAbsolute

[Chase Douglas]

From: Chase Douglas <chase.douglas at ubuntu.com>

transformAbsolute must use old values if valuator mask doesn't have new
ones, and it must only set new values if there was a change.

Signed-off-by: Chase Douglas <chase.douglas at canonical.com>
---
 dix/getevents.c |   12 ++++++++----
 1 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/dix/getevents.c b/dix/getevents.c
index d2f1025..8ebd63b 100644
--- a/dix/getevents.c
+++ b/dix/getevents.c
@@ -1065,14 +1065,18 @@ transformAbsolute(DeviceIntPtr dev, ValuatorMask *mask)
     struct pixman_f_vector p;
 
     /* p' = M * p in homogeneous coordinates */
-    p.v[0] = valuator_mask_get(mask, 0);
-    p.v[1] = valuator_mask_get(mask, 1);
+    p.v[0] = (valuator_mask_isset(mask, 0) ? valuator_mask_get(mask, 0) :
+              dev->last.valuators[0]);
+    p.v[1] = (valuator_mask_isset(mask, 1) ? valuator_mask_get(mask, 1) :
+              dev->last.valuators[1]);
     p.v[2] = 1.0;
 
     pixman_f_transform_point(&dev->transform, &p);
 
-    valuator_mask_set(mask, 0, lround(p.v[0]));
-    valuator_mask_set(mask, 1, lround(p.v[1]));
+    if (lround(p.v[0]) != dev->last.valuators[0])
+        valuator_mask_set(mask, 0, lround(p.v[0]));
+    if (lround(p.v[1]) != dev->last.valuators[1])
+        valuator_mask_set(mask, 1, lround(p.v[1]));
 }
 
 /**
-- 
1.7.1