From 3a922c5d07509703a3eeda2bbec6f332e6b0ffac Mon Sep 17 00:00:00 2001
From: Peter Hutterer <peter@cs.unisa.edu.au>
Date: Mon, 28 Apr 2008 17:32:54 +0930
Subject: [PATCH] Xi: apply ValuatorEvent data to the device's valuators.

After UpdateDeviceState, the device has the current position in absolute
coordinates, the event has the correct valuator data to be delivered to the
client.
---
 Xi/exevents.c      | 102 +++++++++++++++++++++++++++++++++++++--------
 include/inputstr.h |   2 +-
 2 files changed, 86 insertions(+), 18 deletions(-)

diff --git a/Xi/exevents.c b/Xi/exevents.c
index a83d5edb3..bbe70e486 100644
--- a/Xi/exevents.c
+++ b/Xi/exevents.c
@@ -823,6 +823,7 @@ UpdateDeviceState(DeviceIntPtr device, xEvent* xE, int count)
 	if ((++xV)->type == DeviceValuator) {
 	    int *axisvals;
             int first = xV->first_valuator;
+            BOOL change = FALSE;
 
 	    if (xV->num_valuators &&
                 (!v || (xV->num_valuators &&
@@ -830,24 +831,91 @@ UpdateDeviceState(DeviceIntPtr device, xEvent* xE, int count)
 		FatalError("Bad valuators reported for device %s\n",
 			   device->name);
 	    if (v && v->axisVal) {
+                /* The device always stores values in absolute. Only the
+                 * delivery mode changes.
+                 * If device is mode Absolute, and event is Relative
+                 *     dev += event
+                 *     event = dev
+                 * If device is mode Absolute, and event is Absolute
+                 *     dev = event
+                 * If device is mode Relative, and event is Absolute
+                 *      swap = (event - device)
+                 *      dev = event
+                 *      event = delta
+                 * If device is mode Relative, and event is Relative
+                 *      dev += event
+                 *
+                 * XXX: axis clipping for relative events?
+                 */
 		axisvals = v->axisVal;
-		switch (xV->num_valuators) {
-		case 6:
-		    *(axisvals + first + 5) = xV->valuator5;
-		case 5:
-		    *(axisvals + first + 4) = xV->valuator4;
-		case 4:
-		    *(axisvals + first + 3) = xV->valuator3;
-		case 3:
-		    *(axisvals + first + 2) = xV->valuator2;
-		case 2:
-		    *(axisvals + first + 1) = xV->valuator1;
-		case 1:
-		    *(axisvals + first) = xV->valuator0;
-		case 0:
-		default:
-		    break;
-		}
+                if (xV->sequenceNumber & Absolute) {
+                    int delta;
+                    if (v->mode == Relative) /* device reports relative */
+                    {
+                        change = TRUE;
+                        xV->sequenceNumber &= ~Absolute;
+                    }
+
+                    switch (xV->num_valuators) {
+                        case 6:
+                            if (change) delta = xV->valuator5 - *(axisvals + first + 5);
+                            *(axisvals + first + 5) = xV->valuator5;
+                            if (change) xV->valuator5 = delta;
+                        case 5:
+                            if (change) delta = xV->valuator4 - *(axisvals + first + 4);
+                            *(axisvals + first + 4) = xV->valuator4;
+                            if (change) xV->valuator4 = delta;
+                        case 4:
+                            if (change) delta = xV->valuator3 - *(axisvals + first + 3);
+                            *(axisvals + first + 3) = xV->valuator3;
+                            if (change) xV->valuator3 = delta;
+                        case 3:
+                            if (change) delta = xV->valuator2 - *(axisvals + first + 2);
+                            *(axisvals + first + 2) = xV->valuator2;
+                            if (change) xV->valuator2 = delta;
+                        case 2:
+                            if (change) delta = xV->valuator1 - *(axisvals + first + 1);
+                            *(axisvals + first + 1) = xV->valuator1;
+                            if (change) xV->valuator1 = delta;
+                        case 1:
+                            if (change) delta = xV->valuator0 - *(axisvals + first);
+                            *(axisvals + first) = xV->valuator0;
+                            if (change) xV->valuator0 = delta;
+                        case 0:
+                        default:
+                            break;
+                    }
+		} else { /* event is relative */
+                    if (v->mode == Absolute) /* device reports absolute */
+                    {
+                        change = TRUE;
+                        xV->sequenceNumber |= Absolute;
+                    }
+
+                    switch (xV->num_valuators) {
+                        case 6:
+                            *(axisvals + first + 5) += xV->valuator5;
+                            if (change) xV->valuator5 = *(axisvals + first + 5);
+                        case 5:
+                            *(axisvals + first + 4) += xV->valuator4;
+                            if (change) xV->valuator4 = *(axisvals + first + 4);
+                        case 4:
+                            *(axisvals + first + 3) += xV->valuator3;
+                            if (change) xV->valuator3 = *(axisvals + first + 3);
+                        case 3:
+                            *(axisvals + first + 2) += xV->valuator2;
+                            if (change) xV->valuator2 = *(axisvals + first + 2);
+                        case 2:
+                            *(axisvals + first + 1) += xV->valuator1;
+                            if (change) xV->valuator1 = *(axisvals + first + 1);
+                        case 1:
+                            *(axisvals + first) += xV->valuator0;
+                            if (change) xV->valuator0 = *(axisvals + first);
+                        case 0:
+                        default:
+                            break;
+                    }
+                }
 	    }
 	}
     }
diff --git a/include/inputstr.h b/include/inputstr.h
index 8c1d5fc5a..d117e554d 100644
--- a/include/inputstr.h
+++ b/include/inputstr.h
@@ -174,7 +174,7 @@ typedef struct _ValuatorClassRec {
 
     AxisInfoPtr 	  axes;
     unsigned short	  numAxes;
-    int			  *axisVal;
+    int			  *axisVal; /* always absolute, but device-coord system */
     int                   dxremaind, dyremaind; /* for acceleration */
     CARD8	 	  mode;
 } ValuatorClassRec, *ValuatorClassPtr;