dix: support the transformation matrix for relative devices.

The transformation matrix we previously stored was a scaled matrix based on
the axis ranges of the device. For relative movements, the scaling is not
required (or desired).

Store two separate matrices, one as requested by the client, one as the
product of [scale . matrix . inv_scale]. Depending on the type of movement,
apply the respective matrix.

For relative movements, also drop the translation component since it doesn't
really make sense to use that bit.

Input ABI 19

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

3 files changed, 45 insertions, 11 deletions

diff --git a/dix/devices.c b/dix/devices.c
index 172fc0460..530f15d66 100644
--- a/dix/devices.c
+++ b/dix/devices.c
@@ -93,9 +93,10 @@ SOFTWARE.
 static void RecalculateMasterButtons(DeviceIntPtr slave);
 
 static void
-DeviceSetTransform(DeviceIntPtr dev, float *transform)
+DeviceSetTransform(DeviceIntPtr dev, float *transform_data)
 {
     struct pixman_f_transform scale;
+    struct pixman_f_transform transform;
     double sx, sy;
     int x, y;
 
@@ -122,16 +123,21 @@ DeviceSetTransform(DeviceIntPtr dev, float *transform)
     /* transform */
     for (y = 0; y < 3; y++)
         for (x = 0; x < 3; x++)
-            dev->transform.m[y][x] = *transform++;
+            transform.m[y][x] = *transform_data++;
 
-    pixman_f_transform_multiply(&dev->transform, &scale, &dev->transform);
+    pixman_f_transform_multiply(&dev->scale_and_transform, &scale, &transform);
 
     /* scale */
     pixman_f_transform_init_scale(&scale, 1.0 / sx, 1.0 / sy);
     scale.m[0][2] = -dev->valuator->axes[0].min_value / sx;
     scale.m[1][2] = -dev->valuator->axes[1].min_value / sy;
 
-    pixman_f_transform_multiply(&dev->transform, &dev->transform, &scale);
+    pixman_f_transform_multiply(&dev->scale_and_transform, &dev->scale_and_transform, &scale);
+
+    /* remove translation component for relative movements */
+    dev->relative_transform = transform;
+    dev->relative_transform.m[0][2] = 0;
+    dev->relative_transform.m[1][2] = 0;
 }
 
 /**
@@ -308,9 +314,10 @@ AddInputDevice(ClientPtr client, DeviceProc deviceProc, Bool autoStart)
     /* unity matrix */
     memset(transform, 0, sizeof(transform));
     transform[0] = transform[4] = transform[8] = 1.0f;
-    dev->transform.m[0][0] = 1.0;
-    dev->transform.m[1][1] = 1.0;
-    dev->transform.m[2][2] = 1.0;
+    dev->relative_transform.m[0][0] = 1.0;
+    dev->relative_transform.m[1][1] = 1.0;
+    dev->relative_transform.m[2][2] = 1.0;
+    dev->scale_and_transform = dev->relative_transform;
 
     XIChangeDeviceProperty(dev, XIGetKnownProperty(XI_PROP_TRANSFORM),
                            XIGetKnownProperty(XATOM_FLOAT), 32,
diff --git a/dix/getevents.c b/dix/getevents.c
index 7cc8d8cb5..a4f192cf0 100644
--- a/dix/getevents.c
+++ b/dix/getevents.c
@@ -1202,6 +1202,27 @@ transform(struct pixman_f_transform *m, double *x, double *y)
     *y = p.v[1];
 }
 
+static void
+transformRelative(DeviceIntPtr dev, ValuatorMask *mask)
+{
+    double x = 0, y = 0;
+
+    valuator_mask_fetch_double(mask, 0, &x);
+    valuator_mask_fetch_double(mask, 1, &y);
+
+    transform(&dev->relative_transform, &x, &y);
+
+    if (x)
+        valuator_mask_set_double(mask, 0, x);
+    else
+        valuator_mask_unset(mask, 0);
+
+    if (y)
+        valuator_mask_set_double(mask, 1, y);
+    else
+        valuator_mask_unset(mask, 1);
+}
+
 /**
  * Apply the device's transformation matrix to the valuator mask and replace
  * the scaled values in mask. This transformation only applies to valuators
@@ -1229,7 +1250,7 @@ transformAbsolute(DeviceIntPtr dev, ValuatorMask *mask)
         ox = dev->last.valuators[0];
         oy = dev->last.valuators[1];
 
-        pixman_f_transform_invert(&invert, &dev->transform);
+        pixman_f_transform_invert(&invert, &dev->scale_and_transform);
         transform(&invert, &ox, &oy);
 
         x = ox;
@@ -1242,7 +1263,7 @@ transformAbsolute(DeviceIntPtr dev, ValuatorMask *mask)
     if (valuator_mask_isset(mask, 1))
         oy = y = valuator_mask_get_double(mask, 1);
 
-    transform(&dev->transform, &x, &y);
+    transform(&dev->scale_and_transform, &x, &y);
 
     if (valuator_mask_isset(mask, 0) || ox != x)
         valuator_mask_set_double(mask, 0, x);
@@ -1403,6 +1424,8 @@ fill_pointer_events(InternalEvent *events, DeviceIntPtr pDev, int type,
             set_raw_valuators(raw, &mask, raw->valuators.data);
     }
     else {
+        transformRelative(pDev, &mask);
+
         if (flags & POINTER_ACCELERATE)
             accelPointer(pDev, &mask, ms);
         if ((flags & POINTER_NORAW) == 0)
diff --git a/include/inputstr.h b/include/inputstr.h
index 48a29bede..de96faeda 100644
--- a/include/inputstr.h
+++ b/include/inputstr.h
@@ -588,8 +588,12 @@ typedef struct _DeviceIntRec {
         XIPropertyHandlerPtr handlers;  /* NULL-terminated */
     } properties;
 
-    /* coordinate transformation matrix for absolute input devices */
-    struct pixman_f_transform transform;
+    /* coordinate transformation matrix for relative movement. Matrix with
+     * the translation component dropped */
+    struct pixman_f_transform relative_transform;
+    /* scale matrix for absolute devices, this is the combined matrix of
+       [1/scale] . [transform] . [scale]. See DeviceSetTransform */
+    struct pixman_f_transform scale_and_transform;
 
     /* XTest related master device id */
     int xtest_master_id;