Corrections based on dimension analysis

The biggest change is to the speed and acceleration parameters, which should
now scale properly.  Starting from one end and moving a finger really slowly
across the touchpad, the pointer should move about 40 percent of the way from
one end to the other. Repeating the process more quickly, the pointer should
move about 70 percent. Finally, moving really quickly, the pointer should
reach the the other end of the screen before the whole touchpad has been
crossed.

Settings tested on appletouch, synaptics, and bcm5974.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Peter Hutterer <peter.hutterer@redhat.com>

1 files changed, 21 insertions, 26 deletions

diff --git a/src/synaptics.c b/src/synaptics.c
index 6b2cc43..29c1f46 100644
--- a/src/synaptics.c
+++ b/src/synaptics.c
@@ -304,16 +304,16 @@ static void set_default_parameters(LocalDevicePtr local)
     pointer opts = local->options; /* read-only */
     SynapticsSHM *pars = &priv->synpara_default; /* modified */
 
-    float minSpeed, maxSpeed;
-    int horizScrollDelta, vertScrollDelta,
-        edgeMotionMinSpeed, edgeMotionMaxSpeed;
-    int tapMove;
+    int horizScrollDelta, vertScrollDelta;		/* pixels */
+    int tapMove;					/* pixels */
     int l, r, t, b; /* left, right, top, bottom */
-    int fingerLow, fingerHigh, fingerPress;
-    int emulateTwoFingerMinZ;
-    int edgeMotionMinZ, edgeMotionMaxZ;
-    int pressureMotionMinZ, pressureMotionMaxZ;
-    int palmMinWidth, palmMinZ;
+    int edgeMotionMinSpeed, edgeMotionMaxSpeed;		/* pixels/second */
+    double accelFactor;					/* 1/pixels */
+    int fingerLow, fingerHigh, fingerPress;		/* pressure */
+    int emulateTwoFingerMinZ;				/* pressure */
+    int edgeMotionMinZ, edgeMotionMaxZ;			/* pressure */
+    int pressureMotionMinZ, pressureMotionMaxZ;		/* pressure */
+    int palmMinWidth, palmMinZ;				/* pressure */
     int tapButton1, tapButton2, tapButton3;
     int clickFinger1, clickFinger2, clickFinger3;
     Bool vertEdgeScroll, horizEdgeScroll;
@@ -331,11 +331,12 @@ static void set_default_parameters(LocalDevicePtr local)
      */
     if (priv->minx < priv->maxx && priv->miny < priv->maxy)
     {
-        int width, height;
+        int width, height, diag;
         int ewidth, eheight; /* edge width/height */
 
         width = abs(priv->maxx - priv->minx);
         height = abs(priv->maxy - priv->miny);
+        diag = sqrt(width * width + height * height);
         ewidth = width * .04;
         eheight = height * .055;
 
@@ -344,31 +345,25 @@ static void set_default_parameters(LocalDevicePtr local)
         t = priv->miny + eheight;
         b = priv->maxy - eheight;
 
-        /* Default min/max speed are 0.09/0.18. Assuming we have a device that
-         * reports height 3040 (typical y range in synaptics specs) this gives
-         * us the same result. */
-        minSpeed = 273.0/height;
-        maxSpeed = 547.0/height;
-
         /* Again, based on typical x/y range and defaults */
-        horizScrollDelta = width * .025;
-        vertScrollDelta = height * .04;
+        horizScrollDelta = diag * .020;
+        vertScrollDelta = diag * .020;
+        tapMove = diag * .044;
         edgeMotionMinSpeed = 1;
-        edgeMotionMaxSpeed = width * .1;
-        tapMove = width * .055;
+        edgeMotionMaxSpeed = diag * .080;
+        accelFactor = 50.0 / diag;
     } else {
         l = 1900;
         r = 5400;
         t = 1900;
         b = 4000;
-        minSpeed = 0.09;
-        maxSpeed = 0.18;
 
         horizScrollDelta = 100;
         vertScrollDelta = 100;
+        tapMove = 220;
         edgeMotionMinSpeed = 1;
         edgeMotionMaxSpeed = 400;
-        tapMove = 220;
+        accelFactor = 0.010;
     }
 
     if (priv->minp < priv->maxp) {
@@ -483,9 +478,9 @@ static void set_default_parameters(LocalDevicePtr local)
     pars->press_motion_min_z = xf86SetIntOption(opts, "PressureMotionMinZ", pressureMotionMinZ);
     pars->press_motion_max_z = xf86SetIntOption(opts, "PressureMotionMaxZ", pressureMotionMaxZ);
 
-    pars->min_speed = synSetFloatOption(opts, "MinSpeed", minSpeed);
-    pars->max_speed = synSetFloatOption(opts, "MaxSpeed", maxSpeed);
-    pars->accl = synSetFloatOption(opts, "AccelFactor", 0.050);
+    pars->min_speed = synSetFloatOption(opts, "MinSpeed", 0.4);
+    pars->max_speed = synSetFloatOption(opts, "MaxSpeed", 0.7);
+    pars->accl = synSetFloatOption(opts, "AccelFactor", accelFactor);
     pars->trackstick_speed = synSetFloatOption(opts, "TrackstickSpeed", 40);
     pars->scroll_dist_circ = synSetFloatOption(opts, "CircScrollDelta", 0.1);
     pars->coasting_speed = synSetFloatOption(opts, "CoastingSpeed", 0.0);