/**
* Compute acceleration. Takes into account averaging, nv-reset, etc.
* If the velocity has changed, an average is taken of 6 velocity factors:
* current velocity, last velocity and 4 times the average between the two.
*/
static double
ComputeAcceleration(DeviceIntPtr dev,
DeviceVelocityPtr vel, double threshold, double acc)
{
double result;
if (vel->velocity <= 0) {
DebugAccelF("profile skipped\n");
/*
* If we have no idea about device velocity, don't pretend it.
*/
return 1;
}
if (vel->average_accel && vel->velocity != vel->last_velocity) {
/* use simpson's rule to average acceleration between
* current and previous velocity.
* Though being the more natural choice, it causes a minor delay
* in comparison, so it can be disabled. */
result =
BasicComputeAcceleration(dev, vel, vel->velocity, threshold, acc);
result +=
BasicComputeAcceleration(dev, vel, vel->last_velocity, threshold,
acc);
result +=
4.0f * BasicComputeAcceleration(dev, vel,
(vel->last_velocity +
vel->velocity) / 2,
threshold,
acc);
result /= 6.0f;
DebugAccelF("profile average [%.2f ... %.2f] is %.3f\n",
vel->velocity, vel->last_velocity, result);
}
else {
result = BasicComputeAcceleration(dev, vel,
vel->velocity, threshold, acc);
DebugAccelF("profile sample [%.2f] is %.3f\n",
vel->velocity, result);
}
return result;
}
/**
* Compute acceleration. Takes into account averaging, nv-reset, etc.
*/
static float
ComputeAcceleration(
DeviceVelocityPtr vel,
float threshold,
float acc){
float res;
if(vel->last_reset){
DebugAccelF("(dix ptracc) profile skipped\n");
/*
* This is intended to override the first estimate of a stroke,
* which is too low (see ProcessVelocityData). 1 should make sure
* the mickey is seen on screen.
*/
return 1;
}
if(vel->average_accel && vel->velocity != vel->last_velocity){
/* use simpson's rule to average acceleration between
* current and previous velocity.
* Though being the more natural choice, it causes a minor delay
* in comparison, so it can be disabled. */
res = BasicComputeAcceleration(vel, vel->velocity, threshold, acc);
res += BasicComputeAcceleration(vel, vel->last_velocity, threshold, acc);
res += 4.0f * BasicComputeAcceleration(vel,
(vel->last_velocity + vel->velocity) / 2,
threshold, acc);
res /= 6.0f;
DebugAccelF("(dix ptracc) profile average [%.2f ... %.2f] is %.3f\n",
vel->velocity, vel->last_velocity, res);
return res;
}else{
res = BasicComputeAcceleration(vel, vel->velocity, threshold, acc);
DebugAccelF("(dix ptracc) profile sample [%.2f] is %.3f\n",
vel->velocity, res);
return res;
}
}
