[chronojump] Encoder improved smoothing. Great on start/end, and same values for set/repetition

[Xavier de Blas <xaviblas src gnome org>]

commit c867cc795110b3ec6b345ec689b38b90dd7d285d
Author: Xavier de Blas <xaviblas gmail com>
Date:   Tue Jan 12 00:06:36 2016 +0100

    Encoder improved smoothing. Great on start/end, and same values for set/repetition

 encoder/util.R |   21 ++++++++++++++++++++-
 1 files changed, 20 insertions(+), 1 deletions(-)
---
diff --git a/encoder/util.R b/encoder/util.R
index b4a044b..13f032d 100644
--- a/encoder/util.R
+++ b/encoder/util.R
@@ -238,9 +238,28 @@ getSpeedSafe <- function(displacement, smoothing) {
        else
                return(list(y=rep(0,length(displacement))))
 }
+#unused since 1.6.0 because first and last displacement values make change too much the initial and end curve
+#getSpeedOld <- function(displacement, smoothing) {
+#      #no change affected by encoderConfiguration
+#      return (smooth.spline( 1:length(displacement), displacement, spar=smoothing))
+#}
 getSpeed <- function(displacement, smoothing) {
        #no change affected by encoderConfiguration
-       return (smooth.spline( 1:length(displacement), displacement, spar=smoothing))
+       
+       #use position because this does not make erronously change the initial and end of the curve
+       #do spline with displacement is buggy because data is too similar -2, -1, 0, 1, 2, ...
+       position <- cumsum(displacement)
+       positionSpline <- smooth.spline( 1:length(position), position, spar=smoothing)
+       
+       #get speed converting from position to displacement, but repeat first value because it's missing on 
the diff process
+       #do not hijack spline like this because this works for speed, but then acceleration has big error
+       #speedSpline = positionSpline
+       #speedSpline$y = c(diff(positionSpline$y)[1],diff(positionSpline$y))
+
+       speed = c(diff(positionSpline$y)[1],diff(positionSpline$y))
+       speedSpline <- smooth.spline( 1:length(speed), speed, spar=0) #don't do smoothing, just convert speed 
to an spline
+
+       return (speedSpline)
 }
 
 getAccelerationSafe <- function(speed) {