Add a sample GUI script to time-normalize motion and storage files

[mrrezaie]

Hi, many non-scripting OpenSim users may need to time-normalize the output motion/storage files and I think it would be great to provide a GUI script in Resources.zip\Code\GUI, something like this:

import org.opensim.utils as utils
import os

FC = -1 # cutoff frequency for lowpass Butterworth filter (negative means no filter)
N = 101 # number of frames for time normalization (Default = 101 (0-100%))

# choose a file in GUI
fullFileName = utils.FileUtils.getInstance().browseForFilename( \
                utils.FileUtils.MotionFileFilter, 'Select a Motion or Storage File')

# separate directory, file name and the extension 
folderName = os.path.dirname(fullFileName)
fileName, fileExt = os.path.splitext( os.path.basename(fullFileName) )
outputName = os.path.join(folderName, fileName+'_resampled'+fileExt)

# read file
data = modeling.Storage(fullFileName)

# get first and last time frames
tf = data.getFirstTime()
tl = data.getLastTime()

if FC>0:
    # add pad to the signal and apply Butterworth filter
    row = data.size
    data.pad( int(row/2) )
    data.lowpassIIR(FC)
    # data.lowpassFIR(4, FC)
    data.crop(tf,tl) # remove pad

# time interval
dt = float(tl-tf)/(N-1) 

# resample (normalize) to N points
# data.resample(dt, 5)
data.resampleLinear(dt)

data.print(outputName)

print(outputName)
print('Resampled Successfully.')

Thank you.