[SciPy-User] (no subject)

[Alex Liberzon]

Hi,

While moving from Matlab to Numpy/Scipy/Matplotlib I need sometimes to work with Matlab figures. It would be nice if we could load Matlab figures in Python, extract the data and some basic parameters of how it was looking in Matlab and create its "clone" in matplotlib. At present the Matlab figures are MAT files and in the near future it will be HDF5, both formats are loadable. However, I have not found any reference for such attempts to load and parse the FIG files. As a beginner I find it difficult to write a large piece of code. However, if there are other  interested users that can cooperate on such, I'd gladly contribute some hours for this task. Meanwhile, to show the proof-of-concept attempt is attached below. All your useful comments and suggestions are very welcome. 

Thank you,
Alex 

#------------ loadfig.py ---------------------- #
""" Loadfig loads simple Matlab figures as MAT files and plots the lines using matplotlib

"""
import numpy as np
from scipy.io import loadmat
import matplotlib.pyplot as plt


def lowest_order(d):
	""" 
	lowestsc_order(hgstruct) finds the handle of axes (i.e. children of figure handles, etc.)
	
	"""
	while not 'graph2d.lineseries' in d['type']:
		d = d['children'][0][0]
	return d
	
def get_data(d):
	""" 
	get_data(hgstruct) extracts XData, YData, Color and Marker of each line in the 
	given axis
	
	Parameters
	----------
	hgstruct : structure 
		obtained from lowest_order(loadmat('matlab.fig'))
	
	"""
	xd,yd,dispname,marker,colors = [],[],[],[],[]
	for i in d:
		if i['type'] == 'graph2d.lineseries':
			xd.append(i['properties'][0][0]['XData'][0][0])
			yd.append(i['properties'][0][0]['YData'][0][0])
			dispname.append(i['properties'][0][0]['DisplayName'][0][0])
			marker.append(i['properties'][0][0]['Marker'][0][0])
			colors.append(i['properties'][0][0]['Color'][0][0])
			
	return np.asarray(xd),np.asarray(yd),dispname,np.asarray(marker).astype('S1'),colors


def plot_data(xd,yd,dispname=None,marker=None,colors=None):
	"""
	plot_data(xd,yd,dispname=None,marker=None,colors=None)
	
	plots the data sets extracted by get_data(lowest_order(loadmat('matlab.fig')))	
	
	Parameters
	----------
		xd,yd : array_like
			data arrays 
		dispname : array of strings 
			to be used in legend, optional
		marker : array of characters
			markers, e.g. ['o','x'], optional
		colors : array of color sets 
			in RGB, e.g. [[0,0,1],[1,0,0]], optional
			
		
	"""
	for i,n in enumerate(xd):
		plt.plot(xd[i].T,yd[i].T,color=tuple(colors[i]),marker=marker[i],linewidth=0)
		
	plt.legend(dispname)
	plt.show()

def main(filename):
	"""
	main(filename) 
	
	loads the filename (with the extension .fig) which is Matlab figure. At the moment only
	simple 2D lines are supported. 
	
	Examples
	-------
	>>> loadfig('matlab.fig') # is equivalent to:
	
	>>> d = loadmat(filename)
	>>> d = d['hgS_070000']
	>>> xd,yd,dispname,marker,colors = get_data(lowest_order(d))
	>>> plot_data(xd,yd,dispname,marker,colors)
	
	"""
	d = loadmat(filename)
	# ver 7.2 or lower:
	d = d['hgS_070000']
	xd,yd,dispname,marker,colors = get_data(lowest_order(d))
	plot_data(xd,yd,dispname,marker,colors)


if __name__ == "__main__":
    import sys
    import os
    try:
    	filename = sys.argv[1]
       	main(filename)
    except:
    	print("Wrong file")
# ----------------------------- EOF loadfig.py --------------------------- # 

Alex Liberzon
Turbulence Structure Laboratory [http://www.eng.tau.ac.il/efdl]
School of Mechanical Engineering
Tel Aviv University
Ramat Aviv 69978
Israel
Tel: +972-3-640-8928
Lab: +972-3-640-6860 (telefax)
E-mail: alexlib at eng.tau.ac.il