#!/usr/bin/python # -*- coding: utf-8 -*- # # Initial copyright and message : # Josh Lifton 2004 # # Permission is hereby granted to use and abuse this document # so long as proper attribution is given. # # This Python script demonstrates how to use the numarray package # to generate and handle large arrays of data and how to use the # matplotlib package to generate plots from the data and then save # those plots as images. These images are then stitched together # by Mencoder to create a movie of the plotted data. This script # is for demonstration purposes only and is not intended to be # for general use. In particular, you will likely need to modify # the script to suit your own needs. # # # Heavily modified by C. Joubert to trace rotating field epilog = \ """ Examples GIF output. The only powered coil is coil 1 anim3 -g -1 GIF output. All coils are powered. The resulting field is also plotted. anim3 -g --all -c -r """ # Background image filename bkg_filename='background.png' import argparse parser = argparse.ArgumentParser(description='Create animation of rotating field', epilog=epilog, formatter_class=argparse.RawDescriptionHelpFormatter) parser.add_argument('-1', '--coil1', action='store_true', help='plot coil 1 field') parser.add_argument('-2', '--coil2', action='store_true', help='plot coil 2 field') parser.add_argument('-3', '--coil3', action='store_true', help='plot coil 3 field') parser.add_argument('-A', '--all', action='store_true', help='plot all 3 fields') parser.add_argument('-c', '--compose', action='store_true', help='vectors are plotted "chained"') parser.add_argument('-r', '--resulting', action='store_true', help='draw resulting magnetic field in black') parser.add_argument('-m', '--compass-angle', type=int, default= None, help='draw a compass with given angle shift. Default : no compass drawn') parser.add_argument('-p', '--preserve', action='store_true', help='do not delete individual PartialOut*.png files') parser.add_argument('--fps', type=int, default= 10, help='frames per second') parser.add_argument('-f', '--frames', type=int, default= 40, help='total number or frames') parser.add_argument('-o', '--output', default = 'output_file', help='output file (without extension)') parser.add_argument('-a', '--avi', action='store_true', help='outputs .avi file') parser.add_argument('-g', '--gif', action='store_true', help='outputs .gif file') args = parser.parse_args() # Output filename (without extension) out_filename = args.output # We can get either a .avi movie or an animated GIF (or both) # if neither is set to True, the GUI is launched and the figure plotted into AVI_output = args.avi GIF_output = args.gif numberOfTimeSteps = args.frames # Number of frames we want in the movie. fps = args.fps # Frames per second d=0.05 # margin between figures w1=0.25 # width of sinus. figures h1=0.95*(1-4*d)/3 # height of sinus. figures centerfig=(228,249) # Coordinates of the center of the figure VL=60 # Vector length VHL=10 # Vector arrow dimensions # Which of the current in the three coils is non zero and must be plotted along with the corresponding field ? drawv = [args.coil1 , args.coil2 , args.coil3] if args.all: drawv = [True, True, True] # If set to true, vectors are plotted "chained" compose = args.compose # If set to True, also plots the resulting field drawres = args.resulting # angle de la boussole (en °) par rapport au cham. Si Non : on ne trace pas la boussole if args.compass_angle is None: angle_boussole = None else: angle_boussole = -args.compass_angle # Dessine-t-on les fleches ? draw_arrows = True import matplotlib if AVI_output or GIF_output: matplotlib.use('Agg') import matplotlib.pyplot as plt # For plotting graphs. import matplotlib.image as mpimg import matplotlib.figure as mpfig import matplotlib.patches as mpatches import numpy as np import math import subprocess # For issuing commands to the OS. import os import sys # For determining the Python version. # # Print the version information for the machine, OS, # Python interpreter, and matplotlib. The version of # Mencoder is printed when it is called. # print 'Executing on', os.uname() print 'Python version', sys.version print 'matplotlib version', matplotlib.__version__ not_found_msg = """ The mencoder command was not found; mencoder is used by this script to make an avi file from a set of pngs. It is typically not installed by default on linux distros because of legal restrictions, but it is widely available. """ try: subprocess.check_call(['mencoder']) except subprocess.CalledProcessError: print "mencoder command was found" pass # mencoder is found, but returns non-zero exit as expected # This is a quick and dirty check; it leaves some spurious output # for the user to puzzle over. except OSError: print not_found_msg sys.exit("quitting\n") def draw_triangle(ax, angle, color="red", size=20): points = [ (0, -size), (2*size, 0), (0, +size) ] p_tr = [] angle = -angle # pour s'adapter aux axes for p in points: x = p[0]*math.cos(angle) - p[1]*math.sin(angle) + centerfig[0] y = p[0]*math.sin(angle) + p[1]*math.cos(angle) + centerfig[1] p_tr.append( (x, y) ) p = matplotlib.patches.Polygon(p_tr, closed=True, fill=True, color="k", fc=color) ax.add_patch(p) alph = np.arange(0,2*np.pi,0.05) # Values to be plotted on the x-axis. fig=plt.figure() fig.set_facecolor('w') img=mpimg.imread(bkg_filename) # on dessine l'image du fond (bobines) for i in range(numberOfTimeSteps) : # Axes des courbes du courant : axp = [\ fig.add_axes([d, 0*((1-4*d)/3+d)+d, w1, h1]),\ fig.add_axes([d, 1*((1-4*d)/3+d)+d, w1, h1]),\ fig.add_axes([d, 2*((1-4*d)/3+d)+d, w1, h1])] styles = ['r','b','g'] # axe de la fenêtre principale avec les bobines et les champs axi = fig.add_axes([w1+2*d, d, 1-3*d-w1, 1-2*d]) axi.set_axis_off() # on n'y ajoute pas les axes x1=centerfig[0] y1=centerfig[1] for j in range(0,3): # j : indice de la phase ax=axp[j] ax.axhline(0,color='k') ax.axvline(0,color='k') ax.text(2*np.pi,0.05,'t',color='k') ax.text(0.1,1,'i%d'%(j+1),color=styles[j]) fig.sca(ax) # y = f(alph) : sinusoïde décalée de j*2*pi/3 (j : indice de la phase) y=np.cos(alph-j*2*np.pi/3) xp=i*2*np.pi/numberOfTimeSteps # (xp, yp) : point courant sur la courbe (indiqué avec un cercle) yp=np.cos(xp-j*2*np.pi/3) if drawv[j]: plt.plot(alph,y,styles[j]+'-',xp,yp,styles[j]+'o') fig.sca(axi) dx=VL*yp*np.cos(j*2*np.pi/3) dy=VL*yp*np.sin(-j*2*np.pi/3) #print "%d %d %d %d %d\n" % (j,x1,y1,dx,dy) # Trace du champ créé par la phase if draw_arrows: plt.arrow(x1,y1,dx,dy,color=styles[j],head_width=VHL,head_length=VHL) if compose: x1=x1+dx y1=y1+dy ax.set_xlim(-1.1,2*np.pi+0.1) ax.set_ylim(-1.1,1.1) ax.set_axis_off() # dessin de la boussole if angle_boussole is not None: a = angle_boussole * np.pi /180 + i*2*np.pi/numberOfTimeSteps draw_triangle(axi, a) draw_triangle(axi, a + np.pi, color="white") # Dessin du champ résultant if drawres: x0=centerfig[0] y0=centerfig[1] plt.arrow(x0,y0,x1-x0,y1-y0,color='k',head_width=VHL,head_length=VHL, linewidth=2) fig.sca(axi) imgplot = plt.imshow(img) # # The file name indicates how the image will be saved and the # order it will appear in the movie. If you actually wanted each # graph to be displayed on the screen, you would include commands # such as show() and draw() here. See the matplotlib # documentation for details. In this case, we are saving the # images directly to a file without displaying them. # if AVI_output or GIF_output: filename = str('PartialOut%03d' % i) + '.png' plt.savefig(filename, dpi=100) plt.show() # # Let the user know what's happening. # print 'Wrote file', filename # # Clear the figure to make way for the next image. # plt.clf() # # Now that we have graphed images of the dataset, we will stitch them # together using Mencoder to create a movie. Each image will become # a single frame in the movie. # # We want to use Python to make what would normally be a command line # call to Mencoder. Specifically, the command line call we want to # emulate is (without the initial '#'): # mencoder mf://*.png -mf type=png:w=800:h=600:fps=25 -ovc lavc -lavcopts vcodec=mpeg4 -oac copy -o output.avi # See the MPlayer and Mencoder documentation for details. # if AVI_output: command = ('mencoder', 'mf://PartialOut*.png', '-mf', 'type=png:w=800:h=600:fps=%d'% (fps), '-ovc', 'lavc', '-lavcopts', 'vcodec=mpeg4', '-oac', 'copy', '-o', '%s.avi'%(out_filename)) print "\n\nabout to execute:\n%s\n\n" % ' '.join(command) subprocess.check_call(command) print "\n\n The movie was written to 'output.avi'" if GIF_output: # Ref : http://personal.cscs.ch/~mvalle/postprocessing/ImageTools.html # convert -delay 50 -dispose Background +page Img*.png -loop 0 animation.gif command = ('convert', '-delay', '%d'%(100/fps), '-dispose', 'Background', '+page', 'PartialOut*.png', '-loop', '0', '%s.gif'%(out_filename)) print "\n\nabout to execute:\n%s\n\n" % ' '.join(command) subprocess.check_call(command) print "\n\n The movie was written to '%s'" % out_filename if (AVI_output or GIF_output) and not args.preserve: print "Deleting tempory .png files..." for i in range(numberOfTimeSteps) : filename = str('PartialOut%03d' % i) + '.png' #print "Deleting %s" % filename os.unlink(filename)