%matplotlib notebook

# JR 6/21/14
# Reimplementation of my java phase plane draw in python/pylab.
# Idea from Interactive Differential Equations.
# Works pretty well.
# Don't see how to get the t curves to keep drawing 
# when pointer stationary and hence not generating events.
# Not a major problem, though.

from pylab import *
from time import time
import numpy as np

tmax = 20. # in seconds. Time starts on first click.
nt = 10    # number of t-grid intervals

xycurves = {}
xtcurves = {}
tycurves = {}

figure(figsize=(8,8))
xyax = axes([ 0,.5,.5,.5])#,aspect=1)
xtax = axes([ 0, 0,.5,.5])
tyax = axes([.5,.5,.5,.5])

def move(event):
	global tstart,x,y,t,xycurves,tycurves,xyinv
	if buttonisdown:
		ux,uy = xyinv.transform( (event.x,event.y) )
		x.append(ux)
		y.append(uy)
		t.append( (time() - tstart) ) 
		xycurves[ncurves].set_xdata(x)
		xycurves[ncurves].set_ydata(y)
		tycurves[ncurves].set_xdata(t)
		tycurves[ncurves].set_ydata(y)
		xtcurves[ncurves].set_xdata(x)
		xtcurves[ncurves].set_ydata(t)
		draw()

def press(event):
	global started,tstart,buttonisdown,x,y,t,xycurves,tycurves,xyinv
	xyinv = xyax.transData.inverted()  # function to convert from pixels to user coordinates

	ux,uy = xyinv.transform( (event.x,event.y) )
	x = [ux]
	y = [uy]
	
	if not started: 
		tstart = time()
		started = True
	eventt = time() - tstart
	t = [eventt]	
	xycurves[ncurves], = xyax.plot(x,y)
	tycurves[ncurves], = tyax.plot(t,y)
	xtcurves[ncurves], = xtax.plot(x,t)
	buttonisdown = True

def release(event):
	global buttonisdown,ncurves
	xyinv = xyax.transData.inverted()  # function to convert from pixels to user coordinates
	move(event) # to get last point drawn
	ncurves += 1
	buttonisdown = False

connect('motion_notify_event' , move   )
connect('button_press_event'  , press  )
connect('button_release_event', release)

started = False
buttonisdown = False
ncurves = 0

alpha = 0.9
xyax.plot( [-1,  1], [ 0,   0], 'm', alpha=alpha); xyax.text(     .93 ,     -.08, 'x', color='m')
xyax.plot( [ 0,  0], [-1,   1], 'b', alpha=alpha); xyax.text(     .02 ,      .9 , 'y', color='b')
tyax.plot( [0,tmax], [ 0,   0], 'k', alpha=alpha); tyax.text(tmax*.97 ,     -.08, 't', color='k')
tyax.plot( [ 0,  0], [-1,   1], 'b', alpha=alpha); tyax.text(tmax*.01 ,      .9 , 'y', color='b')
xtax.plot( [0,   0], [ 0,tmax], 'k', alpha=alpha); xtax.text(     .02 , tmax*.99, 't', color='k')
xtax.plot( [-1,  1], [ 0,   0], 'm', alpha=alpha); xtax.text(     .93 , tmax*.04, 'x', color='m')

for t in np.linspace(0,tmax,nt+1):
	tyax.plot([ t,t],[-1,1],'b',alpha=0.2)
	xtax.plot([-1,1],[ t,t],'m',alpha=0.2)

xyax.set_xlim(-1,1)
xyax.set_ylim(-1,1)
xyinv = xyax.transData.inverted()  # function to convert from pixels to user coordinates
tyax.set_xlim(0,tmax)
tyax.set_ylim(-1,1)
xtax.set_xlim(-1,1)
xtax.set_ylim(tmax,0)

xyax.set_xticks([])
xyax.set_yticks([])
tyax.set_xticks([])
tyax.set_yticks([])
xtax.set_xticks([])
xtax.set_yticks([])

print("Draw in upper-left panel")