blit animation with patches

Community matplotlib-users
1

Hi -
I am wondering how to animate using blit and patches.
The code below was modified from one of the examples.
You will see that it shows (and moves) the rectangle just fine, but
the circle never shows up.
best,
Jaron

import gtk, gobject
import matplotlib
matplotlib.use('GTKAgg') #Agg rendering to a GTK canvas (requires PyGTK)
import numpy as np
import matplotlib.pyplot as plt
from pylab import *
from matplotlib.patches import CirclePolygon

fig = plt.figure(figsize=(14,10))
ax = fig.add_subplot(111, autoscale_on=False )
canvas = fig.canvas

x_start = array([1.0, 2, 2, 1, 1])
y_start = array([1.0, 1, 2, 2, 1])

plt.axis([-1, 7, -0.5, 2.2])

def update_line():
    global x, y
    print update_line.cnt
    if update_line.background is None:
        update_line.background = canvas.copy_from_bbox(ax.bbox)
    canvas.restore_region(update_line.background)
    
    x = x_start + 0.012 * update_line.cnt
    y = y_start + 0.0001 * update_line.cnt
    line, = ax.plot(x, y, animated=True, lw=2)
    ax.draw_artist(line)
    
    x_cir = 1.0 + 0.001*update_line.cnt
    cir = CirclePolygon((x_cir, 1), 0.3, animated=True, resolution=6, lw=2
)
    ax.draw_artist(cir)

    canvas.blit(ax.bbox)

    if update_line.cnt == 10000:
        gtk.mainquit()
        raise SystemExit
    update_line.cnt += 1
    return True

update_line.cnt = 0
update_line.background = None

def start_anim(event):
    gobject.idle_add(update_line)
    canvas.mpl_disconnect(start_anim.cid)

start_anim.cid = canvas.mpl_connect('draw_event', start_anim)

plt.show()

2

Hi -
I am wondering how to animate using blit and patches.
The code below was modified from one of the examples.
You will see that it shows (and moves) the rectangle just fine, but
the circle never shows up.

Artists must be added to the axes -- when you do line, = ax.plot(...)
the Line2D object is added t the Axes. But you never add the circle
to the axes. So do

  cir = CirclePolygon((x_cir, 1), 0.3, animated=True, resolution=6, lw=2)
  ax.add_patch(cir)

and then call

  ax.draw_artist(cir)

when you want to draw it.

JDH

···

On Wed, Feb 10, 2010 at 12:39 PM, John Jameson <jjameson@...2972...> wrote:

best,
Jaron

import gtk, gobject
import matplotlib
matplotlib.use('GTKAgg') #Agg rendering to a GTK canvas (requires PyGTK)
import numpy as np
import matplotlib.pyplot as plt
from pylab import *
from matplotlib.patches import CirclePolygon

fig = plt.figure(figsize=(14,10))
ax = fig.add_subplot(111, autoscale_on=False )
canvas = fig.canvas

x_start = array([1.0, 2, 2, 1, 1])
y_start = array([1.0, 1, 2, 2, 1])

plt.axis([-1, 7, -0.5, 2.2])

def update_line():
global x, y
print update_line.cnt
if update_line.background is None:
update_line.background = canvas.copy_from_bbox(ax.bbox)
canvas.restore_region(update_line.background)

x = x_start + 0.012 * update_line.cnt
y = y_start + 0.0001 * update_line.cnt
line, = ax.plot(x, y, animated=True, lw=2)
ax.draw_artist(line)

x_cir = 1.0 + 0.001*update_line.cnt
cir = CirclePolygon((x_cir, 1), 0.3, animated=True, resolution=6, lw=2
)
ax.draw_artist(cir)

canvas.blit(ax.bbox)

if update_line.cnt == 10000:
gtk.mainquit()
raise SystemExit
update_line.cnt += 1
return True

update_line.cnt = 0
update_line.background = None

def start_anim(event):
gobject.idle_add(update_line)
canvas.mpl_disconnect(start_anim.cid)

start_anim.cid = canvas.mpl_connect('draw_event', start_anim)

plt.show()

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