How to update plot without redraw figure

I draw grid inside a circle, and when I pick any grid, I will add a rectangle object to circle. But when the grid number is large(over 40000) and there are many rectangles have been added, the plot figure time would be very long.

I think that is because every time I add rectangle I will redraw the figure.
So I think if I can just update figure and not to redraw it, it will be much faster. But, unfortunately, I can not find any api to do it in matplotlib. Does anybody have any idea to solve this problem ? Thank you !

Here's part of my code :

import matplotlib.pyplot as plt

import matplotlib.patches as patches

import numpy as np



def onclick(event):

    """add Rectangle when click any gird on circle"""

    try:

        rect = patches.Rectangle((int(event.mouseevent.xdata), int(event.mouseevent.ydata)), 1, 1, facecolor=(.7, .9, .9, .9), edgecolor=(.2, .1, .1,.5))

        ax.add_patch(rect)

        rect.set_clip_path(circ)

        # redraw can update the figure, but it would take long time

        fig.canvas.draw()

    except Exception as e:

        print(e.args)





r = 50  # radius

fig = plt.figure()

ax = plt.gca()

plt.grid(True)



circ = patches.Circle((0, 0), radius=r,

                      facecolor=(.5, .5, .5), edgecolor='black', picker=5)

ax.add_patch(circ)



# Fill half of circle with rectagles

for x in range(int(-r/2), int(r/2)):

    for y in range(int(-r/2), int(r/2)):

        if x + y < r * r:

            rect = patches.Rectangle((x, y), 1, 1, facecolor=(.7, .5, .5, .5), edgecolor=(.2, .1, .1, .5))

            ax.add_patch(rect)

            rect.set_clip_path(circ)



fig.canvas.mpl_connect('pick_event', onclick)



# Diable any ticks and labels

plt.tick_params(

    axis='both',

    left='off',

    bottom='off',

    labelleft='off',

    labelbottom='off'

)

plt.xlim([-r-1, r+1])

plt.ylim([-r-1, r+1])

plt.xticks(np.arange(-r-1, r+1))

plt.yticks(np.arange(-r-1, r+1))

plt.setp(ax.xaxis.get_gridlines(), clip_path=circ)

plt.setp(ax.yaxis.get_gridlines(), clip_path=circ)



plt.axes().set_aspect('equal')

plt.show()

edited Jan 2 at 3:33

asked Jan 2 at 3:14

Lester_wu

815

"Update" and "redraw" are the same things in this case. You may however try to blit the new rectangle onto the canvas. Before doing that I would first try to not add individual rectangles though, but instead work with a single PolyCollection with as many shapes as you need.

– ImportanceOfBeingErnest
Jan 2 at 10:52

Thanks for your advise. I'll try to use PolyCollection to see if it works.

– Lester_wu
Jan 3 at 1:27

add a comment |

Here's part of my code :

import matplotlib.pyplot as plt

import matplotlib.patches as patches

import numpy as np



def onclick(event):

    """add Rectangle when click any gird on circle"""

    try:

        rect = patches.Rectangle((int(event.mouseevent.xdata), int(event.mouseevent.ydata)), 1, 1, facecolor=(.7, .9, .9, .9), edgecolor=(.2, .1, .1,.5))

        ax.add_patch(rect)

        rect.set_clip_path(circ)

        # redraw can update the figure, but it would take long time

        fig.canvas.draw()

    except Exception as e:

        print(e.args)





r = 50  # radius

fig = plt.figure()

ax = plt.gca()

plt.grid(True)



circ = patches.Circle((0, 0), radius=r,

                      facecolor=(.5, .5, .5), edgecolor='black', picker=5)

ax.add_patch(circ)



# Fill half of circle with rectagles

for x in range(int(-r/2), int(r/2)):

    for y in range(int(-r/2), int(r/2)):

        if x + y < r * r:

            rect = patches.Rectangle((x, y), 1, 1, facecolor=(.7, .5, .5, .5), edgecolor=(.2, .1, .1, .5))

            ax.add_patch(rect)

            rect.set_clip_path(circ)



fig.canvas.mpl_connect('pick_event', onclick)



# Diable any ticks and labels

plt.tick_params(

    axis='both',

    left='off',

    bottom='off',

    labelleft='off',

    labelbottom='off'

)

plt.xlim([-r-1, r+1])

plt.ylim([-r-1, r+1])

plt.xticks(np.arange(-r-1, r+1))

plt.yticks(np.arange(-r-1, r+1))

plt.setp(ax.xaxis.get_gridlines(), clip_path=circ)

plt.setp(ax.yaxis.get_gridlines(), clip_path=circ)



plt.axes().set_aspect('equal')

plt.show()

edited Jan 2 at 3:33

asked Jan 2 at 3:14

Lester_wu

815

"Update" and "redraw" are the same things in this case. You may however try to blit the new rectangle onto the canvas. Before doing that I would first try to not add individual rectangles though, but instead work with a single PolyCollection with as many shapes as you need.

– ImportanceOfBeingErnest
Jan 2 at 10:52

Thanks for your advise. I'll try to use PolyCollection to see if it works.

– Lester_wu
Jan 3 at 1:27

add a comment |

Here's part of my code :

import matplotlib.pyplot as plt

import matplotlib.patches as patches

import numpy as np



def onclick(event):

    """add Rectangle when click any gird on circle"""

    try:

        rect = patches.Rectangle((int(event.mouseevent.xdata), int(event.mouseevent.ydata)), 1, 1, facecolor=(.7, .9, .9, .9), edgecolor=(.2, .1, .1,.5))

        ax.add_patch(rect)

        rect.set_clip_path(circ)

        # redraw can update the figure, but it would take long time

        fig.canvas.draw()

    except Exception as e:

        print(e.args)





r = 50  # radius

fig = plt.figure()

ax = plt.gca()

plt.grid(True)



circ = patches.Circle((0, 0), radius=r,

                      facecolor=(.5, .5, .5), edgecolor='black', picker=5)

ax.add_patch(circ)



# Fill half of circle with rectagles

for x in range(int(-r/2), int(r/2)):

    for y in range(int(-r/2), int(r/2)):

        if x + y < r * r:

            rect = patches.Rectangle((x, y), 1, 1, facecolor=(.7, .5, .5, .5), edgecolor=(.2, .1, .1, .5))

            ax.add_patch(rect)

            rect.set_clip_path(circ)



fig.canvas.mpl_connect('pick_event', onclick)



# Diable any ticks and labels

plt.tick_params(

    axis='both',

    left='off',

    bottom='off',

    labelleft='off',

    labelbottom='off'

)

plt.xlim([-r-1, r+1])

plt.ylim([-r-1, r+1])

plt.xticks(np.arange(-r-1, r+1))

plt.yticks(np.arange(-r-1, r+1))

plt.setp(ax.xaxis.get_gridlines(), clip_path=circ)

plt.setp(ax.yaxis.get_gridlines(), clip_path=circ)



plt.axes().set_aspect('equal')

plt.show()

edited Jan 2 at 3:33

asked Jan 2 at 3:14

Lester_wu

815

Here's part of my code :

import matplotlib.pyplot as plt

import matplotlib.patches as patches

import numpy as np



def onclick(event):

    """add Rectangle when click any gird on circle"""

    try:

        rect = patches.Rectangle((int(event.mouseevent.xdata), int(event.mouseevent.ydata)), 1, 1, facecolor=(.7, .9, .9, .9), edgecolor=(.2, .1, .1,.5))

        ax.add_patch(rect)

        rect.set_clip_path(circ)

        # redraw can update the figure, but it would take long time

        fig.canvas.draw()

    except Exception as e:

        print(e.args)





r = 50  # radius

fig = plt.figure()

ax = plt.gca()

plt.grid(True)



circ = patches.Circle((0, 0), radius=r,

                      facecolor=(.5, .5, .5), edgecolor='black', picker=5)

ax.add_patch(circ)



# Fill half of circle with rectagles

for x in range(int(-r/2), int(r/2)):

    for y in range(int(-r/2), int(r/2)):

        if x + y < r * r:

            rect = patches.Rectangle((x, y), 1, 1, facecolor=(.7, .5, .5, .5), edgecolor=(.2, .1, .1, .5))

            ax.add_patch(rect)

            rect.set_clip_path(circ)



fig.canvas.mpl_connect('pick_event', onclick)



# Diable any ticks and labels

plt.tick_params(

    axis='both',

    left='off',

    bottom='off',

    labelleft='off',

    labelbottom='off'

)

plt.xlim([-r-1, r+1])

plt.ylim([-r-1, r+1])

plt.xticks(np.arange(-r-1, r+1))

plt.yticks(np.arange(-r-1, r+1))

plt.setp(ax.xaxis.get_gridlines(), clip_path=circ)

plt.setp(ax.yaxis.get_gridlines(), clip_path=circ)



plt.axes().set_aspect('equal')

plt.show()

python-3.x matplotlib

edited Jan 2 at 3:33

asked Jan 2 at 3:14

Lester_wu

815

edited Jan 2 at 3:33

asked Jan 2 at 3:14

Lester_wu

815

edited Jan 2 at 3:33

asked Jan 2 at 3:14

Lester_wu

815

asked Jan 2 at 3:14

Lester_wu

815

asked Jan 2 at 3:14

Lester_wu

815

"Update" and "redraw" are the same things in this case. You may however try to blit the new rectangle onto the canvas. Before doing that I would first try to not add individual rectangles though, but instead work with a single PolyCollection with as many shapes as you need.

– ImportanceOfBeingErnest
Jan 2 at 10:52

Thanks for your advise. I'll try to use PolyCollection to see if it works.

– Lester_wu
Jan 3 at 1:27

add a comment |

"Update" and "redraw" are the same things in this case. You may however try to blit the new rectangle onto the canvas. Before doing that I would first try to not add individual rectangles though, but instead work with a single PolyCollection with as many shapes as you need.

– ImportanceOfBeingErnest
Jan 2 at 10:52

Thanks for your advise. I'll try to use PolyCollection to see if it works.

– Lester_wu
Jan 3 at 1:27

"Update" and "redraw" are the same things in this case. You may however try to blit the new rectangle onto the canvas. Before doing that I would first try to not add individual rectangles though, but instead work with a single PolyCollection with as many shapes as you need.

– ImportanceOfBeingErnest
Jan 2 at 10:52

Thanks for your advise. I'll try to use PolyCollection to see if it works.

– Lester_wu
Jan 3 at 1:27

add a comment |

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