RectangleAnim.py

#Draggable Rectangle with blitting
from matplotlib import axes
import numpy as np
import matplotlib.pyplot as plt

class DraggableRectangle:
    lock = None           #only one can be animated at a time


    def __init__(self, rect):
        self.rect = rect
        self.press = None
        self.background = None

    def connect (self):
        """Connect to all the events we need """
        self.cidpress = self.rect.figure.canvas.mpl_connect('button_press_event', self.on_press)
        self.cidrelease = self.rect.figure.canvas.mpl_connect('button_release_event', self.on_release)
        self.cidmotion = self.rect.figure.canvas.mpl_connect('motion_notify_event', self.on_motion)

    def on_press (self, event):
        """check whether mouse is over us; if so, store some data"""
        if (event.inaxes != self.rect.axes
                or DraggableRectangle.lock is not None):
            return
        contains, attrd = self.rect.contains(event)
        if not contains:
            return
        print('event contains', self.rect.xy)
        self.press = self.rect.xy, (event.xdata, event.ydata)
        DraggableRectangle.lock = self

    # Draw everything but the selected rectangle and store the pixel buffer
        canvas = self.rect.figure.canvas
        axes = self.rect.axes
        self.rect.set_animated(True)
        canvas.draw()
        self.background = canvas.copy_from_bbox(self.rect.axes.bbox)

        #now redraw just the rectangle
        axes.draw_artist(self.rect)

        #and blit just the redrawn area
        canvas.blit(axes.bbox)

    def on_motion(self, event):
        """Move the rectangle if the mouse is over us."""
        if (event.inaxes != self.rect.axes
                 or DraggableRectangle.lock is not self):
            return
        (x0, y0), (xpress, ypress) = self.press
        dx = event.xdata - xpress
        dy = event.ydata - ypress
        #print9(f'x0={x0}, xpress={xpress}, event.xdata={event.xdata}, ' f'dx={dx}, x0+dx={x0+dx}')

        self.rect.set_x(x0+dx)
        self.rect.set_y(y0+dy)

        canvas = self.rect.figure.canvas.draw()
        axes = self.rect.axes
        # restore the background region
        canvas.restore_region(self.background)

        # redraw just the current rectangle
        axes.draw_artist(self.rect)

        #blit just the redrawn area
        canvas.blit(axes.bbox)


    def on_release(self, event):
        """Clear button press information."""
        if DraggableRectangle.lock is not self:
            return
        
        self.press = None
        DraggableRectangle.lock = None

        # turn off the rect animation property and reset the background
        self.rect.set_animated(False)
        self.background = None

        # redraw the full figure
        self.rect.figure.canvas.draw()

    def disconnect (self):
        """Disconnect all callbacks"""
        self.rect.figure.canvas.mpl_connect(self.cidpress)
        self.rect.figure.canvass.mpl_connect(self.cidrelease)
        self.rect.figure.canvas.mpl_connect(self.cidmotion)

fig, ax = plt.subplots()
rects = ax.bar(range(10), 20*np.random.rand(10))
drs = []
for rect in rects:
    dr = DraggableRectangle(rect)
    dr.connect()
    drs.append(dr)


plt.show()