adapt test code to draw onto the canvas ina way that DynamicSeries should work

test.py

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+import matplotlib.pyplot as plt
+import numpy as np
+
+x = np.linspace(0, 2 * np.pi, 100)
+
+fig, ax = plt.subplots()
+
+ax.set_xlim(0, 100)
+ax.set_ylim(0, 10000)
+
+# animated=True tells matplotlib to only draw the artist when we
+# explicitly request it
+(ln,) = ax.plot([0,1], [0,1], 'r-', animated=True)
+
+# make sure the window is raised, but the script keeps going
+plt.show(block=False)
+
+# stop to admire our empty window axes and ensure it is rendered at
+# least once.
+#
+# We need to fully draw the figure at its final size on the screen
+# before we continue on so that :
+#  a) we have the correctly sized and drawn background to grab
+#  b) we have a cached renderer so that ``ax.draw_artist`` works
+# so we spin the event loop to let the backend process any pending operations
+plt.pause(0.1)
+ax.draw_artist(ln)
+
+# get copy of entire figure (everything inside fig.bbox) sans animated artist
+bg = fig.canvas.copy_from_bbox(fig.bbox)
+# draw the animated artist, this uses a cached renderer
+ax.draw_artist(ln)
+# show the result to the screen, this pushes the updated RGBA buffer from the
+# renderer to the GUI framework so you can see it
+fig.canvas.blit(fig.bbox)
+
+x_ax = []
+y_ax = []
+
+for j in range(100):
+    # reset the background back in the canvas state, screen unchanged
+    #fig.canvas.restore_region(bg)
+    # update the artist, neither the canvas state nor the screen have changed
+    x_ax.append(j)
+    y_ax.append(j*j)
+
+    ln.set_data([j,j+1], [j*j,(j+1)*(j+1)])
+    # re-render the artist, updating the canvas state, but not the screen
+    ax.draw_artist(ln)
+    # copy the image to the GUI state, but screen might not be changed yet
+    fig.canvas.blit(fig.bbox)
+    # flush any pending GUI events, re-painting the screen if needed
+    fig.canvas.flush_events()
+    # you can put a pause in if you want to slow things down
+    plt.pause(.1)
+
+ax.clear()
+ax.set_xlim(0, 200)
+ax.set_ylim(0, 200*200)
+(ln,) = ax.plot(x_ax, y_ax, 'r-', animated = True)
+plt.pause(0.1)
+ax.draw_artist(ln)
+bg = fig.canvas.copy_from_bbox(fig.bbox)
+fig.canvas.blit(fig.bbox)
+
+for j in range(100, 200):
+    # reset the background back in the canvas state, screen unchanged
+    #fig.canvas.restore_region(bg)
+    # update the artist, neither the canvas state nor the screen have changed
+    x_ax.append(j)
+    y_ax.append(j*j)
+
+    ln.set_data([j,j+1], [j*j,(j+1)*(j+1)])
+    # re-render the artist, updating the canvas state, but not the screen
+    ax.draw_artist(ln)
+    # copy the image to the GUI state, but screen might not be changed yet
+    fig.canvas.blit(fig.bbox)
+    # flush any pending GUI events, re-painting the screen if needed
+    fig.canvas.flush_events()
+    # you can put a pause in if you want to slow things down
+    plt.pause(.1)