在matplotlib中交互式繪製圖像的平均值

Question

我一直在試圖製作一個小工具來動態地使用matplotlib在Python中繪製圖像堆棧的區域平均值。我已經使用了矩形選擇窗口小部件，類似於Persistent rectangle selector

這裏使用的是代碼：

fig, (ax1,ax2) = plt.subplots(2) 
ax1.imshow(im[:100].mean(axis=0)) 
line, =ax2.plot(im.mean(axis=1).mean(axis=1)) 

def line_select_callback(eclick, erelease): 
    global x1, y1 , x2, y2 
    'eclick and erelease are the press and release events' 
    x1, y1 = eclick.xdata, eclick.ydata 
    x2, y2 = erelease.xdata, erelease.ydata 
    print("(%3.2f, %3.2f) --> (%3.2f, %3.2f)" % (x1, y1, x2, y2)) 
    print(" The button you used were: %s %s" % (eclick.button, erelease.button)) 
    verts=np.array([x1, y1, x2, y2],np.uint16) 
    prof=im[:,verts[1]:verts[3],verts[0]:verts[2]].mean(axis=1).mean(axis=1) 
    ax2.plot(prof) 
    ax2.draw() 


def toggle_selector(event): 
    global returned 
    print(' Key pressed.') 
    if event.key in ['Q', 'q'] and toggle_selector.RS.active: 
     print(' RectangleSelector deactivated.') 
     toggle_selector.RS.set_active(False) 
    if event.key in ['A', 'a'] and not toggle_selector.RS.active: 
     print(' RectangleSelector activated.') 
     toggle_selector.RS.set_active(True) 
    if event.key in ['Y', 'y'] and not toggle_selector.RS.active: 
     returned=True 

plt.connect('key_press_event', toggle_selector) 

toggle_selector.RS = RectangleSelector(ax1, line_select_callback, 
              drawtype='box', useblit=True, 
              button=[1, 3], # don't use middle button 
              minspanx=5, minspany=5, 
              spancoords='pixels', 
              interactive=True) 
fig.show() 

我有2個問題與此： 1）當我鬆開情節不會自動更新我的鼠標拖動 2）即使當我釋放鼠標左鍵時，矩形選擇器工具似乎仍然粘在我的鼠標上。

Answer 1

這並不完全清楚它應該在哪個環境下工作。因此，假設您將其作爲腳本運行，您將顯示plt.show()的數字並使用fig.canvas.draw_idle()繪製更新。

import matplotlib.pyplot as plt 
from matplotlib.widgets import RectangleSelector 
import numpy as np 

im = np.random.rand(100,100) 
fig, (ax1,ax2) = plt.subplots(2, gridspec_kw=dict(height_ratios=[5,1])) 
ax1.imshow(im, cmap="summer") 
line, =ax2.plot(im.mean(axis=1)) 

def line_select_callback(eclick, erelease): 
    global x1, y1 , x2, y2 
    'eclick and erelease are the press and release events' 
    x1, y1 = eclick.xdata, eclick.ydata 
    x2, y2 = erelease.xdata, erelease.ydata 
    print("(%3.2f, %3.2f) --> (%3.2f, %3.2f)" % (x1, y1, x2, y2)) 
    print(" The button you used were: %s %s" % (eclick.button, erelease.button)) 
    verts=np.array([x1, y1, x2, y2],np.uint16) 
    prof=im[verts[1]:verts[3],verts[0]:verts[2]].mean(axis=1) 
    line.set_data(np.arange(int(min(y1,y2)), int(max(y1,y2))), prof) 
    fig.canvas.draw_idle() 


def toggle_selector(event): 
    global returned 
    print(' Key pressed.') 
    if event.key in ['Q', 'q'] and toggle_selector.RS.active: 
     print(' RectangleSelector deactivated.') 
     toggle_selector.RS.set_active(False) 
    if event.key in ['A', 'a'] and not toggle_selector.RS.active: 
     print(' RectangleSelector activated.') 
     toggle_selector.RS.set_active(True) 
    if event.key in ['Y', 'y'] and not toggle_selector.RS.active: 
     returned=True 

plt.connect('key_press_event', toggle_selector) 

toggle_selector.RS = RectangleSelector(ax1, line_select_callback, 
              drawtype='box', useblit=True, 
              button=[1, 3], # don't use middle button 
              minspanx=5, minspany=5, 
              spancoords='pixels', 
              interactive=True) 
plt.show()