在 matplotlib 中重绘图形最终会导致 python.exe 崩溃

Question

我是matplotlib 的新手，所以请耐心等待我解释。

我正在使用matplotlib 绘制一个包含一些形状的二维图形。你可以看到下面的代码和输出图：

from random import randint
import matplotlib.path as path
import matplotlib.pyplot as plt
import matplotlib.patches as patches

from matplotlib.pyplot import plot, ion, show
import numpy


box_a_midd_x = 200
box_a_midd_y = -300
box_a_width = 100
box_a_height = 400
box_a_x = box_a_midd_x - box_a_width / 2
box_a_y = box_a_midd_y - box_a_height / 2
box_a = path.Path([(box_a_x, box_a_y), (box_a_x, box_a_y + box_a_height), (box_a_x + box_a_height, box_a_y + box_a_height), (box_a_x + box_a_height, box_a_y)])

box_b_midd_x = 700
box_b_midd_y = 100
box_b_width = 200
box_b_height = 400
box_b_x = box_b_midd_x - box_b_width / 2
box_b_y = box_b_midd_y - box_b_height / 2
box_b = path.Path([(box_b_x, box_b_y), (box_b_x, box_b_y + box_b_height), (box_b_x + box_b_height, box_b_y + box_b_height), (box_b_x + box_b_height, box_b_y)])

box_c_midd_x = 700
box_c_midd_y = 700
box_c_width = 200
box_c_height = 400
box_c_x = box_c_midd_x - box_c_width / 2
box_c_y = box_c_midd_y - box_c_height / 2
box_c = path.Path([(box_c_x, box_c_y), (box_c_x, box_c_y + box_c_height), (box_c_x + box_c_height, box_c_y + box_c_height), (box_c_x + box_c_height, box_c_y)])    

box_d_midd_x = 700
box_d_midd_y = 1400
box_d_width = 200
box_d_height = 400
box_d_x = box_d_midd_x - box_d_width / 2
box_d_y = box_d_midd_y - box_d_height / 2
box_d = path.Path([(box_d_x, box_d_y), (box_d_x, box_d_y + box_d_height), (box_d_x + box_d_height, box_d_y + box_d_height), (box_d_x + box_d_height, box_d_y)])    

monitor_box = path.Path([(35, 1677), (11, -213), (652, -220), (500, 1734)])

print "A: " + str(box_a)
print "B: " + str(box_b)
print "C: " + str(box_c)
print "D: " + str(box_d)

#plt.plot([], [])
#ion()
fig = plt.figure()
ax = fig.add_subplot(111)
patch = patches.PathPatch(monitor_box, facecolor='black', lw=1)
patch_a = patches.PathPatch(box_a, facecolor='orange', lw=2)
patch_b = patches.PathPatch(box_b, facecolor='orange', lw=2)
patch_c = patches.PathPatch(box_c, facecolor='orange', lw=2)
patch_d = patches.PathPatch(box_d, facecolor='orange', lw=2)
ax.add_patch(patch)
ax.add_patch(patch_a)
ax.add_patch(patch_b)
ax.add_patch(patch_c)
ax.add_patch(patch_d)
ax.set_xlim(-2000,2000)
ax.set_ylim(-2000,2000)
plt.gca().invert_yaxis()
#plt.plot([1], [1], 'ro')
#plt.draw()
#plt.show(block=False)
#plt.show()
plt.ion()
xs = [0]
ys = [0]
line, = plt.plot([xs[0], ys[0]], 'ro')
line.set_data(xs, ys)
plt.show()
plt.draw()
plt.pause(0.001)


def update_line(hl, new_data):
    hl.set_xdata(numpy.append(hl.get_xdata(), new_data))
    hl.set_ydata(numpy.append(hl.get_ydata(), new_data))
    plt.draw()



while(True):
    app_x = randint(0,2000)
    app_y = randint(0,2000)

    isInsideA = box_a.contains_points([(app_x,app_y)])
    isInsideB = box_b.contains_points([(app_x,app_y)])
    isInsideC = box_c.contains_points([(app_x,app_y)])
    isInsideD = box_d.contains_points([(app_x,app_y)])
    whichBox = ""
    if isInsideA:
        whichBox = "A"
    elif isInsideB:
        whichBox = "B"
    elif isInsideC:
        whichBox = "C"
    elif isInsideD:
        whichBox = "D"
    else:
        whichBox = "..."

    print ("X: " + str(int(app_x)) + "\t Y: " + str(int(app_y)) + " \t" + str(whichBox))
    xs[0] = int(app_x)
    ys[0] = int(app_y)
    line.set_data(xs, ys)
    plt.show()
    plt.draw()

输出图看起来像这样（真的没什么特别的）。

问题是图表在几秒钟（30-40 秒，而且看起来很随机）后崩溃（Not responsing）。 当图形窗口挂起时，您仍然可以看到 python 代码仍在运行，并且打印了新值，但图形中不再发生任何事情。 我不知道从哪里继续。 请运行上面完整的最小示例，希望您能看到问题。

我在 Windows 7 机器上运行 Python 2.7.8。 更具体地说是 Python 2.7.8（默认，2014 年 6 月 30 日，16:03:49）[MSC v.1500 32 位（英特尔）] 在 win32 上。

Answer 1

def myfunc(x): 返回 hasattr(x, 'set_color')

for o in fig.findobj(myfunc):
    o.set_color('blue')

import matplotlib.text as text

for o in fig.findobj(text.Text):
    o.set_fontstyle('italic')

Answer 2

您为每次迭代创建一个新图。 最好使用 set_data() 并附加到 x 和 y 坐标列表：

plt.ion()
xs = [random.randint(-1000, 1000)]
ys = [random.randint(-1000, 1000)]
line, = plt.plot([xs[0], ys[0]], 'ro')
for _ in range(1000):
    xs.append(random.randint(-1000, 1000))
    ys.append(random.randint(-1000, 1000))
    line.set_data(xs, ys)
    plt.show()
    plt.draw()
    plt.pause(0.001)
plt.ioff()
plt.show()

这是两个列表，每个列表都有一个随机数：

xs = [random.randint(-1000, 1000)]
ys = [random.randint(-1000, 1000)]

现在，使用这些列表创建一个绘图：

line, = plt.plot([xs[0], ys[0]], 'ro')

在循环中，模拟从 LeapMotion 设备获得的新 x 和 y 值并将它们附加到您的坐标：

xs.append(random.randint(-1000, 1000))
ys.append(random.randint(-1000, 1000))

用新坐标更新你的情节：

line.set_data(xs, ys)