Question

从下面显示的工作Matplotlib动画代码开始，我的目标是在PyQT4 GUI中嵌入这个动画（这只是一个在屏幕上移动的圆圈）。

import matplotlib.pyplot as plt
from matplotlib.patches import Circle
from matplotlib import animation

fig,ax = plt.subplots()
ax.set_aspect('equal','box')
circle = Circle((0,0), 1.0)
ax.add_artist(circle)
ax.set_xlim([0,10])
ax.set_ylim([-2,2])

def animate(i):
    circle.center=(i,0)
    return circle, 

anim = animation.FuncAnimation(fig,animate,frames=10,interval=100,repeat=False,blit=True)

plt.show()

我可以使用以下代码完成此操作，但有一个障碍：我无法工作。

import sys
from PyQt4 import QtGui, QtCore
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure
from matplotlib.patches import Circle
from matplotlib import animation

class Window(QtGui.QDialog): #or QtGui.QWidget ???

    def __init__(self):
        super(Window, self).__init__()
        self.fig = Figure(figsize=(5,4),dpi=100)
        self.canvas = FigureCanvas(self.fig)
        self.ax = self.fig.add_subplot(111)  # create an axis
        self.ax.hold(False)  # discards the old graph
        self.ax.set_aspect('equal','box')
        self.circle = Circle((0,0), 1.0)
        self.ax.add_artist(self.circle)
        self.ax.set_xlim([0,10])
        self.ax.set_ylim([-2,2])
        self.button = QtGui.QPushButton('Animate')
        self.button.clicked.connect(self.animate)

        # set the layout
        layout = QtGui.QVBoxLayout()
        layout.addWidget(self.canvas)
        layout.addWidget(self.button)
        self.setLayout(layout)

    def animate(self):
        self.anim = animation.FuncAnimation(self.fig,self.animate_loop,frames=10,interval=100,repeat=False,blit=False)
        self.canvas.draw()

    def animate_loop(self,i):
        self.circle.center=(i,0)
        return self.circle, 

def main():

    app = QtGui.QApplication(sys.argv)
    ex = Window()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()

当我设置blit=True时，按下Animate按钮后，我收到以下错误：的 a.figure.canvas.restore_region（bg_cache [A]） KeyError：位于0x00000000095F1D30的matplotlib.axes._subplots.AxesSubplot对象

在搜索此错误时，我发现很多关于blits如何在Mac上不起作用的帖子，但我使用的是Windows 7.我尝试用self.canvas.draw()替换self.canvas.update()，但这不起作用。

Answer 1

在查看动画模块的源代码之后，我意识到Animation类中存在错误（字典bg_cache为空，当第一次访问它时打开blitting）。

这是在matplotlib的git版本中修复的;但是，在最新的稳定版本1.5.1中，该错误仍然存在。您可以修复matplotlib代码本身的错误，也可以创建FuncAnimation的子类。我选择了这种方式，因为它在更新matplotlib之后仍然可以工作。

from matplotlib import animation

class MyFuncAnimation(animation.FuncAnimation):
    """
    Unfortunately, it seems that the _blit_clear method of the Animation
    class contains an error in several matplotlib verions
    That's why, I fork it here and insert the latest git version of
    the function.
    """
    def _blit_clear(self, artists, bg_cache):
        # Get a list of the axes that need clearing from the artists that
        # have been drawn. Grab the appropriate saved background from the
        # cache and restore.
        axes = set(a.axes for a in artists)
        for a in axes:
            if a in bg_cache: # this is the previously missing line
                a.figure.canvas.restore_region(bg_cache[a])

然后，简单地使用MyFuncAnimation而不是animation.FuncAnimation。

我花了一些时间来弄明白，但我希望它可以帮助任何人。

Answer 2

一段时间后，我设法通过直接使用底层函数重新创建动画，而不是使用动画包装器：

import sys
from PyQt4 import QtGui, QtCore
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure
from matplotlib.patches import Circle
from matplotlib import animation
from time import sleep

class Window(QtGui.QDialog): #or QtGui.QWidget ???

    def __init__(self):
        super(Window, self).__init__()
        self.fig = Figure(figsize=(5, 4), dpi=100)
        self.canvas = FigureCanvas(self.fig)
        self.ax = self.fig.add_subplot(111)  # create an axis
        self.ax.hold(False)  # discards the old graph
        self.ax.set_aspect('equal', 'box')
        self.circle = Circle((0,0), 1.0, animated=True)
        self.ax.add_artist(self.circle)
        self.ax.set_xlim([0, 10])
        self.ax.set_ylim([-2, 2])
        self.button = QtGui.QPushButton('Animate')
        self.button.clicked.connect(self.animate)

        # set the layout
        layout = QtGui.QVBoxLayout()
        layout.addWidget(self.canvas)
        layout.addWidget(self.button)
        self.setLayout(layout)
        self.canvas.draw()
        self.ax_background = self.canvas.copy_from_bbox(self.ax.bbox)

    def animate(self):
        self.animate_loop(0)

    def animate_loop(self,i):
        for i in range(10):
            self.canvas.restore_region(self.ax_background)
            self.circle.center=(i,0)
            self.ax.draw_artist(self.circle)
            self.canvas.blit(self.ax.bbox)
            self.canvas.flush_events()
            sleep(0.1)

def main():

    app = QtGui.QApplication(sys.argv)
    ex = Window()
    ex.show()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()

也许这会对你有用。

让blitting在PyQT4 GUI中嵌入的funcAnimation中工作

2 个答案: