Python matplotlib 调用 savefig 后更新图形

Question

我的问题是:我在 PyGTK 应用程序中有 Matplotlib 图，它每隔几秒就会不断更新。我添加了将图形作为 PNG 文件保存到磁盘的功能。调用figure.savefig(文件名，其他参数)后，我在应用程序中的图形停止更新。

图初始化阶段:

# setup matplotlib stuff on empty space in vbox4
    figure = Figure()
    canvas = FigureCanvasGTK(figure) # a gtk.DrawingArea
    canvas.show()
    self.win.get_widget('vbox4').pack_start(canvas, True, True) # this will be aded to last place
    self.win.get_widget('vbox4').reorder_child(canvas, 1) #place plot to space where it should be

图正在以这种方式更新(这在单独的线程中每隔几秒调用一次):

def _updateGraph(self, fig, x, x1, y):
    #Various calculations done here

    fig.clf()#repaint plot: delete current and formate a new one
    axis = fig.add_subplot(111)
    #axis.set_axis_off()
    axis.grid(True)
#remove ticks and labels
    axis.get_xaxis().set_ticks_position("none")
    for i in range(len(axis.get_xticklabels())): axis.get_xticklabels()[i].set_visible(False)
    axis.get_yaxis().set_ticks_position("none")
    axis.plot(numpy.array(x),numpy.array(y)/(1.0**1), "k-" ,alpha=.2)
    axis.set_title('myTitle')
    fig.autofmt_xdate()
    fig.canvas.draw()

一切都按预期进行。但调用后:

figure.savefig(fileName, bbox_inches='tight', pad_inches=0.05)

文件已保存，但屏幕上的图形停止更新。

有什么想法如何将图形保存到磁盘并仍然能够在屏幕上更新我的图形？

Answer 1

您是否尝试过更新线条数据而不是重新创建图形？这假设数据点的数量不会改变每帧。它可能有助于解决拒绝更新的问题，并且至少会更快。

def _updateGraph(self, fig, x, x1, y): 
    #Various calculations done here 


    ydata = numpy.array(y)/(1.0**1)

    # retrieved the saved line object
    line = getattr(fig, 'animated_line', None);

    if line is None:
        # no line object so create the subplot and axis and all 
        fig.clf()
        axis = fig.add_subplot(111) 

        axis.grid(True) 
        #remove ticks and labels 
        axis.get_xaxis().set_ticks_position("none") 
        for i in range(len(axis.get_xticklabels())): 
            axis.get_xticklabels()[i].set_visible(False) 
        axis.get_yaxis().set_ticks_position("none")             
        xdata = numpy.array(x);
        line = axis.plot(xdata, ydata, "k-" ,alpha=.2) 
        axis.set_title('myTitle') 
        fig.autofmt_xdate() 

        # save the line for later reuse
        fig.animated_line = line
    else:
        line.set_ydata(ydata)
    fig.canvas.draw()