electrostatics.py 文件源码

def plot(self, linewidth=None, startarrows=True, endarrows=True):
        """Plots the field line and arrows."""

        if linewidth == None:
            linewidth = matplotlib.rcParams['lines.linewidth']

        x, y = zip(*self.x)
        pyplot.plot(x, y, '-k', linewidth=linewidth)

        n = int(len(x)/2) if len(x) < 225 else 75
        if startarrows:
            pyplot.arrow(x[n], y[n], (x[n+1]-x[n])/100., (y[n+1]-y[n])/100.,
                         fc="k", ec="k",
                         head_width=0.1*linewidth, head_length=0.1*linewidth)

        if len(x) < 225 or not endarrows:
            return

        pyplot.arrow(x[-n], y[-n],
                     (x[-n+1]-x[-n])/100., (y[-n+1]-y[-n])/100.,
                     fc="k", ec="k",
                     head_width=0.1*linewidth, head_length=0.1*linewidth)