transfer_functions.py 文件源码

def show(self, ax=None):
        r"""Display an image of the transfer function

        This function loads up matplotlib and displays the current transfer function.

        Parameters
        ----------

        Examples
        --------

        >>> tf = TransferFunction( (-10.0, -5.0) )
        >>> tf.add_gaussian(-9.0, 0.01, 1.0)
        >>> tf.show()
        """
        from matplotlib import pyplot
        from matplotlib.ticker import FuncFormatter
        pyplot.clf()
        ax = pyplot.axes()
        i_data = np.zeros((self.alpha.x.size, self.funcs[0].y.size, 3))
        i_data[:,:,0] = np.outer(np.ones(self.alpha.x.size), self.funcs[0].y)
        i_data[:,:,1] = np.outer(np.ones(self.alpha.x.size), self.funcs[1].y)
        i_data[:,:,2] = np.outer(np.ones(self.alpha.x.size), self.funcs[2].y)
        ax.imshow(i_data, origin='lower')
        ax.fill_between(np.arange(self.alpha.y.size), self.alpha.x.size * self.alpha.y, y2=self.alpha.x.size, color='white')
        ax.set_xlim(0, self.alpha.x.size)
        xticks = np.arange(np.ceil(self.alpha.x[0]), np.floor(self.alpha.x[-1]) + 1, 1) - self.alpha.x[0]
        xticks *= (self.alpha.x.size-1) / (self.alpha.x[-1] - self.alpha.x[0])
        if len(xticks) > 5:
            xticks = xticks[::len(xticks)/5]
        ax.xaxis.set_ticks(xticks)
        def x_format(x, pos):
            return "%.1f" % (x * (self.alpha.x[-1] - self.alpha.x[0]) / (self.alpha.x.size-1) + self.alpha.x[0])
        ax.xaxis.set_major_formatter(FuncFormatter(x_format))
        yticks = np.linspace(0,1,5) * self.alpha.y.size
        ax.yaxis.set_ticks(yticks)
        def y_format(y, pos):
            s = '%0.2f' % ( y )
            return s
        ax.yaxis.set_major_formatter(FuncFormatter(y_format))
        ax.set_ylabel("Opacity")
        ax.set_xlabel("Value")