def TriFill(self, P=[(100, 0, 0), (85, 15, 0), (0, 3, 97)], Color='blue', Alpha=0.3):

        '''
         Fill a region in triangular coord.
        :param P: the peak points of the region in triangular coord
        :type P: a list consist of at least three tuples, which are the points in triangular coord
        :param Color: the color used to fill the region
        :type Color: a string; b: blue, g: green, r: red, c: cyan, m: magenta, y: yellow, k: black, w: white
        :param Alpha: the transparency used to fill the region
        :type Alpha: a float number from 0 to 1, higher darker, lower more transparent
        '''

        a = []
        b = []

        for i in P:
            a.append(self.TriToBin(i[0], i[1], i[2])[0])
            b.append(self.TriToBin(i[0], i[1], i[2])[1])

        return (a, b)
Fill a region in triangular coord.
        :param P: the peak points of the region in triangular coord
        :type P: a list consist of at least three tuples, which are the points in triangular coord
        :param Color: the color used to fill the region
        :type Color: a string; b: blue, g: green, r: red, c: cyan, m: magenta, y: yellow, k: black, w: white
        :param Alpha: the transparency used to fill the region
        :type Alpha: a float number from 0 to 1, higher darker, lower more transparent