Method get_quiver_arrows

plotly/figure_factory/_quiver.py:196–265

Creates lists of x and y values to plot the arrows Gets length of each barb then calculates the length of each side of the arrow. Gets angle of barb and applies angle to each side of the arrowhead. Next uses arrow_scale to scale the length of arrowhead and c

(self)

        return barb_x, barb_y

    def get_quiver_arrows(self):
        """
        Creates lists of x and y values to plot the arrows

        Gets length of each barb then calculates the length of each side of
        the arrow. Gets angle of barb and applies angle to each side of the
        arrowhead. Next uses arrow_scale to scale the length of arrowhead and
        creates x and y values for arrowhead point1 and point2. Finally x and y
        values for point1, endpoint and point2s for each arrowhead are
        separated by a None and zipped to create lists of x and y values for
        the arrows.

        :rtype: (list, list) arrow_x, arrow_y: list of point1, endpoint, point2
            x_values separated by a None to create the arrowhead and list of
            point1, endpoint, point2 y_values separated by a None to create
            the barb of the arrow.
        """
        dif_x = [i - j for i, j in zip(self.end_x, self.x)]
        dif_y = [i - j for i, j in zip(self.end_y, self.y)]

        # Get barb lengths(default arrow length = 30% barb length)
        barb_len = [None] * len(self.x)
        for index in range(len(barb_len)):
            barb_len[index] = math.hypot(dif_x[index] / self.scaleratio, dif_y[index])

        # Make arrow lengths
        arrow_len = [None] * len(self.x)
        arrow_len = [i * self.arrow_scale for i in barb_len]

        # Get barb angles
        barb_ang = [None] * len(self.x)
        for index in range(len(barb_ang)):
            barb_ang[index] = math.atan2(dif_y[index], dif_x[index] / self.scaleratio)

        # Set angles to create arrow
        ang1 = [i + self.angle for i in barb_ang]
        ang2 = [i - self.angle for i in barb_ang]

        cos_ang1 = [None] * len(ang1)
        for index in range(len(ang1)):
            cos_ang1[index] = math.cos(ang1[index])
        seg1_x = [i * j for i, j in zip(arrow_len, cos_ang1)]

        sin_ang1 = [None] * len(ang1)
        for index in range(len(ang1)):
            sin_ang1[index] = math.sin(ang1[index])
        seg1_y = [i * j for i, j in zip(arrow_len, sin_ang1)]

        cos_ang2 = [None] * len(ang2)
        for index in range(len(ang2)):
            cos_ang2[index] = math.cos(ang2[index])
        seg2_x = [i * j for i, j in zip(arrow_len, cos_ang2)]

        sin_ang2 = [None] * len(ang2)
        for index in range(len(ang2)):
            sin_ang2[index] = math.sin(ang2[index])
        seg2_y = [i * j for i, j in zip(arrow_len, sin_ang2)]