Get common parameters for making line end symbols.

def _le_annot_parms(self, annot, p1, p2):
        """Get common parameters for making line end symbols.
        """
        w = annot.border["width"]          # line width
        sc = annot.colors["stroke"]        # stroke color
        if not sc: sc = (0,0,0)
        scol = " ".join(map(str, sc)) + " RG\n"
        fc = annot.colors["fill"]          # fill color
        if not fc: fc = (0,0,0)
        fcol = " ".join(map(str, fc)) + " rg\n"
        nr = annot.rect
        np1 = p1                   # point coord relative to annot rect
        np2 = p2                   # point coord relative to annot rect
        m = self._hor_matrix(np1, np2)        # matrix makes the line horizontal
        im = ~m                            # inverted matrix
        L = np1 * m                        # converted start (left) point
        R = np2 * m                        # converted end (right) point
        if 0 <= annot.opacity < 1:
            opacity = "/Alp0 gs\n"
        else:
            opacity = ""
        return m, im, L, R, w, scol, fcol, opacity