rem     **** LINE TANGENT TO CIRCLE AT ANGLE ****

:arc
        window @xmin,@ymin,@xmax,@ymax

        set mask, 3
        getent "SELECT ARC ", entype
        if (@key < -1)
                goto exit
        if (@key == -1)
                goto exit

        basex = @xworld
        basey = @yworld

        X = @fltdat[0]
        Y = @fltdat[1]
        R = @fltdat[3]

:menu
        getmenu "SELECT ANGLE","0°","45°","90°","135°","180°","225°","270°","315°","KEY-IN",
        if (@key ==-3)
                goto exit
        if (@key ==-2)
                goto exit
        if (@key ==-1)
                goto menu
        if (@key ==1)
                goto deg0
        if (@key ==2)
                goto deg45
        if (@key ==3)
                goto deg90
        if (@key ==4)
                goto deg135
        if (@key ==5)
                goto deg180
        if (@key ==6)
                goto deg225
        if (@key ==7)
                goto deg270
        if (@key ==8)
                goto deg315
        if (@key ==9)
                goto degun

:deg0
        if (@key ==-3)
                goto menu
        if (@key ==-2)
                goto menu
        if (@key ==-1)
                goto deg0

        line @FLTDAT[0]+R, @FLTDAT[1]-R, 0, @FLTDAT[0]+R, @FLTDAT[1]+R, 0
                goto arc


:deg90
        if (@key ==-3)
                goto menu
        if (@key ==-2)
                goto menu
        if (@key ==-1)
                goto deg90

        line @FLTDAT[0]-R, @FLTDAT[1]+R, 0, @FLTDAT[0]+R, @FLTDAT[1]+R, 0
                goto arc


:deg180
        if (@key ==-3)
                goto menu
        if (@key ==-2)
                goto menu
        if (@key ==-1)
                goto deg180

        line @FLTDAT[0]-R, @FLTDAT[1]-R, 0, @FLTDAT[0]-R, @FLTDAT[1]+R, 0
                goto arc

:deg270
        if (@key ==-3)
                goto menu
        if (@key ==-2)
                goto menu
        if (@key ==-1)
                goto deg270

        line @FLTDAT[0]-R, @FLTDAT[1]-R, 0, @FLTDAT[0]+R, @FLTDAT[1]-R, 0
                goto arc

:degun
        def = 0.0
        getflt "ENTER ANGLE VALUE => ", def, ang1
        a=cos(ang1)*R
        b=sin(ang1)*R
        c=sqrt(R^2+R^2)
        px1 = X + a
        py1 = Y + b
        px2 = X
        py2 = c
        d=sin(ang1)*R
        e=cos(ang1)*R
              goto degun1

:degun1
        if (@key ==-3)
                goto menu
        if (@key ==-2)
                goto menu
        if (@key ==-1)
                goto degun

        line px1+d, py1-e, 0, px1-d, py1+e, 0
                goto arc

:deg45
        a=cos(45)*R
        b=sin(45)*R
        c=R/sin(45)
        px1 = X + a
        py1 = Y + b
        px2 = X
        py2 = c
        if (@key ==-3)
                goto menu
        if (@key ==-2)
                goto menu
        if (@key ==-1)
                goto deg45

        line px1-R, py1+R, 0, px1+R, py1-R, 0
                goto arc

:deg135
        a=cos(45)*R
        b=sin(45)*R
        c=R/sin(45)
        px1 = X - a
        py1 = Y + b
        px2 = X
        py2 = c
        if (@key ==-3)
                goto menu
        if (@key ==-2)
                goto menu
        if (@key ==-1)
                goto deg135

        line px1-R, py1-R, 0, px1+R, py1+R, 0
                goto arc

:deg225
        a=cos(45)*R
        b=sin(45)*R
        c=R/sin(45)
        px1 = X - a
        py1 = Y - b
        px2 = X
        py2 = c
        if (@key ==-3)
                goto menu
        if (@key ==-2)
                goto menu
        if (@key ==-1)
                goto deg225

        line px1-R, py1+R, 0, px1+R, py1-R, 0
                goto arc
:deg315
        a=cos(45)*R
        b=sin(45)*R
        c=R/sin(45)
        px1 = X + a
        py1 = Y - b
        px2 = X
        py2 = c
        if (@key ==-3)
                goto menu
        if (@key ==-2)
                goto menu
        if (@key ==-1)
                goto deg315

        line px1-R, py1-R, 0, px1+R, py1+R, 0
                goto arc

:exit
        redraw
        exit