cairoArc                package:RGtk2                R Documentation

_c_a_i_r_o_A_r_c

_D_e_s_c_r_i_p_t_i_o_n:

     Adds a circular arc of the given 'radius' to the current path. 
     The arc is centered at ('xc', 'yc'), begins at 'angle1' and
     proceeds in the direction of increasing angles to end at 'angle2'.
     If 'angle2' is less than 'angle1' it will be progressively
     increased by 2*M_PI until it is greater than 'angle1'.

_U_s_a_g_e:

     cairoArc(cr, xc, yc, radius, angle1, angle2)

_A_r_g_u_m_e_n_t_s:

    'cr': ['Cairo']  a cairo context

    'xc': [numeric]  X position of the center of the arc

    'yc': [numeric]  Y position of the center of the arc

'radius': [numeric]  the radius of the arc

'angle1': [numeric]  the start angle, in radians

'angle2': [numeric]  the end angle, in radians

_D_e_t_a_i_l_s:

     If there is a current point, an initial line segment will be added
     to the path to connect the current point to the beginning of the
     arc.

     Angles are measured in radians. An angle of 0 is in the direction
     of the positive X axis (in user-space). An angle of 'M_PI' radians
     (90 degrees) is in the direction of the positive Y axis (in
     user-space). Angles increase in the direction from the positive X
     axis toward the positive Y axis. So with the default
     transformation matrix, angles increase in a clockwise direction.

     (To convert from degrees to radians, use 'degrees * (M_PI /
     180.)'.)

     This function gives the arc in the direction of increasing angles;
     see 'cairoArcNegative' to get the arc in the direction of
     decreasing angles.

     The arc is circular in user-space. To achieve an elliptical arc,
     you can scale the current transformation matrix by different
     amounts in the X and Y directions. For example, to draw an ellipse
     in the box given by 'x', 'y', 'width', 'height':


     cr$save()
     cr$translate(x + width / 2, y + height / 2)
     cr$scale(1 / (height / 2), 1 / (width / 2))
     cr$arc(0, 0, 1, 0, 2 * pi)
     cr$restore()


_A_u_t_h_o_r(_s):

     Derived by RGtkGen from GTK+ documentation

