cairoImageSurfaceCreateForData     package:RGtk2     R Documentation

_c_a_i_r_o_I_m_a_g_e_S_u_r_f_a_c_e_C_r_e_a_t_e_F_o_r_D_a_t_a

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

     Creates an image surface for the provided pixel data. The output
     buffer must be kept around until the 'CairoSurface' is destroyed
     or 'cairoSurfaceFinish' is called on the surface.  The initial
     contents of 'buffer' will be used as the initial image contents;
     you must explicitly clear the buffer, using, for example,
     'cairoRectangle' and 'cairoFill' if you want it cleared.

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

     cairoImageSurfaceCreateForData(data, format, width, height, stride)

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

  'data': [char]  a pointer to a buffer supplied by the application in
          which to write contents. This pointer must be suitably
          aligned for any kind of variable, (for example, a pointer
          returned by malloc).

'format': ['CairoFormat']  the format of pixels in the buffer

 'width': [integer]  the width of the image to be stored in the buffer

'height': [integer]  the height of the image to be stored in the buffer

'stride': [integer]  the number of bytes between the start of rows in
          the buffer as allocated. This value should always be computed
          by 'cairoFormatStrideForWidth' before allocating the data
          buffer.

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

     Note that the stride may be larger than width*bytes_per_pixel to
     provide proper alignment for each pixel and row. This alignment is
     required to allow high-performance rendering within cairo. The
     correct way to obtain a legal stride value is to call
     'cairoFormatStrideForWidth' with the desired format and maximum
     image width value, and the use the resulting stride value to
     allocate the data and to create the image surface. See
     'cairoFormatStrideForWidth' for example code.

_V_a_l_u_e:

     ['CairoSurface']  a pointer to the newly created surface. The
     caller owns the surface and should call 'cairoSurfaceDestroy' when
     done with it.

     This function always returns a valid pointer, but it will return a
     pointer to a "nil" surface in the case of an error such as out of
     memory or an invalid stride value. In case of invalid stride value
     the error status of the returned surface will be
     'CAIRO_STATUS_INVALID_STRIDE'.  You can use 'cairoSurfaceStatus'
     to check for this.

     See 'cairoSurfaceSetUserData' for a means of attaching a
     destroy-notification fallback to the surface if necessary.

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

     Derived by RGtkGen from GTK+ documentation

