[cairo] cairo porting help

[Zoltan Kovacs]

Hi.

I am trying to port the cairo library to an OS that the library does
not support by default. Both libraries (pixman & cairo) has been
compiled successfully and I am trying to test it with the following
code piece:

    int stride = cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, 640);
    dbprintf("stride=%d\n", stride);
    cairo_surface_t* s = cairo_image_surface_create_for_data(
        reinterpret_cast<unsigned char*>(m_graphicsDriver->getFrameBuffer()),
        CAIRO_FORMAT_ARGB32, 640, 480, stride
    );
    cairo_t* cr = cairo_create(s);
    cairo_set_source_rgb(cr, 1, 1, 1);
    cairo_move_to(cr, 0, 0);
    cairo_line_to(cr, 100, 100);
    cairo_paint(cr);

The problem is that it fills the whole framebuffer with white color
instead of drawing just the line. Where should I start debugging to
catch the problem I have?

Thanks,
Zoltan