func NewSurfaceFromXCB(xcb_drawable xproto.Drawable, xcb_VI xproto.VisualInfo, width, height int) *Surface {
var xcb_visualtype C.xcb_visualtype_t
xcb_visualtype.visual_id = C.xcb_visualid_t(xcb_VI.VisualId)
xcb_visualtype._class = C.uint8_t(xcb_VI.Class)
xcb_visualtype.bits_per_rgb_value = C.uint8_t(xcb_VI.BitsPerRgbValue)
xcb_visualtype.colormap_entries = C.uint16_t(xcb_VI.ColormapEntries)
xcb_visualtype.red_mask = C.uint32_t(xcb_VI.RedMask)
xcb_visualtype.green_mask = C.uint32_t(xcb_VI.GreenMask)
xcb_visualtype.blue_mask = C.uint32_t(xcb_VI.BlueMask)
var connect_xcb (*C.xcb_connection_t) = C.xcb_connect(nil, nil)
s := C.cairo_xcb_surface_create(connect_xcb, C.xcb_drawable_t(xcb_drawable), &xcb_visualtype, C.int(width), C.int(height))
return &Surface{surface: s, context: C.cairo_create(s)}
}
func main() {
// Open connection
c := C.xcb_connect(nil, nil)
// Get first screen
root_iterator := C.xcb_setup_roots_iterator(C.xcb_get_setup(c))
screen := root_iterator.data
// Create black (foreground) graphic context
win := C.xcb_drawable_t(screen.root)
foreground := C.xcb_gcontext_t(C.xcb_generate_id(c))
mask := C.uint32_t(XCB_GC_FOREGROUND) | C.uint32_t(XCB_GC_GRAPHICS_EXPOSURES)
values := []C.uint32_t{screen.black_pixel, 0}
C.xcb_create_gc(c, foreground, win, mask, &values[0])
// Ask for our window's id
win = C.xcb_drawable_t(C.xcb_generate_id(c))
// Create window
mask = C.uint32_t(XCB_CW_BACK_PIXEL) | C.uint32_t(XCB_CW_EVENT_MASK)
values[0] = screen.white_pixel
values[1] = XCB_EVENT_MASK_EXPOSURE
C.xcb_create_window(c, // Connection
XCB_COPY_FROM_PARENT, // depth
C.xcb_window_t(win), // window id
screen.root, // parent
0, 0, // x, y
150, 150, // width, height
10, // border_width
XCB_WINDOW_CLASS_INPUT_OUTPUT, // class
screen.root_visual, // visual
mask, &values[0])
// Map window to screen
C.xcb_map_window(c, C.xcb_window_t(win))
// Flush request
C.xcb_flush(c)
points := []C.xcb_point_t{{10, 10}, {10, 20}, {20, 10}, {20, 20}}
polyline := []C.xcb_point_t{{50, 10}, {5, 20}, {25, -20}, {10, 10}}
segments := []C.xcb_segment_t{{100, 10, 140, 30}, {110, 25, 130, 60}}
rectangles := []C.xcb_rectangle_t{{10, 50, 40, 20}, {80, 50, 10, 40}}
arcs := []C.xcb_arc_t{{10, 100, 60, 40, 0, 90 << 6}, {90, 100, 55, 40, 0, 270 << 6}}
// There must be a better way
for e := C.xcb_wait_for_event(c); e != nil; e = C.xcb_wait_for_event(c) {
switch int(e.response_type) & ^0x80 {
case XCB_EXPOSE:
// Draw points
C.xcb_poly_point(c, XCB_COORD_MODE_ORIGIN, win, foreground, 4, &points[0])
// Draw line
C.xcb_poly_line(c, XCB_COORD_MODE_PREVIOUS, win, foreground, 4, &polyline[0])
// Draw segments
C.xcb_poly_segment(c, win, foreground, 2, &segments[0])
// Draw rectangles
C.xcb_poly_rectangle(c, win, foreground, 2, &rectangles[0])
// Draw arcs
C.xcb_poly_arc(c, win, foreground, 2, &arcs[0])
C.xcb_flush(c)
break
default:
// Unknown
break
}
C.free(unsafe.Pointer(e))
}
}