code: func ReadnPixels(x int32, y int32, width int32, height int32, format uint32, xtype uint32, bufSize int32, data unsafe.Pointer) {
  	syscall.Syscall9(gpReadnPixels, 8, uintptr(x), uintptr(y), uintptr(width), uintptr(height), uintptr(format), uintptr(xtype), uintptr(bufSize), uintptr(data), 0)
  }
docs: // read a block of pixels from the frame buffer