flush_buffer — Flush the contents of a window.
flush_buffer( : : WindowHandle : )
flush_buffer flushes the contents of the window WindowHandle.
flush_buffer is only necessary if the window parameter 'flush' has been set to 'false' with set_window_param. If 'flush' is 'false' all display operations (such as disp_obj or disp_text) are redirected to a buffer and have no effect on WindowHandle (this applies for all window modes). flush_buffer copies the contents of this buffer to the window WindowHandle.
This is very useful to avoid flickering by batching several display operations (e.g. a clear_window followed by a disp_obj) and displaying the final result with flush_buffer.
This does not apply to drawing objects, which are always updated.
flush_buffer depends on the library libcanvas, which might not be available on embedded systems.
read_image (Image, 'printer_chip/printer_chip_01') threshold (Image, Region, 128, 255) dev_open_window (0, 0, 512, 512, 'black', WindowHandle) set_window_param (WindowHandle, 'flush', 'false') dev_display (Image) dev_display (Region) disp_text (WindowHandle, 'Result of threshold', 'window', \ 12, 12, 'black', , ) * nothing is displayed until flush_buffer is called flush_buffer (WindowHandle)
If the window exists flush_buffer returns 2 (H_MSG_TRUE).