window. May also be used to set a
background of "None" on window, by setting a background pixmap
of NULL.gdkWindowSetBackPixmap(object, pixmap = NULL, parent.relative)objectpixmapGdkPixmap, or NULL. [ allow-none ]parent.relativewindow's parentwindow, or if parent.relative is TRUE, the tiling
will be done based on the origin of the parent window (useful to
align tiles in a parent with tiles in a child).
A background pixmap of NULL means that the window will have no
background. A window with no background will never have its
background filled by the windowing system, instead the window will
contain whatever pixels were already in the corresponding area of
the display.
The windowing system will normally fill a window with its background
when the window is obscured then exposed, and when you call
gdkWindowClear.