gdk:window-coords-from-parent (window xparent yparent)

window -- a gdk:window child window
xparent -- a number coerced to a double float with the x coordinate in parent's coordinate system
yparent -- a number coerced to a double float with the y coordinate in parent's coordinate system

x -- a double float with the x coordinate in child's coordinate system
y -- a double float with the y coordinate in child's coordinate system

Transforms window coordinates from a parent window to a child window, where the parent window is the normal parent as returned by the gdk:window-parent function for normal windows, and the window's embedder as returned by the gdk:offscreen-window-embedder function for offscreen windows.

For normal windows, calling this function is equivalent to subtracting the return values of the gdk:window-position function from the parent coordinates. For offscreen windows however, which can be arbitrarily transformed, this function calls the "from-embedder" signal to translate the coordinates.

You should always use this function when writing generic code that walks down a window hierarchy.

See also the gdk:window-coords-to-parent function.