computeBounds
Computes the bounds for @widget in the coordinate space of @target.
The bounds of widget are (the bounding box of) the region that it is expected to draw in. See the coordinates.html overview to learn more.
If the operation is successful, true is returned. If @widget has no bounds or the bounds cannot be expressed in @target's coordinate space (for example if both widgets are in different windows), false is returned and @bounds is set to the zero rectangle.
It is valid for @widget and @target to be the same widget.
Return
true if the bounds could be computed
Parameters
target
the GtkWidget
outBounds
the rectangle taking the bounds