gtk-tree-view-path-at-pos (view x y)

view -- a gtk-tree-view widget
x -- an integer with the x position to be identified (relative to the bin window)
y -- an integer with the y position to be identified (relative to the bin window)

path -- a gtk-tree-path instance, or nil
column -- a gtk-tree-view-column object, or nil
cell-x -- an integer with the x coordinate relative to the cell
cell-y -- an integer with the y coordinate relative to the cell

Finds the path at the point (x, y), relative to the bin window coordinates. Please see the function gtk-tree-view-bin-window. That is, x and y are relative to an events coordinates. The x and y must coordinates come from an event on the tree view only where the event window from the function gdk-event-window is equal to the bin window from the function gtk-tree-view-bin-window. It is primarily for things like popup menus.

If path is non-nil, then it will be filled with the gtk-tree-path instance at that point. If column is non-nil, then it will be filled with the column at that point. The values cell-x and cell-y return the coordinates relative to the cell background, i.e. the background-area passed to the function gtk-cell-renderer-render. This function is only meaningful if the tree view is realized. Therefore this function will always return nil if the tree view is not realized or does not have a model.

For converting widget coordinates, e.g. the ones you get from the "query-tooltip" signal, please see the function gtk-tree-view-convert-widget-to-bin-window-coords.