Gets the GtkTextIter at the start of the line containing
the coordinate y. y is in buffer coordinates, convert from
window coordinates with gtk_text_view_window_to_buffer_coords().
If non-NULL, line_top will be filled with the coordinate of the top
edge of the line.
Gets the GtkTextIter at the start of the line containing the coordinate y. y is in buffer coordinates, convert from window coordinates with gtk_text_view_window_to_buffer_coords(). If non-NULL, line_top will be filled with the coordinate of the top edge of the line.