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.