diff options
| -rw-r--r-- | lib/tv/src/tv_pg_gridfcns.erl | 32 |
1 files changed, 25 insertions, 7 deletions
diff --git a/lib/tv/src/tv_pg_gridfcns.erl b/lib/tv/src/tv_pg_gridfcns.erl index ab88e2864f..3d23c8a69f 100644 --- a/lib/tv/src/tv_pg_gridfcns.erl +++ b/lib/tv/src/tv_pg_gridfcns.erl @@ -205,8 +205,8 @@ resize_grid(NewWidth, NewHeight, ProcVars) -> check_nof_cols(ColsShown, (NofColsShown - NofCols), ColFrameIds, ColIds, RowIds, NofRows, RowHeight, FgColor, BgColor ), - clear_fields(lists:nthtail(NofColsShown, NewColIds), - lists:nthtail(NofRowsShown, NewRowIds)), + clear_fields(safe_nthtail(NofColsShown, NewColIds), + safe_nthtail(NofRowsShown, NewRowIds)), RowsToUpdate = lists:sublist(NewRowIds, NofRowsShown), @@ -279,7 +279,7 @@ resize_grid_column(RealCol, VirtualCol, Xdiff, ProcVars) -> % Update the ColWidths list. TempColWidths = lists:sublist(ColWidths, VirtualCol - 1) ++ - [NewWidthOfCol | lists:nthtail(VirtualCol, ColWidths)], + [NewWidthOfCol | safe_nthtail(VirtualCol, ColWidths)], % Check the other columns, whether a new column has to be created. ColsShown = compute_cols_shown(FirstColShown, TempColWidths, GridWidth, @@ -455,8 +455,8 @@ scroll_grid_horizontally(NewFirstColShown, ProcVars) -> refresh_visible_rows(RowsToUpdate, NewFirstColShown, NofColsShown, RowDataList, ListAsStr), % Clear fields currently not visible. - clear_fields(lists:nthtail(NofColsShown, NewColIds), - lists:nthtail(NofRowsShown, NewRowIds)), + clear_fields(safe_nthtail(NofColsShown, NewColIds), + safe_nthtail(NofRowsShown, NewRowIds)), NewGridP = GridP#grid_params{nof_cols = NewNofCols, @@ -1565,7 +1565,7 @@ update_col_widths(ColsShown, ColWidths, FirstColShown, DefaultColWidth) -> if NecessaryNofVirtualCols > NofVirtualCols -> TailNo = NofVirtualCols - FirstColShown + 1, % Always >= 0 !!! - NewColWidths ++ lists:nthtail(TailNo, ColsShown); + NewColWidths ++ safe_nthtail(TailNo, ColsShown); true -> NewColWidths end. @@ -1653,7 +1653,7 @@ compute_cols_shown(FirstColShown, ColWidths, GridWidth, _NofCols, DefaultColWidt ColWidthsLength < FirstColShown -> []; true -> - lists:nthtail(FirstColShown - 1, ColWidths) + safe_nthtail(FirstColShown - 1, ColWidths) end, compute_cols_shown(UsedColWidths, GridWidth, DefaultColWidth). @@ -1894,3 +1894,21 @@ extract_ids_for_one_row(N, [ColIds | Tail]) -> %%%--------------------------------------------------------------------- %%% END of functions used to create the grid. %%%--------------------------------------------------------------------- + + +%%====================================================================== +%% Function: +%% +%% Return Value: +%% +%% Description: +%% +%% Parameters: +%%====================================================================== + + +safe_nthtail(_, []) -> []; +safe_nthtail(1, [_|T]) -> T; +safe_nthtail(N, [_|T]) when N > 1 -> + safe_nthtail(N - 1, T); +safe_nthtail(0, L) when is_list(L) -> L. |