tty_update.c (part 3)

[Philippe Blain]

>From Philippe Blain, Bordeaux, France.
My old computer: P133 - 8,4 Go - 32 Mo Red Hat Linux 7.0

To maintainers of 'ncurses'.(and to Mr Dickey)
Subject: Corrections for ncurses-5.3-20021206+

Here are some problems I found :

----------------------------------------------------------------------------
File : ncurses/base/tty_update.c

In all hard-scroll functions, tputs is used with parameter 0 , meaning
a delay of 0 milliseconds.
The padding is not done by tputs on terminals which require it.

    tputs (scroll_forward, 0, _nc_outch);  --> e.g DEC vt132
    tputs (scroll_reverse, 0, _nc_outch);  --> e.g Arm Risc PC, vt100
    tputs (delete_line, 0, _nc_outch);     --> e.g wyse 120,150
    tputs (insert_line, 0, _nc_outch);     --> e.g wyse

Should be set to 1 (n if proportional) or use "putp(capability);".

----------------------------------------------------------------------------
File : ncurses/base/tty_update.c

Line 1656 :
I don't understand the test for saving cursor when the terminal has a
settable scrolling region.  Is it some rest of old code ?
The terminfo pages do not mention that the cursor must be at bottom
before setting a scrolling region, and I don't see relation with n==1 ?
All sufficient cases are considered in scroll_csr_forward/backward.


if (res == ERR && change_scroll_region) {
==> if ((((n == 1 && scroll_forward) || parm_index)
==>      && (SP->_cursrow == bot || SP->_cursrow == bot - 1))
==>     && save_cursor && restore_cursor) {
        cursor_saved = TRUE;
        TPUTS_TRACE ("save_cursor");
        tputs (save_cursor, 0, _nc_outch);
    }
    TPUTS_TRACE ("change_scroll_region");
    tputs (tparm (change_scroll_region, top, bot), 0, _nc_outch);
    if (cursor_saved) {
        TPUTS_TRACE ("restore_cursor");
        tputs (restore_cursor, 0, _nc_outch);
==>     cursor_saved = FALSE;  /* secure */
    }
    else {
        SP->_cursrow = SP->_curscol = -1;
    }

    res = scroll_csr_forward (n, top, bot, top, bot, blank);

    TPUTS_TRACE ("change_scroll_region");
    tputs (tparm (change_scroll_region, 0, maxy), 0, _nc_outch);
    SP->_cursrow = SP->_curscol = -1;
}

----------------------------------------------------------------------------
File : ncurses/base/tty_update.c
Line 1689 :
        ................
        if (bot == maxy && clr_eos) {
==>     GoTo(bot - n, 0);
        ClrToEOS(blank2);
        ................
Should be GoTo(bot - n + 1, 0); because in the following 'else{..}',
i varies from 0 to n - 1 inclusive starting from bottom.

----------------------------------------------------------------------------
File : ncurses/base/tty_update.c

The following new routine clears the screen between 2 lines inclusive.

static int _hard_clear_from_to (int y1, int y2, NCURSES_CH_T blank)
{
    TR (TRACE_UPDATE, ("_hard_clear_from_to() called"));

    if (clr_eol && can_clear_with (CHREF (blank))) {
        int i, j, row, col;

        row = SP->_cursrow;
        col = SP->_curscol;

        UpdateAttrs (AttrOf (blank));
        if (y2 >= screen_lines - 1 && clr_eos) {
            GoTo (0, y1);
            TPUTS_TRACE ("clr_eos");
            tputs (clr_eos, screen_lines - y1, _nc_outch);
        }
        else {
            for (i = y1; i <= y2 && i < screen_lines; i++) {
                GoTo (0, i);
                TPUTS_TRACE ("clr_eol");
                putp (clr_eol);
            }
        }
        GoTo (col, row);
        for (i = y1; i <= y2; i++)
            for (j = 0; j < screen_columns; j++)
                curscr->_line[i].text[j] = blank;
        returnCode (OK);
    }
    else returnCode (ERR);
}

Can be used in _nc_scrolln()
Line 1688 and 1734 :
................
if (res != ERR &&
    (non_dest_scroll_region || (memory_below && bot == maxy))) {
        NCURSES_CH_T blank2 = NewChar (BLANK_TEXT);
==>     _hard_clear_from_to (bot - n + 1, bot, blank2);
}
................
if (res != ERR &&
    (non_dest_scroll_region || (memory_above && top == 0))) {
        NCURSES_CH_T blank2 = NewChar (BLANK_TEXT);
==>     _hard_clear_from_to (top, top - n - 1, blank2);
}
................

----------------------------------------------------------------------------
- Philippe