From: Gurusamy Sarathy To: Michael Schroeder cc: Gurusamy Sarathy , Juergen Weigert Date: Sat, 16 Feb 2002 04:56:51 -0800 Message-Id: <200202161256.g1GCupL22222@smtp3.ActiveState.com> Subject: Re: alt-screen support OK, I've attached a patch against 3.9.11 for altscreen support. It appears to work nicely in my (fairly limited) tests. One issue I noticed is that the termcapinfo command in .screenrc doesn't seem to add the te/ti sequences properly. Rather, dumptermcap does print out those sequences, but it never switches to the alternate screen. If I add those as smcup/rmcup entries into my terminfo database, everything works. I suspect something is wrong with how the termcapinfo command is processed. The sample screenrc has a XXX comment about this. I'm going to leave someone more knowledgeable about the internals to look into this. Thanks, Sarathy gsar@ActiveState.com -----------------------------------8<----------------------------------- diff -ruN screen-3.9.11/ansi.c screen-3.9.11-plus/ansi.c --- screen-3.9.11/ansi.c Tue Jan 8 07:43:05 2002 +++ screen-3.9.11-plus/ansi.c Sat Feb 16 04:34:07 2002 @@ -58,6 +58,7 @@ static struct win *curr; /* window we are working on */ static int rows, cols; /* window size of the curr window */ +int use_altscreen = 0; /* enable alternate screen support? */ int visual_bell = 0; int use_hardstatus = 1; /* display status line in hs */ char *printcmd = 0; @@ -1334,6 +1335,13 @@ /* case 40: 132 col enable */ /* case 42: NRCM: 7bit NRC character mode */ /* case 44: margin bell enable */ + case 47: /* xterm-like alternate screen */ + if (use_altscreen) + { + i ? EnterAltScreen(curr) : LeaveAltScreen(curr); + LRefreshAll(&curr->w_layer, 0); + } + break; /* case 66: NKM: Numeric keypad appl mode */ /* case 68: KBUM: Keyboard usage mode (data process) */ case 1000: /* VT200 mouse tracking */ diff -ruN screen-3.9.11/comm.c screen-3.9.11-plus/comm.c --- screen-3.9.11/comm.c Wed Feb 6 02:19:00 2002 +++ screen-3.9.11-plus/comm.c Sat Feb 16 04:34:07 2002 @@ -55,6 +55,7 @@ { "addacl", ARGS_1234 }, #endif { "allpartial", NEED_DISPLAY|ARGS_1 }, + { "altscreen", ARGS_1 }, { "at", NEED_DISPLAY|ARGS_2|ARGS_ORMORE }, #ifdef COLOR { "attrcolor", ARGS_12 }, diff -ruN screen-3.9.11/doc/screen.1 screen-3.9.11-plus/doc/screen.1 --- screen-3.9.11/doc/screen.1 Wed Feb 6 03:40:03 2002 +++ screen-3.9.11-plus/doc/screen.1 Sat Feb 16 04:34:07 2002 @@ -748,6 +748,13 @@ default redraw behavior of newly created windows. .sp .ne 3 +.BR "altscreen on" | off +.PP +If set to on, "alternate screen" support is enabled in virtual terminals, +just like in xterm. Enabling it makes the \eE[?47h and \eE[?47l escapes +work inside a screen session. Initial setting is `off'. +.sp +.ne 3 .BR "at " "[\fIidentifier\fP][" "#\fP|\fP*\fP|\fP%\fP] " .IR "command " [ args " ... ]" .PP @@ -3632,6 +3639,9 @@ the session is reattached on a different terminal, as the value of $TERMCAP cannot be modified by parent processes. .PP +The "alternate screen" capability is not enabled by default. +Set the \fBaltscreen\fP .screenrc command to enable it. +.PP The following is a list of control sequences recognized by .IR screen . \*Q(V)\*U and \*Q(A)\*U indicate VT100-specific and ANSI- or @@ -3958,6 +3968,9 @@ .TP 27 \h'\w'ESC [ Ps = 'u'\fB?25\fP (V) Visible Cursor +.TP 27 +\h'\w'ESC [ Ps = 'u'\fB?47\fP +Alternate Screen .TP 27 \h'\w'ESC [ Ps = 'u'\fB?1000\fP (V) VT200 mouse tracking diff -ruN screen-3.9.11/doc/screen.texinfo screen-3.9.11-plus/doc/screen.texinfo --- screen-3.9.11/doc/screen.texinfo Wed Feb 13 02:37:42 2002 +++ screen-3.9.11-plus/doc/screen.texinfo Sat Feb 16 04:35:47 2002 @@ -821,6 +821,8 @@ Synonym to @code{acladd}. @xref{Multiuser Session}. @item allpartial @var{state} Set all windows to partial refresh. @xref{Redisplay}. +@item altscreen @var{state} +Enables support for the "alternate screen" terminal capability. @xref{Redisplay}. @item at [@var{ident}][@kbd{#}@var{|}@kbd{*}@var{|}@kbd{%}] @var{command} [@var{args}] Execute a command at other displays or windows. @xref{At}. @item attrcolor @var{attrib} [@var{attribute/color-modifier}] @@ -2334,6 +2336,7 @@ ?7 (V) @samp{Wrap} Mode ?9 X10 mouse tracking ?25 (V) Visible Cursor + ?47 Alternate Screen ?1000 (V) VT200 mouse tracking ESC [ 5 i (A) Start relay to printer (ANSI Media Copy) ESC [ 4 i (A) Stop relay to printer (ANSI Media Copy) @@ -2575,6 +2578,13 @@ default redraw behavior of newly created windows. @end deffn +@deffn Command altscreen state +(none)@* +If set to on, "alternate screen" support is enabled in virtual terminals, +just like in xterm. Enabling it makes the \E[?47h and \E[?47l escapes +work inside a screen session. Initial setting is @samp{off}. +@end deffn + @deffn Command partial state (none)@* Defines whether the display should be refreshed (as with @@ -3717,6 +3727,9 @@ cannot be modified by parent processes. You can force @code{screen} to include all capabilities in @code{$TERMCAP} with the @samp{-a} command-line option (@pxref{Invoking Screen}). + +The "alternate screen" capability is not enabled by default. +Set the @code{altscreen} @file{.screenrc} command to enable it. @node Dump Termcap, Termcap Syntax, Window Termcap, Termcap @section Write out the window's termcap entry diff -ruN screen-3.9.11/etc/screenrc screen-3.9.11-plus/etc/screenrc --- screen-3.9.11/etc/screenrc Thu Feb 14 05:36:33 2002 +++ screen-3.9.11-plus/etc/screenrc Sat Feb 16 04:34:07 2002 @@ -35,6 +35,15 @@ # don't kill window after the process died # zombie "^[" +# enable support for the "alternate screen" capability in all windows +#altscreen on + +# enabling altscreen is useless if you don't have the corresponding +# escapes in your screen termcap/terminfo entries; you can set them +# right here instead of mucking with termcap/terminfo. +# XXX this doesn't seem to work! +#termcapinfo screen* '' 'ti=\E7\E[?47h:te=\E[2J\E[?47l\E8' + ################ # # xterm tweaks diff -ruN screen-3.9.11/extern.h screen-3.9.11-plus/extern.h --- screen-3.9.11/extern.h Tue Feb 5 10:12:41 2002 +++ screen-3.9.11-plus/extern.h Sat Feb 16 04:34:07 2002 @@ -303,6 +303,8 @@ extern void ResizeLayersToCanvases __P((void)); extern void ResizeLayer __P((struct layer *, int, int, struct display *)); extern int MayResizeLayer __P((struct layer *)); +extern void EnterAltScreen __P((struct win *)); +extern void LeaveAltScreen __P((struct win *)); /* sched.c */ extern void evenq __P((struct event *)); diff -ruN screen-3.9.11/process.c screen-3.9.11-plus/process.c --- screen-3.9.11/process.c Mon Feb 11 04:30:08 2002 +++ screen-3.9.11-plus/process.c Sat Feb 16 04:34:07 2002 @@ -60,7 +60,7 @@ extern char *VisualBellString; extern int VBellWait, MsgWait, MsgMinWait, SilenceWait; extern char SockPath[], *SockName; -extern int TtyMode, auto_detach; +extern int TtyMode, auto_detach, use_altscreen; extern int iflag; extern int use_hardstatus, visual_bell; #ifdef COLOR @@ -2842,6 +2842,9 @@ TtyMode = n; if (msgok) Msg(0, "Ttymode set to %03o", TtyMode); + break; + case RC_ALTSCREEN: + (void)ParseOnOff(act, &use_altscreen); break; case RC_AUTODETACH: (void)ParseOnOff(act, &auto_detach); diff -ruN screen-3.9.11/resize.c screen-3.9.11-plus/resize.c --- screen-3.9.11/resize.c Mon Jan 28 02:38:21 2002 +++ screen-3.9.11-plus/resize.c Sat Feb 16 04:34:07 2002 @@ -73,6 +73,65 @@ #endif }; +void +EnterAltScreen(p) +struct win *p; +{ + struct mline *mlines; + + mlines = (struct mline *)calloc(p->w_height, sizeof(struct mline)); + if (mlines) + { + int ht = p->w_height; + int wi = p->w_width; + while (ht) + { + --ht; + if (AllocMline(&mlines[ht], wi+1)) + { + while (++ht < p->w_height) + FreeMline(&mlines[ht]); + free((char*)mlines); + return; + } + MakeBlankLine(mlines[ht].image, wi+1); + } + if (p->w_altscreen) /* garbled screen? */ + { + int ht = p->w_altscreen_lines; + while (ht) + FreeMline(&p->w_altscreen[--ht]); + free((char*)p->w_altscreen); + } + p->w_altscreen = p->w_mlines; + p->w_altscreen_lines = p->w_height; + p->w_alt_histheight = p->w_histheight; + p->w_mlines = mlines; + p->w_histheight = 0; /* altscreen has no history */ + } +} + +void +LeaveAltScreen(p) +struct win *p; +{ + if (p->w_altscreen) + { + if (p->w_mlines) + { + int ht = p->w_height; + while (ht) + FreeMline(&p->w_mlines[--ht]); + free((char*)p->w_mlines); + } + p->w_mlines = p->w_altscreen; + p->w_histheight = p->w_alt_histheight; + p->w_altscreen = NULL; + p->w_altscreen_lines = 0; + p->w_alt_histheight = 0; + } +} + /* * ChangeFlag: 0: try to modify no window * 1: modify fore (and try to modify no other) + redisplay diff -ruN screen-3.9.11/window.h screen-3.9.11-plus/window.h --- screen-3.9.11/window.h Tue Jan 8 07:42:51 2002 +++ screen-3.9.11-plus/window.h Sat Feb 16 04:34:07 2002 @@ -164,6 +164,9 @@ enum state_t w_state; /* parser state */ enum string_t w_StringType; struct mline *w_mlines; + struct mline *w_altscreen; /* backup lines for altscreen */ + int w_altscreen_lines; /* how many backup lines for altscreen */ + int w_alt_histheight; /* histheight before switch to altscreen */ struct mchar w_rend; /* current rendition */ #ifdef FONT char w_FontL; /* character font GL */ End of Patch.