option NoAltScreen disables the alternate screen (~mintty#652)

docs/mintty.1

@@ -849,8 +849,8 @@ bolding is simulated by rendering the text twice with a one-pixel offset.
 .TP
 \fBShow bold as colour\fP (BoldAsColour=yes)
 By default, text with the ANSI bold attribute set is displayed with a
-different colour, usually with increased brightness.  This can be disabled
-here.
+different colour, usually with increased brightness (mapping ANSI colours 
+0..7 to their bright variants 8..15). This can be disabled here.
 
 Note that when \fBBoldAsFont\fP is enabled, only bold text in one of the eight
 ANSI colours has its colour changed, i.e. bold text without an explicitly
@@ -1232,6 +1232,10 @@ is the default.
 The answerback string is sent in response to the \fB^E\fP (ENQ) character.
 By default, this is empty.
 
+.TP
+\fBAlternate screen\fP (NoAltScreen=false)
+With this setting, the alternate screen can be disabled.
+
 .TP
 \fBApply old wraparound behaviour\fP (OldWrapModes=false)
 Setting this compatibility option disables some tweaks and fixes of 

src/config.c

@@ -126,6 +126,7 @@ const config default_cfg = {
   .daemonize_always = false,
   // "Hidden"
   .bidi = 2,
+  .disable_alternate_screen = false,
   .app_id = W(""),
   .app_name = W(""),
   .app_launch_cmd = W(""),
@@ -297,6 +298,7 @@ options[] = {
 
   // "Hidden"
   {"Bidi", OPT_INT, offcfg(bidi)},
+  {"NoAltScreen", OPT_BOOL, offcfg(disable_alternate_screen)},
   {"AppID", OPT_WSTRING, offcfg(app_id)},
   {"AppName", OPT_WSTRING, offcfg(app_name)},
   {"AppLaunchCmd", OPT_WSTRING, offcfg(app_launch_cmd)},

src/config.h

@@ -134,6 +134,7 @@ typedef struct {
   bool daemonize_always;
   // "Hidden"
   int bidi;
+  bool disable_alternate_screen;
   wstring app_id;
   wstring app_name;
   wstring app_launch_cmd;

src/termout.c

@@ -633,10 +633,6 @@ set_modes(bool state)
           term.cursor_on = state;
         when 40: /* Allow/disallow DECCOLM (xterm c132 resource) */
           term.deccolm_allowed = state;
-        when 47: /* alternate screen */
-          term.selected = false;
-          term_switch_screen(state, false);
-          term.disptop = 0;
         when 67: /* DECBKM: backarrow key mode */
           term.backspace_sends_bs = state;
         when 80: /* DECSDM: SIXEL display mode */
@@ -664,23 +660,35 @@ set_modes(bool state)
           term.bell_taskbar = state;
         when 1043:
           term.bell_popup = state;
+        when 47: /* alternate screen */
+          if (!cfg.disable_alternate_screen) {
+            term.selected = false;
+            term_switch_screen(state, false);
+            term.disptop = 0;
+          }
         when 1047:       /* alternate screen */
-          term.selected = false;
-          term_switch_screen(state, true);
-          term.disptop = 0;
+          if (!cfg.disable_alternate_screen) {
+            term.selected = false;
+            term_switch_screen(state, true);
+            term.disptop = 0;
+          }
         when 1048:       /* save/restore cursor */
-          if (state)
-            save_cursor();
-          else
-            restore_cursor();
+          if (!cfg.disable_alternate_screen) {
+            if (state)
+              save_cursor();
+            else
+              restore_cursor();
+          }
         when 1049:       /* cursor & alternate screen */
-          if (state)
-            save_cursor();
-          term.selected = false;
-          term_switch_screen(state, true);
-          if (!state)
-            restore_cursor();
-          term.disptop = 0;
+          if (!cfg.disable_alternate_screen) {
+            if (state)
+              save_cursor();
+            term.selected = false;
+            term_switch_screen(state, true);
+            if (!state)
+              restore_cursor();
+            term.disptop = 0;
+          }
         when 1061:       /* VT220 keyboard emulation */
           term.vt220_keys = state;
         when 2004:       /* xterm bracketed paste mode */

wiki/Changelog.md

@@ -4,6 +4,7 @@ Font rendering and display handling
   * Fixed cleanup of environment variables after user command (#654).
   * Fixed bidi display while showing other screen with Bidi=1 (#592, ~#392, ~#605).
   * Avoid being pushed behind other windows on Ctrl+TAB (#652).
+  * Option NoAltScreen disables the alternate screen (~#652).
 
 ### 2.7.6 (14 Apr 2017) ###