From 614e6c9d5e5b44c11f11f3432a8f44f1652cdda4 Mon Sep 17 00:00:00 2001
From: Pasi Kallinen <paxed@alt.org>
Date: Tue, 24 Oct 2023 18:34:15 +0300
Subject: [PATCH] MSDOS: implement inverse text attribute

---
 doc/fixes3-7-0.txt  |  1 +
 sys/msdos/video.c   | 19 +++++++++++--------
 sys/msdos/vidvesa.c | 12 ++++++++++++
 sys/msdos/vidvga.c  |  7 +++++++
 4 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/doc/fixes3-7-0.txt b/doc/fixes3-7-0.txt
index c04beeb23..e1eeb00f9 100644
--- a/doc/fixes3-7-0.txt
+++ b/doc/fixes3-7-0.txt
@@ -1856,6 +1856,7 @@ macOS: Xcode project was failing to build if the path to the NetHack source
 MS-DOS: add -DSTATUES_LOOK_LIKE_MONSTERS to Makefile1.cross so the VESA mode
 	can display statue glyphs
 MS-DOS: sample config file had same MENUCOLOR flaw as Windows (see below)
+MS-DOS: implement inverse text attribute
 Qt: quit if can't load tiles file instead of continuing and then segfaulting
 Qt: [later] tiles load failure at startup now continues using an ascii map
 Qt: use more columns for extended command selection dialog so that the number
diff --git a/sys/msdos/video.c b/sys/msdos/video.c
index 86b49c96c..c23445f87 100644
--- a/sys/msdos/video.c
+++ b/sys/msdos/video.c
@@ -128,6 +128,7 @@ int savevmode;               /* store the original video mode in here */
 int curcol, currow;          /* graphics mode current cursor locations */
 int g_attribute;             /* Current attribute to use */
 int monoflag;                /* 0 = not monochrome, else monochrome */
+int inversed;
 int attrib_text_normal;      /* text mode normal attribute */
 int attrib_gr_normal;        /* graphics mode normal attribute */
 int attrib_text_intense;     /* text mode intense attribute */
@@ -296,10 +297,12 @@ void
 term_end_attr(int attr)
 {
     switch (attr) {
+    case ATR_INVERSE:
+        inversed = 0;
+        /*FALLTHRU*/
     case ATR_ULINE:
     case ATR_BOLD:
     case ATR_BLINK:
-    case ATR_INVERSE:
     default:
         g_attribute = iflags.grmode ? attrib_gr_normal : attrib_text_normal;
     }
@@ -343,13 +346,8 @@ term_start_attr(int attr)
         }
         break;
     case ATR_INVERSE:
-        if (monoflag) {
-            g_attribute = ATTRIB_MONO_REVERSE;
-        } else {
-            g_attribute =
-                iflags.grmode ? attrib_gr_intense : attrib_text_intense;
-        }
-        break;
+        inversed = 1;
+        /*FALLTHRU*/
     default:
         g_attribute = iflags.grmode ? attrib_gr_normal : attrib_text_normal;
         break;
@@ -477,6 +475,8 @@ tty_startup(int *wid, int *hgt)
 #else
     monoflag = 0;
 #endif
+
+    inversed = 0;
 }
 
 void
@@ -600,6 +600,9 @@ xputc(int ch) /* write out character (and attribute) */
     }
 
     if (!iflags.grmode) {
+        if (inversed) {
+            attribute = (g_attribute % 8) << 4;
+        }
         txt_xputc(ch, attribute);
 #ifdef SCREEN_VGA
     } else if (iflags.usevga) {
diff --git a/sys/msdos/vidvesa.c b/sys/msdos/vidvesa.c
index 81f1bc167..a6afbc80f 100644
--- a/sys/msdos/vidvesa.c
+++ b/sys/msdos/vidvesa.c
@@ -24,6 +24,7 @@ extern int total_tiles_used, Tile_corr, Tile_unexplored;  /* from tile.c */
 struct VesaCharacter {
     uint32 colour, bgcolour;
     uint32 chr;
+    char inverse;
 };
 
 static unsigned long vesa_SetWindow(int window, unsigned long offset);
@@ -69,6 +70,7 @@ extern int clipx, clipxmax; /* current clipping column from wintty.c */
 extern int clipy, clipymax; /* current clipping row from wintty.c */
 extern int curcol, currow;  /* current column and row        */
 extern int g_attribute;
+extern int inversed;
 extern int attrib_text_normal;  /* text mode normal attribute */
 extern int attrib_gr_normal;    /* graphics mode normal attribute */
 extern int attrib_gr_intense;   /* graphics mode intense attribute */
@@ -1603,6 +1605,7 @@ vesa_WriteCharXY(uint32 chr, int pixx, int pixy, uint32 colour)
     }
     chr_cache_lastx = pixx;
     chr_cache[chr_cache_size].chr = chr;
+    chr_cache[chr_cache_size].inverse = inversed;
     chr_cache[chr_cache_size].colour = colour;
     chr_cache[chr_cache_size].bgcolour = BACKGROUND_VESA_COLOR;
     ++chr_cache_size;
@@ -1694,6 +1697,15 @@ vesa_WriteTextRow(int pixx, int pixy, struct VesaCharacter const *t_row,
                 fg[2] = (pix >> 16) & 0xFF;
                 fg[3] = (pix >> 24) & 0xFF;
             }
+
+            if (t_row[i].inverse) {
+                unsigned char tmpx[4];
+                tmpx[0] = bg[0]; bg[0] = fg[0]; fg[0] = tmpx[0];
+                tmpx[1] = bg[1]; bg[1] = fg[1]; fg[1] = tmpx[1];
+                tmpx[2] = bg[2]; bg[2] = fg[2]; fg[2] = tmpx[2];
+                tmpx[3] = bg[3]; bg[3] = fg[3]; fg[3] = tmpx[3];
+            }
+
             /* Third loop: draw eight pixels */
             for (px = 0; px < (int) vesa_char_width; px += 8) {
                 /* Fourth loop: draw one pixel */
diff --git a/sys/msdos/vidvga.c b/sys/msdos/vidvga.c
index aa287e83e..c5e887703 100644
--- a/sys/msdos/vidvga.c
+++ b/sys/msdos/vidvga.c
@@ -138,6 +138,7 @@ extern boolean clipping;    /* clipping on? from wintty.c */
 extern int savevmode;       /* store the original video mode */
 extern int curcol, currow;  /* current column and row        */
 extern int g_attribute;
+extern int inversed;
 extern int attrib_text_normal;  /* text mode normal attribute */
 extern int attrib_gr_normal;    /* graphics mode normal attribute */
 extern int attrib_text_intense; /* text mode intense attribute */
@@ -965,6 +966,12 @@ vga_WriteChar(uint32 chr, int col, int row, int colour)
     else
         bgcolor = BACKGROUND_VGA_COLOR;
 
+    if (inversed) {
+        int tmpc = actual_colour;
+        actual_colour = bgcolor;
+        bgcolor = tmpc;
+    }
+
     x = min(col, (CO - 1));         /* min() used protection from callers */
     pixy = min(row, (LI - 1)) * 16; /* assumes 8 x 16 char set */
     vplane = ~actual_colour & ~bgcolor & 0xF;