5 files changed, 57 insertions, 45 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 563faaae68b..fb8b2a7b956 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,23 @@
+2012-06-09  Chong Yidong  <cyd@gnu.org>
+
+        * term.c: Support italics in capable terminals (Bug#9652).
+        (no_color_bit): Replace unused NC_BLINK with NC_ITALIC.
+        (turn_on_face): Output using TS_enter_italic_mode if available.
+        Don't handle unused blinking and alt-charset cases.
+        (turn_off_face): Handle italic case; discard unused tty_blinking_p
+        and tty_alt_charset_p cases.
+        (tty_capable_p, init_tty): Support italics.
+
+        * termchar.h (struct tty_display_info): Add field for italics.
+        Remove unused blink field.
+
+        * xfaces.c (tty_supports_face_attributes_p, realize_tty_face):
+        Handle slant.
+
+        * dispextern.h: Replace unused TTY_CAP_BLINK with TTY_CAP_ITALIC.
+        (struct face): Remove unused fields tty_dim_p, tty_blinking_p, and
+        tty_alt_charset_p.  Add tty_italic_p.
+
 2012-06-09  Michael Albinus  <michael.albinus@gmx.de>
 
         * dbusbind.c (XD_BASIC_DBUS_TYPE): Use dbus_type_is_valid and
diff --git a/src/dispextern.h b/src/dispextern.h
index 979ade70bfc..b877bf9965a 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -1609,15 +1609,12 @@ struct face
   unsigned strike_through_color_defaulted_p : 1;
   unsigned box_color_defaulted_p : 1;
 
-  /* TTY appearances.  Blinking is not yet implemented.  Colors are
-     found in `lface' with empty color string meaning the default
-     color of the TTY.  */
+  /* TTY appearances.  Colors are found in `lface' with empty color
+     string meaning the default color of the TTY.  */
   unsigned tty_bold_p : 1;
-  unsigned tty_dim_p : 1;
+  unsigned tty_italic_p : 1;
   unsigned tty_underline_p : 1;
-  unsigned tty_alt_charset_p : 1;
   unsigned tty_reverse_p : 1;
-  unsigned tty_blinking_p : 1;
 
   /* 1 means that colors of this face may not be freed because they
      have been copied bitwise from a base face (see
@@ -2979,8 +2976,7 @@ enum tool_bar_item_image
 #define TTY_CAP_UNDERLINE       0x02
 #define TTY_CAP_BOLD            0x04
 #define TTY_CAP_DIM             0x08
-#define TTY_CAP_BLINK           0x10
-#define TTY_CAP_ALT_CHARSET     0x20
+#define TTY_CAP_ITALIC          0x10
 
 
 /***********************************************************************
diff --git a/src/term.c b/src/term.c
index 3d7a677374c..8ce2efc0929 100644
--- a/src/term.c
+++ b/src/term.c
@@ -122,12 +122,11 @@ enum no_color_bit
   NC_STANDOUT    = 1 << 0,
   NC_UNDERLINE   = 1 << 1,
   NC_REVERSE     = 1 << 2,
-  NC_BLINK       = 1 << 3,
+  NC_ITALIC      = 1 << 3,
   NC_DIM         = 1 << 4,
   NC_BOLD        = 1 << 5,
   NC_INVIS       = 1 << 6,
-  NC_PROTECT     = 1 << 7,
-  NC_ALT_CHARSET = 1 << 8
+  NC_PROTECT     = 1 << 7
 };
 
 /* internal state */
@@ -2022,17 +2021,16 @@ turn_on_face (struct frame *f, int face_id)
   if (face->tty_bold_p && MAY_USE_WITH_COLORS_P (tty, NC_BOLD))
     OUTPUT1_IF (tty, tty->TS_enter_bold_mode);
 
-  if (face->tty_dim_p && MAY_USE_WITH_COLORS_P (tty, NC_DIM))
-    OUTPUT1_IF (tty, tty->TS_enter_dim_mode);
-
-  /* Alternate charset and blinking not yet used.  */
-  if (face->tty_alt_charset_p
-      && MAY_USE_WITH_COLORS_P (tty, NC_ALT_CHARSET))
-    OUTPUT1_IF (tty, tty->TS_enter_alt_charset_mode);
-
-  if (face->tty_blinking_p
-      && MAY_USE_WITH_COLORS_P (tty, NC_BLINK))
-    OUTPUT1_IF (tty, tty->TS_enter_blink_mode);
+  if (face->tty_italic_p && MAY_USE_WITH_COLORS_P (tty, NC_ITALIC))
+    {
+      if (tty->TS_enter_italic_mode)
+        OUTPUT1 (tty, tty->TS_enter_italic_mode);
+      else
+        /* Italics mode is unavailable on many terminals.  In that
+           case, map slant to dimmed text; we want italic text to
+           appear different and dimming is not otherwise used.  */
+        OUTPUT1 (tty, tty->TS_enter_dim_mode);
+    }
 
   if (face->tty_underline_p && MAY_USE_WITH_COLORS_P (tty, NC_UNDERLINE))
     OUTPUT1_IF (tty, tty->TS_enter_underline_mode);
@@ -2077,27 +2075,19 @@ turn_off_face (struct frame *f, int face_id)
          half-bright, reverse-video, standout, underline.  It may or
          may not turn off alt-char-mode.  */
       if (face->tty_bold_p
-          || face->tty_dim_p
+          || face->tty_italic_p
           || face->tty_reverse_p
-          || face->tty_alt_charset_p
-          || face->tty_blinking_p
           || face->tty_underline_p)
         {
           OUTPUT1_IF (tty, tty->TS_exit_attribute_mode);
           if (strcmp (tty->TS_exit_attribute_mode, tty->TS_end_standout_mode) == 0)
             tty->standout_mode = 0;
         }
-
-      if (face->tty_alt_charset_p)
-        OUTPUT_IF (tty, tty->TS_exit_alt_charset_mode);
     }
   else
     {
       /* If we don't have "me" we can only have those appearances
          that have exit sequences defined.  */
-      if (face->tty_alt_charset_p)
-        OUTPUT_IF (tty, tty->TS_exit_alt_charset_mode);
-
       if (face->tty_underline_p)
         OUTPUT_IF (tty, tty->TS_exit_underline_mode);
     }
@@ -2128,8 +2118,7 @@ tty_capable_p (struct tty_display_info *tty, unsigned int caps,
   TTY_CAPABLE_P_TRY (tty, TTY_CAP_UNDERLINE,    tty->TS_enter_underline_mode,   NC_UNDERLINE);
   TTY_CAPABLE_P_TRY (tty, TTY_CAP_BOLD,         tty->TS_enter_bold_mode,        NC_BOLD);
   TTY_CAPABLE_P_TRY (tty, TTY_CAP_DIM,          tty->TS_enter_dim_mode,         NC_DIM);
-  TTY_CAPABLE_P_TRY (tty, TTY_CAP_BLINK,        tty->TS_enter_blink_mode,       NC_BLINK);
-  TTY_CAPABLE_P_TRY (tty, TTY_CAP_ALT_CHARSET,  tty->TS_enter_alt_charset_mode, NC_ALT_CHARSET);
+  TTY_CAPABLE_P_TRY (tty, TTY_CAP_ITALIC,       tty->TS_enter_italic_mode,      NC_ITALIC);
 
   /* We can do it!  */
   return 1;
@@ -3222,8 +3211,8 @@ use the Bourne shell command `TERM=... export TERM' (C-shell:\n\
   tty->TS_enter_underline_mode = tgetstr ("us", address);
   tty->TS_exit_underline_mode = tgetstr ("ue", address);
   tty->TS_enter_bold_mode = tgetstr ("md", address);
+  tty->TS_enter_italic_mode = tgetstr ("ZH", address);
   tty->TS_enter_dim_mode = tgetstr ("mh", address);
-  tty->TS_enter_blink_mode = tgetstr ("mb", address);
   tty->TS_enter_reverse_mode = tgetstr ("mr", address);
   tty->TS_enter_alt_charset_mode = tgetstr ("as", address);
   tty->TS_exit_alt_charset_mode = tgetstr ("ae", address);
diff --git a/src/termchar.h b/src/termchar.h
index d50ee805e03..102fe45350e 100644
--- a/src/termchar.h
+++ b/src/termchar.h
@@ -124,8 +124,8 @@ struct tty_display_info
                                    each as vpos and hpos) */
 
   const char *TS_enter_bold_mode; /* "md" -- turn on bold (extra bright mode).  */
+  const char *TS_enter_italic_mode; /* "ZH" -- turn on italics mode.  */
   const char *TS_enter_dim_mode; /* "mh" -- turn on half-bright mode.  */
-  const char *TS_enter_blink_mode; /* "mb" -- enter blinking mode.  */
   const char *TS_enter_reverse_mode; /* "mr" -- enter reverse video mode.  */
   const char *TS_exit_underline_mode; /* "us" -- start underlining.  */
   const char *TS_enter_underline_mode; /* "ue" -- end underlining.  */
diff --git a/src/xfaces.c b/src/xfaces.c
index 10d1c93fef8..772d2646291 100644
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -4884,14 +4884,13 @@ static int
 tty_supports_face_attributes_p (struct frame *f, Lisp_Object *attrs,
                                 struct face *def_face)
 {
-  int weight;
+  int weight, slant;
   Lisp_Object val, fg, bg;
   XColor fg_tty_color, fg_std_color;
   XColor bg_tty_color, bg_std_color;
   unsigned test_caps = 0;
   Lisp_Object *def_attrs = def_face->lface;
 
-
   /* First check some easy-to-check stuff; ttys support none of the
      following attributes, so we can just return false if any are requested
      (even if `nominal' values are specified, we should still return false,
@@ -4907,11 +4906,9 @@ tty_supports_face_attributes_p (struct frame *f, Lisp_Object *attrs,
       || !UNSPECIFIEDP (attrs[LFACE_SWIDTH_INDEX])
       || !UNSPECIFIEDP (attrs[LFACE_OVERLINE_INDEX])
       || !UNSPECIFIEDP (attrs[LFACE_STRIKE_THROUGH_INDEX])
-      || !UNSPECIFIEDP (attrs[LFACE_BOX_INDEX])
-      || !UNSPECIFIEDP (attrs[LFACE_SLANT_INDEX]))
+      || !UNSPECIFIEDP (attrs[LFACE_BOX_INDEX]))
     return 0;
 
-
   /* Test for terminal `capabilities' (non-color character attributes).  */
 
   /* font weight (bold/dim) */
@@ -4937,6 +4934,18 @@ tty_supports_face_attributes_p (struct frame *f, Lisp_Object *attrs,
         return 0;               /* same as default */
     }
 
+  /* font slant */
+  val = attrs[LFACE_SLANT_INDEX];
+  if (!UNSPECIFIEDP (val)
+      && (slant = FONT_SLANT_NAME_NUMERIC (val), slant >= 0))
+    {
+      int def_slant = FONT_SLANT_NAME_NUMERIC (def_attrs[LFACE_SLANT_INDEX]);
+      if (slant == 100 || slant == def_slant)
+        return 0; /* same as default */
+      else
+        test_caps |= TTY_CAP_ITALIC;
+    }
+
   /* underlining */
   val = attrs[LFACE_UNDERLINE_INDEX];
   if (!UNSPECIFIEDP (val))
@@ -5857,15 +5866,13 @@ realize_tty_face (struct face_cache *cache, Lisp_Object *attrs)
   face->font_name = FRAME_MSDOS_P (cache->f) ? "ms-dos" : "tty";
 #endif
 
-  /* Map face attributes to TTY appearances.  We map slant to
-     dimmed text because we want italic text to appear differently
-     and because dimmed text is probably used infrequently.  */
+  /* Map face attributes to TTY appearances.  */
   weight = FONT_WEIGHT_NAME_NUMERIC (attrs[LFACE_WEIGHT_INDEX]);
   slant = FONT_SLANT_NAME_NUMERIC (attrs[LFACE_SLANT_INDEX]);
   if (weight > 100)
     face->tty_bold_p = 1;
-  if (weight < 100 || slant != 100)
-    face->tty_dim_p = 1;
+  if (slant != 100)
+    face->tty_italic_p = 1;
   if (!NILP (attrs[LFACE_UNDERLINE_INDEX]))
     face->tty_underline_p = 1;
   if (!NILP (attrs[LFACE_INVERSE_INDEX]))