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[PATCH] TTY Support for ECMA-48 strike-through graphic rendition
From: |
Mike Hamrick |
Subject: |
[PATCH] TTY Support for ECMA-48 strike-through graphic rendition |
Date: |
Thu, 25 Jun 2020 14:44:11 -0700 |
User-agent: |
mu4e 1.0; emacs 25.3.1 |
Hello,
In 1984, the third edition of ECMA-48 "Control Functions for Coded
Character Sets" was published. In section 8.3.117 under "Select Graphic
Rendition" a new character attribute for "crossed-out" was added.
As Thomas Dickey notes, many escape sequences in ECMA-48 were in fact
created by a committee, and did not exist in hardware terminals of the
time, but were rather a framework for proposed terminal implementations.
Some 30 years on, many terminal programs such as xterm, gnome-terminal,
termite, st, konsole, and others have implemented the ECMA-48
strike-through escape sequences, however there wasn't a terminfo(5)
capability defined for the purpose until a few years ago.
Here is my patch which adds Emacs TTY support for strike-through
rendering, which I personally use in org-mode for done TODO items. In
order for this to work for you, your terminfo database entry needs to have the
"smxx" capability defined, which I believe more recent versions[0] of the
xterm entry have.
[0]: https://invisible-island.net/xterm/terminfo.html
* term.c: Support strike-through in capable terminals.
(no_color_bit): Replace unused NC_INVIS with NC_STRIKE_THROUGH.
(turn_on_face): Output via TS_enter_strike_through_mode if available.
(turn_off_face): Handle strike-through case.
(tty_capable_p, init_tty): Support strike-through.
* termchar.h (struct tty_display_info): Add field for strike-through.
* xfaces.c (tty_supports_face_attributes_p, realize_tty_face):
Handle strike-through case.
* dispextern.h: Add TTY_CAP_STRIKE_THROUGH definition.
(struct face): Add field tty_strike_through_p.
---
src/dispextern.h | 2 ++
src/term.c | 34 ++++++++++++++++++++--------------
src/termchar.h | 1 +
src/xfaces.c | 12 +++++++++++-
4 files changed, 34 insertions(+), 15 deletions(-)
diff --git a/src/dispextern.h b/src/dispextern.h
index e1d6eddc41..082a345441 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -1744,6 +1744,7 @@ #define FONT_TOO_HIGH(ft)
\
bool_bf tty_italic_p : 1;
bool_bf tty_underline_p : 1;
bool_bf tty_reverse_p : 1;
+ bool_bf tty_strike_through_p : 1;
/* True means that colors of this face may not be freed because they
have been copied bitwise from a base face (see
@@ -3290,6 +3291,7 @@ #define TTY_CAP_UNDERLINE 0x02
#define TTY_CAP_BOLD 0x04
#define TTY_CAP_DIM 0x08
#define TTY_CAP_ITALIC 0x10
+#define TTY_CAP_STRIKE_THROUGH 0x20
/***********************************************************************
diff --git a/src/term.c b/src/term.c
index 5cbb092ad1..bf5e339d2f 100644
--- a/src/term.c
+++ b/src/term.c
@@ -105,14 +105,14 @@ #define OUTPUT1_IF(tty, a) do { if (a) emacs_tputs
((tty), a, 1, cmputc); } whil
enum no_color_bit
{
- NC_STANDOUT = 1 << 0,
- NC_UNDERLINE = 1 << 1,
- NC_REVERSE = 1 << 2,
- NC_ITALIC = 1 << 3,
- NC_DIM = 1 << 4,
- NC_BOLD = 1 << 5,
- NC_INVIS = 1 << 6,
- NC_PROTECT = 1 << 7
+ NC_STANDOUT = 1 << 0,
+ NC_UNDERLINE = 1 << 1,
+ NC_REVERSE = 1 << 2,
+ NC_ITALIC = 1 << 3,
+ NC_DIM = 1 << 4,
+ NC_BOLD = 1 << 5,
+ NC_STRIKE_THROUGH = 1 << 6,
+ NC_PROTECT = 1 << 7
};
/* internal state */
@@ -1931,6 +1931,9 @@ turn_on_face (struct frame *f, int face_id)
if (face->tty_underline_p && MAY_USE_WITH_COLORS_P (tty, NC_UNDERLINE))
OUTPUT1_IF (tty, tty->TS_enter_underline_mode);
+ if (face->tty_strike_through_p && MAY_USE_WITH_COLORS_P (tty,
NC_STRIKE_THROUGH))
+ OUTPUT1_IF (tty, tty->TS_enter_strike_through_mode);
+
if (tty->TN_max_colors > 0)
{
const char *ts;
@@ -1971,7 +1974,8 @@ turn_off_face (struct frame *f, int face_id)
if (face->tty_bold_p
|| face->tty_italic_p
|| face->tty_reverse_p
- || face->tty_underline_p)
+ || face->tty_underline_p
+ || face->tty_strike_through_p)
{
OUTPUT1_IF (tty, tty->TS_exit_attribute_mode);
if (strcmp (tty->TS_exit_attribute_mode, tty->TS_end_standout_mode)
== 0)
@@ -2006,11 +2010,12 @@ #define TTY_CAPABLE_P_TRY(tty, cap, TS, NC_bit)
\
if ((caps & (cap)) && (!(TS) || !MAY_USE_WITH_COLORS_P(tty, NC_bit)))
\
return 0;
- TTY_CAPABLE_P_TRY (tty, TTY_CAP_INVERSE, tty->TS_standout_mode,
NC_REVERSE);
- 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_ITALIC, tty->TS_enter_italic_mode,
NC_ITALIC);
+ TTY_CAPABLE_P_TRY (tty, TTY_CAP_INVERSE, tty->TS_standout_mode,
NC_REVERSE);
+ 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_ITALIC, tty->TS_enter_italic_mode,
NC_ITALIC);
+ TTY_CAPABLE_P_TRY (tty, TTY_CAP_STRIKE_THROUGH,
tty->TS_enter_strike_through_mode, NC_STRIKE_THROUGH);
/* We can do it! */
return 1;
@@ -4124,6 +4129,7 @@ init_tty (const char *name, const char *terminal_type,
bool must_succeed)
tty->TS_enter_alt_charset_mode = tgetstr ("as", address);
tty->TS_exit_alt_charset_mode = tgetstr ("ae", address);
tty->TS_exit_attribute_mode = tgetstr ("me", address);
+ tty->TS_enter_strike_through_mode = tgetstr ("smxx", address);
MultiUp (tty) = tgetstr ("UP", address);
MultiDown (tty) = tgetstr ("DO", address);
diff --git a/src/termchar.h b/src/termchar.h
index c96b81913b..a8b3051767 100644
--- a/src/termchar.h
+++ b/src/termchar.h
@@ -136,6 +136,7 @@ #define EMACS_TERMCHAR_H
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. */
+ const char *TS_enter_strike_through_mode; /* "smxx" -- turn on
strike-through mode. */
/* "as"/"ae" -- start/end alternate character set. Not really
supported, yet. */
diff --git a/src/xfaces.c b/src/xfaces.c
index c4a4e1c94f..dc6ea5eacf 100644
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -5207,7 +5207,6 @@ tty_supports_face_attributes_p (struct frame *f,
|| !UNSPECIFIEDP (attrs[LFACE_HEIGHT_INDEX])
|| !UNSPECIFIEDP (attrs[LFACE_SWIDTH_INDEX])
|| !UNSPECIFIEDP (attrs[LFACE_OVERLINE_INDEX])
- || !UNSPECIFIEDP (attrs[LFACE_STRIKE_THROUGH_INDEX])
|| !UNSPECIFIEDP (attrs[LFACE_BOX_INDEX]))
return false;
@@ -5272,6 +5271,15 @@ tty_supports_face_attributes_p (struct frame *f,
test_caps |= TTY_CAP_INVERSE;
}
+ /* strike through */
+ val = attrs[LFACE_STRIKE_THROUGH_INDEX];
+ if (!UNSPECIFIEDP (val))
+ {
+ if (face_attr_equal_p (val, def_attrs[LFACE_STRIKE_THROUGH_INDEX]))
+ return false; /* same as default */
+ else
+ test_caps |= TTY_CAP_STRIKE_THROUGH;
+ }
/* Color testing. */
@@ -6234,6 +6242,8 @@ realize_tty_face (struct face_cache *cache,
face->tty_underline_p = true;
if (!NILP (attrs[LFACE_INVERSE_INDEX]))
face->tty_reverse_p = true;
+ if (!NILP (attrs[LFACE_STRIKE_THROUGH_INDEX]))
+ face->tty_strike_through_p = true;
/* Map color names to color indices. */
map_tty_color (f, face, LFACE_FOREGROUND_INDEX, &face_colors_defaulted);
--
2.24.0
- [PATCH] TTY Support for ECMA-48 strike-through graphic rendition,
Mike Hamrick <=