[PATCH v2] Support 24-bit terminal colors.

[PATCH v2] Support 24-bit terminal colors.

[Rami Ylimäki]

From: Rami Ylimäki <rjy@iki.fi>

I have tested these changes on gnome-terminal/Ubuntu and iTerm2/OSX.

Rami Ylimäki (3):
  Remove unused terminal color pair count.
  Support 24-bit terminal colors.
  Let user turn 24-bit terminal colors on.

 lisp/term/tty-colors.el | 19 +++++++++++++++++--
 lisp/term/xterm.el      |  8 ++++++++
 src/term.c              | 20 ++++++++++++++------
 src/termchar.h          |  4 ----
 src/tparam.h            |  4 ++++
 5 files changed, 43 insertions(+), 12 deletions(-)

-- 
2.7.4

[PATCH 1/3] Remove unused terminal color pair count.

[Rami Ylimäki]

From: Rami Ylimäki <rjy@iki.fi>

The TN_max_pairs field is unused and would be inconvenient with direct
color modes.

* src/termchar.h (tty_display_info): Remove TN_max_pairs field
describing maximum number of terminal background/foreground color pairs.
* src/term.c (tty_default_color_capabilities, tty_setup_colors,
init_tty): Remove references to TN_max_pairs.
---
 src/term.c     | 6 ------
 src/termchar.h | 4 ----
 2 files changed, 10 deletions(-)

diff --git a/src/term.c b/src/term.c
index c067a86..b0ff9cb 100644
--- a/src/term.c
+++ b/src/term.c
@@ -2048,7 +2048,6 @@ TERMINAL does not refer to a text terminal.  */)
    to work around an HPUX compiler bug (?). See
    http://lists.gnu.org/archive/html/emacs-devel/2007-08/msg00410.html  */
 static int default_max_colors;
-static int default_max_pairs;
 static int default_no_color_video;
 static char *default_orig_pair;
 static char *default_set_foreground;
@@ -2066,7 +2065,6 @@ tty_default_color_capabilities (struct tty_display_info *tty, bool save)
       dupstring (&default_set_foreground, tty->TS_set_foreground);
       dupstring (&default_set_background, tty->TS_set_background);
       default_max_colors = tty->TN_max_colors;
-      default_max_pairs = tty->TN_max_pairs;
       default_no_color_video = tty->TN_no_color_video;
     }
   else
@@ -2075,7 +2073,6 @@ tty_default_color_capabilities (struct tty_display_info *tty, bool save)
       tty->TS_set_foreground = default_set_foreground;
       tty->TS_set_background = default_set_background;
       tty->TN_max_colors = default_max_colors;
-      tty->TN_max_pairs = default_max_pairs;
       tty->TN_no_color_video = default_no_color_video;
     }
 }
@@ -2095,7 +2092,6 @@ tty_setup_colors (struct tty_display_info *tty, int mode)
     {
       case -1:	 /* no colors at all */
 	tty->TN_max_colors = 0;
-	tty->TN_max_pairs = 0;
 	tty->TN_no_color_video = 0;
 	tty->TS_set_foreground = tty->TS_set_background = tty->TS_orig_pair = NULL;
 	break;
@@ -2113,7 +2109,6 @@ tty_setup_colors (struct tty_display_info *tty, int mode)
 	tty->TS_set_background = "\033[4%dm";
 #endif
 	tty->TN_max_colors = 8;
-	tty->TN_max_pairs = 64;
 	tty->TN_no_color_video = 0;
 	break;
     }
@@ -4135,7 +4130,6 @@ use the Bourne shell command 'TERM=...; export TERM' (C-shell:\n\
 	}
 
       tty->TN_max_colors = tgetnum ("Co");
-      tty->TN_max_pairs = tgetnum ("pa");
 
       tty->TN_no_color_video = tgetnum ("NC");
       if (tty->TN_no_color_video == -1)
diff --git a/src/termchar.h b/src/termchar.h
index e6e483e..cf061a9 100644
--- a/src/termchar.h
+++ b/src/termchar.h
@@ -149,10 +149,6 @@ struct tty_display_info
 
   int TN_max_colors;            /* "Co" -- number of colors.  */
 
-  /* "pa" -- max. number of color pairs on screen.  Not handled yet.
-     Could be a problem if not equal to TN_max_colors * TN_max_colors.  */
-  int TN_max_pairs;
-
   /* "op" -- SVr4 set default pair to its original value.  */
   const char *TS_orig_pair;
 
-- 
2.7.4

[PATCH 2/3] Support 24-bit terminal colors.

[Rami Ylimäki]

From: Rami Ylimäki <rjy@iki.fi>

Assume that number of terminal colors has been set to 16777216 if
terminal supports direct color mode. Detection of 24-bit color support
is added in next commit.

* lisp/term/tty-colors.el (tty-color-define): Convert color palette
index to pixel value on 16.7M color terminals.
(tty-color-24bit): Add new function to convert color palette index to
pixel value on 16.7M color terminals.
(tty-color-desc): Don't approximate colors on 16.7M color terminals.
* lisp/term/xterm.el (xterm-register-default-colors): Define all named
TTY colors on 16.7M color terminals.
---
 lisp/term/tty-colors.el | 19 +++++++++++++++++--
 lisp/term/xterm.el      |  8 ++++++++
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/lisp/term/tty-colors.el b/lisp/term/tty-colors.el
index 252a430..9cfe30a 100644
--- a/lisp/term/tty-colors.el
+++ b/lisp/term/tty-colors.el
@@ -824,6 +824,15 @@ A canonicalized color name is all-lower case, with any blanks removed."
 	(replace-regexp-in-string " +" "" (downcase color))
       color)))
 
+(defun tty-color-24bit (rgb)
+  "Return pixel value on 24-bit terminals. Return nil if RGB is
+nil or not on 24-bit terminal."
+  (when (and rgb (= (display-color-cells) 16777216))
+    (let ((r (lsh (car rgb) -8))
+	  (g (lsh (cadr rgb) -8))
+	  (b (lsh (nth 2 rgb) -8)))
+      (logior (lsh r 16) (lsh g 8) b))))
+
 (defun tty-color-define (name index &optional rgb frame)
   "Specify a tty color by its NAME, terminal INDEX and RGB values.
 NAME is a string, INDEX is typically a small integer used to send to
@@ -840,7 +849,10 @@ If FRAME is not specified or is nil, it defaults to the selected frame."
 	  (and rgb (or (not (listp rgb)) (/= (length rgb) 3))))
       (error "Invalid specification for tty color \"%s\"" name))
   (tty-modify-color-alist
-   (append (list (tty-color-canonicalize name) index) rgb) frame))
+   (append (list (tty-color-canonicalize name)
+		 (or (tty-color-24bit rgb) index))
+	   rgb)
+   frame))
 
 (defun tty-color-clear (&optional _frame)
   "Clear the list of supported tty colors for frame FRAME.
@@ -1013,7 +1025,10 @@ might need to be approximated if it is not supported directly."
        (let ((color (tty-color-canonicalize color)))
 	  (or (assoc color (tty-color-alist frame))
 	      (let ((rgb (tty-color-standard-values color)))
-		(and rgb (tty-color-approximate rgb frame)))))))
+		(and rgb
+		     (let ((pixel (tty-color-24bit rgb)))
+		       (or (and pixel (cons color (cons pixel rgb)))
+			   (tty-color-approximate rgb frame)))))))))
 
 (defun tty-color-gray-shades (&optional display)
   "Return the number of gray colors supported by DISPLAY's terminal.
diff --git a/lisp/term/xterm.el b/lisp/term/xterm.el
index 339d05d..e6d224d 100644
--- a/lisp/term/xterm.el
+++ b/lisp/term/xterm.el
@@ -930,6 +930,14 @@ versions of xterm."
     ;; are more colors to support, compute them now.
     (when (> ncolors 0)
       (cond
+       ((= ncolors 16777200) ; 24-bit xterm
+	;; all named tty colors
+	(let ((idx (length xterm-standard-colors)))
+	  (mapc (lambda (color)
+		  (unless (assoc (car color) xterm-standard-colors)
+		    (tty-color-define (car color) idx (cdr color))
+		    (setq idx (1+ idx))))
+		color-name-rgb-alist)))
        ((= ncolors 240)	; 256-color xterm
 	;; 216 non-gray colors first
 	(let ((r 0) (g 0) (b 0))
-- 
2.7.4

[PATCH 3/3] Let user turn 24-bit terminal colors on.

[Rami Ylimäki]

From: Rami Ylimäki <rjy@iki.fi>

ITU-T T.412 9.1.4 and ITU-T T.416 13.1.8 specify control function for
changing terminal foreground and background colors. One possible format
for the control function parameters is: 2:n:r:g:b, where 2 is color
access mode indicating direct RGB space, n is an indentifier that gives
detailed information about the color space and r, g, b are the color
values.

Most 24-bit terminals implement this function as 2;r;g;b. Color space
identifier has been omitted because of its complexity and rgb values are
assumed to be in range 0-255. Parameters are separated by semicolons
instead of colons for historical reasons.

The terminfo database supports only indexed color control functions and
can't be used to determine whether a terminal has implemented direct
color control functions.

However, this can be worked around by creating user defined functions
for setting 24-bit foreground and background colors. This can be done by
creating a terminfo source file with the required capabilities and
compiling a custom terminal type definition.

For example:

  $ cat xterm-24bit

  # Replace semicolons with colons in setab24 and setaf24 on terminals
  # that use ITU-T separators (iTerm2). A 24-bit integer (p1) is given
  # as a parameter to the control functions which calculate rgb
  # component values with following formulas:
  # r = p1 / 65536, g = (p1 / 256) & 255, b = p1 & 255
  xterm-24bit|xterm with 16777216 colors,
    use=xterm-256color,
    setab24=\E[48;2;%p1%{65536}%/%d;%p1%{256}%/%{255}%&%d;%p1%{255}%&%dm,
    setaf24=\E[38;2;%p1%{65536}%/%d;%p1%{256}%/%{255}%&%d;%p1%{255}%&%dm,

  $ tic -x -o ~/.terminfo xterm-24bit

  $ TERM=xterm-24bit emacs

* src/term.c (init_tty): Use 24-bit terminal colors if corresponding
foreground and background functions are present in terminal type
definition.
* src/tparam.h: Define prototype for tigetstr.
---
 src/term.c   | 14 ++++++++++++++
 src/tparam.h |  4 ++++
 2 files changed, 18 insertions(+)

diff --git a/src/term.c b/src/term.c
index b0ff9cb..9d1c3c1 100644
--- a/src/term.c
+++ b/src/term.c
@@ -4131,6 +4131,20 @@ use the Bourne shell command 'TERM=...; export TERM' (C-shell:\n\
 
       tty->TN_max_colors = tgetnum ("Co");
 
+#if TERMINFO
+      /* Non-standard support for 24-bit colors. */
+      {
+	const char* fg = tigetstr ("setaf24");
+	const char* bg = tigetstr ("setab24");
+	if (fg && bg && fg != (char *)-1 && bg != (char *)-1)
+	  {
+	    tty->TS_set_foreground = fg;
+	    tty->TS_set_background = bg;
+	    tty->TN_max_colors = 16777216;
+	  }
+      }
+#endif
+
       tty->TN_no_color_video = tgetnum ("NC");
       if (tty->TN_no_color_video == -1)
         tty->TN_no_color_video = 0;
diff --git a/src/tparam.h b/src/tparam.h
index 15664d6..8e34c9e 100644
--- a/src/tparam.h
+++ b/src/tparam.h
@@ -36,4 +36,8 @@ extern char PC;
 extern char *BC;
 extern char *UP;
 
+#if TERMINFO
+char *tigetstr(const char *);
+#endif
+
 #endif /* EMACS_TPARAM_H */
-- 
2.7.4

Re: [PATCH 3/3] Let user turn 24-bit terminal colors on.

[Filipe Silva]

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Thanks for this Rami,

I've being itching to get 24 bit colors in terminal emacs for years.

​

On Sun, Feb 12, 2017 at 8:05 AM, Rami Ylimäki <rami.ylimaki@vincit.fi>
wrote:

> From: Rami Ylimäki <rjy@iki.fi>
>
> ITU-T T.412 9.1.4 and ITU-T T.416 13.1.8 specify control function for
> changing terminal foreground and background colors. One possible format
> for the control function parameters is: 2:n:r:g:b, where 2 is color
> access mode indicating direct RGB space, n is an indentifier that gives
> detailed information about the color space and r, g, b are the color
> values.
>
> Most 24-bit terminals implement this function as 2;r;g;b. Color space
> identifier has been omitted because of its complexity and rgb values are
> assumed to be in range 0-255. Parameters are separated by semicolons
> instead of colons for historical reasons.
>
> The terminfo database supports only indexed color control functions and
> can't be used to determine whether a terminal has implemented direct
> color control functions.
>
> However, this can be worked around by creating user defined functions
> for setting 24-bit foreground and background colors. This can be done by
> creating a terminfo source file with the required capabilities and
> compiling a custom terminal type definition.
>
> For example:
>
>   $ cat xterm-24bit
>
>   # Replace semicolons with colons in setab24 and setaf24 on terminals
>   # that use ITU-T separators (iTerm2). A 24-bit integer (p1) is given
>   # as a parameter to the control functions which calculate rgb
>   # component values with following formulas:
>   # r = p1 / 65536, g = (p1 / 256) & 255, b = p1 & 255
>   xterm-24bit|xterm with 16777216 colors,
>     use=xterm-256color,
>     setab24=\E[48;2;%p1%{65536}%/%d;%p1%{256}%/%{255}%&%d;%p1%{255}%&%dm,
>     setaf24=\E[38;2;%p1%{65536}%/%d;%p1%{256}%/%{255}%&%d;%p1%{255}%&%dm,
>
>   $ tic -x -o ~/.terminfo xterm-24bit
>
>   $ TERM=xterm-24bit emacs
>
> * src/term.c (init_tty): Use 24-bit terminal colors if corresponding
> foreground and background functions are present in terminal type
> definition.
> * src/tparam.h: Define prototype for tigetstr.
> ---
>  src/term.c   | 14 ++++++++++++++
>  src/tparam.h |  4 ++++
>  2 files changed, 18 insertions(+)
>
> diff --git a/src/term.c b/src/term.c
> index b0ff9cb..9d1c3c1 100644
> --- a/src/term.c
> +++ b/src/term.c
> @@ -4131,6 +4131,20 @@ use the Bourne shell command 'TERM=...; export
> TERM' (C-shell:\n\
>
>        tty->TN_max_colors = tgetnum ("Co");
>
> +#if TERMINFO
> +      /* Non-standard support for 24-bit colors. */
> +      {
> +       const char* fg = tigetstr ("setaf24");
> +       const char* bg = tigetstr ("setab24");
> +       if (fg && bg && fg != (char *)-1 && bg != (char *)-1)
> +         {
> +           tty->TS_set_foreground = fg;
> +           tty->TS_set_background = bg;
> +           tty->TN_max_colors = 16777216;
> +         }
> +      }
> +#endif
> +
>        tty->TN_no_color_video = tgetnum ("NC");
>        if (tty->TN_no_color_video == -1)
>          tty->TN_no_color_video = 0;
> diff --git a/src/tparam.h b/src/tparam.h
> index 15664d6..8e34c9e 100644
> --- a/src/tparam.h
> +++ b/src/tparam.h
> @@ -36,4 +36,8 @@ extern char PC;
>  extern char *BC;
>  extern char *UP;
>
> +#if TERMINFO
> +char *tigetstr(const char *);
> +#endif
> +
>  #endif /* EMACS_TPARAM_H */
> --
> 2.7.4
>
>
>

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Re: [PATCH 3/3] Let user turn 24-bit terminal colors on.

[Rami Ylimäki]

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2017-02-12 12:05 GMT+02:00 Rami Ylimäki <rami.ylimaki@vincit.fi>:

> +#if TERMINFO
>

The #if should be replaced with #ifdef or the build fails if terminfo isn't
available.

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Re: [PATCH v2] Support 24-bit terminal colors.

[Eli Zaretskii]

> From: Rami Ylimäki <rami.ylimaki@vincit.fi>
> Date: Sun, 12 Feb 2017 12:05:27 +0200
> 
> I have tested these changes on gnome-terminal/Ubuntu and iTerm2/OSX.
> 
> Rami Ylimäki (3):
>   Remove unused terminal color pair count.
>   Support 24-bit terminal colors.
>   Let user turn 24-bit terminal colors on.
> 
>  lisp/term/tty-colors.el | 19 +++++++++++++++++--
>  lisp/term/xterm.el      |  8 ++++++++
>  src/term.c              | 20 ++++++++++++++------
>  src/termchar.h          |  4 ----
>  src/tparam.h            |  4 ++++
>  5 files changed, 43 insertions(+), 12 deletions(-)

Thanks.  This looks very good.  A couple of comments:

 . Please prepare a NEWS entry for this feature.
 . It seems like you dropped the code to support the --color=
   command-line argument, which was part of your original submission?
   All the other color TTY modes support --color=NUM, so I think we
   should also support --color=16777216, and perhaps also --color-24bit.
 . If you agree to add the code for the previous item, the Emacs user
   manual should need an update (node "Colors X", where the --color
   option is described).

Thanks again for working on this.

Re: [PATCH v2] Support 24-bit terminal colors.

[Rami Ylimäki]

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2017-02-12 22:47 GMT+02:00 Eli Zaretskii <eliz@gnu.org>:
>
>  . Please prepare a NEWS entry for this feature.
>  . It seems like you dropped the code to support the --color=
>    command-line argument, which was part of your original submission?
>    All the other color TTY modes support --color=NUM, so I think we
>    should also support --color=16777216, and perhaps also --color-24bit.
>

I'll write the NEWS entry but I'm afraid that fixing the --color=NUM option
would require too much effort right now.

The manual is too optimistic when it states that "Emacs might be able to
turn on a color mode for 8, 16, 88, or 256 as the value of NUM". In
reality, only -1, 0 and 8 are supported. The 16, 88, and 256 color modes
can only be enabled based on current terminal capabilities and this is now
true for the 16M color mode as well.

The problems of handling --color=NUM can be seen when colors are
downgraded, because color and face pixel values aren't updated. For
example, "M-x list-faces-display" produces different results with
"TERM=xterm emacs -Q -nw --color=8" and "TERM=xterm-256color emacs -Q -nw
--color=8". This is why I'd like to treat the --color option as a separate
issue.

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Re: [PATCH v2] Support 24-bit terminal colors.

[Eli Zaretskii]

> From: Rami Ylimäki <rami.ylimaki@vincit.com>
> Date: Mon, 13 Feb 2017 00:53:47 +0200
> Cc: emacs-devel@gnu.org
> 
>  . Please prepare a NEWS entry for this feature.
>  . It seems like you dropped the code to support the --color=
>  command-line argument, which was part of your original submission?
>  All the other color TTY modes support --color=NUM, so I think we
>  should also support --color=16777216, and perhaps also --color-24bit.
> 
> I'll write the NEWS entry but I'm afraid that fixing the --color=NUM option would require too much effort right
> now.
> 
> The manual is too optimistic when it states that "Emacs might be able to turn on a color mode for 8, 16, 88, or
> 256 as the value of NUM". In reality, only -1, 0 and 8 are supported. The 16, 88, and 256 color modes can only
> be enabled based on current terminal capabilities and this is now true for the 16M color mode as well.
> 
> The problems of handling --color=NUM can be seen when colors are downgraded, because color and face
> pixel values aren't updated. For example, "M-x list-faces-display" produces different results with "TERM=xterm
> emacs -Q -nw --color=8" and "TERM=xterm-256color emacs -Q -nw --color=8". This is why I'd like to treat the
> --color option as a separate issue.

Fair enough, thanks.