Re: Diff mode faces

[Juri Linkov <juri@jurta.org>]

>> Cc: Eli Zaretskii <eliz@gnu.org>, emacs-devel@gnu.org
>> From: merlyn@stonehenge.com (Randal L. Schwartz)
>> Date: 18 Jun 2005 08:27:12 -0700
>> 
>> Is there no way to switch automatically to a proper set of darker
>> colors when the main text is black instead of white?
>
> Yes, it's called background-mode.

I see there is one problem with background-mode on tty.  Unlike X,
on tty Emacs doesn't adjust background-mode after changing the
background color with any of the known methods: `set-background-color'
command, or customizing the background color of the default face.

It seems the correct place to fix this is `modify-frame-parameters'.
The call to Qframe_update_face_colors is duplicated from the function
`update_face_from_frame_parameter' in the patch below.  With this change
`frame-set-background-mode' gets called, so it updates background-mode
after every change of the background color on tty.

Index: src/frame.c
===================================================================
RCS file: /cvsroot/emacs/emacs/src/frame.c,v
retrieving revision 1.316
diff -u -r1.316 frame.c
--- src/frame.c	10 Jun 2005 02:22:11 -0000	1.316
+++ src/frame.c	19 Jun 2005 11:42:05 -0000
@@ -2313,6 +2313,13 @@
 	  prop = parms[i];
 	  val = values[i];
 	  store_frame_param (f, prop, val);
+
+	  if (EQ (prop, Qbackground_color)) {
+	    /* Changing the background color might change the background
+	       mode, so that we have to load new defface specs.  Call
+	       frame-update-face-colors to do that.  */
+	    call1 (Qframe_update_face_colors, frame);
+	  }
 	}
     }

Index: src/dispextern.h
===================================================================
RCS file: /cvsroot/emacs/emacs/src/dispextern.h,v
retrieving revision 1.202
diff -u -r1.202 dispextern.h
--- src/dispextern.h	17 Jun 2005 14:02:03 -0000	1.202
+++ src/dispextern.h	19 Jun 2005 11:43:31 -0000
@@ -2793,6 +2793,7 @@
 int merge_faces P_ ((struct frame *, Lisp_Object, int, int));
 int compute_char_face P_ ((struct frame *, int, Lisp_Object));
 void free_all_realized_faces P_ ((Lisp_Object));
+extern Lisp_Object Qframe_update_face_colors;
 extern Lisp_Object Qforeground_color, Qbackground_color;
 extern char unspecified_fg[], unspecified_bg[];
 void free_realized_multibyte_face P_ ((struct frame *, int));

-- 
Juri Linkov
http://www.jurta.org/emacs/