Re: highlight failed part of isearch input

[Juri Linkov]

> I don't care which hue (green, red, blue, magenta, cyan, yellow) we use, but
> the difference in value (brightness) from the normal background should be
> slight - noticeable, but slight.

I agree that IndianRed1 is too loud color, but OTOH Plum is too mild and
lifeless.  However, taking into account all your arguments it is possible
to find a suitable color on the whole color space.

First, I think we should use red hue since this is used for error strings
usually.  As for lightness, on a light background it is better to shift it
to the maximum, because darker colors looks dirty on a light background.
So we are left with the single axis of saturation.  There we have three
named colors: "IndianRed1", "brown1" and "RosyBrown1".  First two are
too saturated, and "RosyBrown1" (#ffc1c1) is too close to the default
background color.  So I think we could use a color with the numeric notation
#ff8888.  This color looks good, and black text on it is readable.

Here is the comparison of #ff8888 (Current) with Plum (Old):

For a dark background, I think we should use the maximal saturation, and
pick a color on the lightness-darkness axis.  The complement for #ff8888
on this axis is "red4" which is dark enough.  I checked that it looks good
on a dark background:

Index: lisp/isearch.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/isearch.el,v
retrieving revision 1.310
diff -c -r1.310 isearch.el
*** lisp/isearch.el     12 Feb 2008 00:50:44 -0000      1.310
--- lisp/isearch.el     24 Feb 2008 17:30:47 -0000
***************
*** 231,238 ****
    :group 'basic-faces)
  (defvar isearch 'isearch)
  
! (defface isearch-fail '((t (:foreground "Black" :background "Plum")))
    "Face for highlighting failed part in Isearch echo-area message."
    :group 'isearch)
  
  (defcustom isearch-lazy-highlight t
--- 231,250 ----
    :group 'basic-faces)
  (defvar isearch 'isearch)
  
! (defface isearch-fail
!   '((((class color) (min-colors 88) (background light))
!      (:background "#ff8888"))
!     (((class color) (min-colors 88) (background dark))
!      (:background "red4"))
!     (((class color) (min-colors 16))
!      (:background "red"))
!     (((class color) (min-colors 8))
!      (:background "red"))
!     (((class color grayscale))
!      :foreground "grey")
!     (t (:inverse-video t)))
    "Face for highlighting failed part in Isearch echo-area message."
+   :version "23.1"
    :group 'isearch)
  
  (defcustom isearch-lazy-highlight t

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