bug#14078: [PATCH] Fix 256 color mapping in rxvt.el

[oblique <psyberbits@gmail.com>]

Color mapping was wrong, I use the same way xterm.el does it.
---
 lisp/term/rxvt.el | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/lisp/term/rxvt.el b/lisp/term/rxvt.el
index 0e026a8..6a62cff 100644
--- a/lisp/term/rxvt.el
+++ b/lisp/term/rxvt.el
@@ -201,7 +201,7 @@
 
 (defun rxvt-rgb-convert-to-16bit (prim)
   "Convert an 8-bit primary color value PRIM to a corresponding 16-bit value."
-  (min 65535 (round (* (/ prim 255.0) 65535.0))))
+  (logior prim (lsh prim 8)))
 
 (defun rxvt-register-default-colors ()
   "Register the default set of colors for rxvt or compatible emulator.
@@ -233,9 +233,10 @@ for the currently selected frame."
 	    (tty-color-define (format "color-%d" (- 256 ncolors))
 			      (- 256 ncolors)
 			      (mapcar 'rxvt-rgb-convert-to-16bit
-				      (list (round (* r 42.5))
-					    (round (* g 42.5))
-					    (round (* b 42.5)))))
+                                      (list (if (zerop r) 0 (+ (* r 40) 55))
+                                            (if (zerop g) 0 (+ (* g 40) 55))
+                                            (if (zerop b) 0 (+ (* b 40) 55)))))
+
 	    (setq b (1+ b))
 	    (if (> b 5)
 		(setq g (1+ g)
-- 
1.8.1.5