+ (when (> ncolors 0)
+ (cond
+ ((= ncolors 240) ; 256-color rxvt
+ ;; 216 non-gray colors first
+ (let ((r 0) (g 0) (b 0))
+ (while (> ncolors 24)
+ ;; This and other formulae taken from 256colres.pl and
+ ;; 88colres.pl in the xterm distribution.
+ (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)))))
+ (setq b (1+ b))
+ (if (> b 5)
+ (setq g (1+ g)
+ b 0))
+ (if (> g 5)
+ (setq r (1+ r)
+ g 0))
+ (setq ncolors (1- ncolors))))
+ ;; Now the 24 gray colors
+ (while (> ncolors 0)
+ (setq color (rxvt-rgb-convert-to-16bit (+ 8 (* (- 24 ncolors) 10))))
+ (tty-color-define (format "color-%d" (- 256 ncolors))
+ (- 256 ncolors)
+ (list color color color))
+ (setq ncolors (1- ncolors))))
+
+ ((= ncolors 72) ; rxvt-unicode
+ ;; 64 non-gray colors
+ (let ((levels '(0 139 205 255))
+ (r 0) (g 0) (b 0))
+ (while (> ncolors 8)
+ (tty-color-define (format "color-%d" (- 88 ncolors))
+ (- 88 ncolors)
+ (mapcar 'rxvt-rgb-convert-to-16bit
+ (list (nth r levels)
+ (nth g levels)
+ (nth b levels))))
+ (setq b (1+ b))
+ (if (> b 3)
+ (setq g (1+ g)
+ b 0))
+ (if (> g 3)
+ (setq r (1+ r)
+ g 0))
+ (setq ncolors (1- ncolors))))
+ ;; Now the 8 gray colors
+ (while (> ncolors 0)
+ (setq color (rxvt-rgb-convert-to-16bit
+ (floor
+ (if (= ncolors 8)
+ 46.36363636
+ (+ (* (- 8 ncolors) 23.18181818) 69.54545454)))))
+ (tty-color-define (format "color-%d" (- 88 ncolors))
+ (- 88 ncolors)
+ (list color color color))
+ (setq ncolors (1- ncolors))))
+ (t (error "Unsupported number of rxvt colors (%d)" (+ 16 ncolors)))))