--- /dev/null
+;;; Load GIMP Gradients. Kind of.
+;;; 2014
+
+(use-modules (ice-9 match)
+ (ice-9 rdelim)
+
+ (rnrs enums)
+ (srfi srfi-9)
+ (srfi srfi-26))
+
+(define +default-steps+ 1024)
+
+
+;; returna list of ((#(left-pos r g b) #(right-pos r g b)))
+;; ignore alpha, blending function, midpoint... whatever, for now.
+(define (parse-gradient file-name)
+ (call-with-input-file file-name
+ (lambda (instream)
+ (read-line instream) ; Gimp Gradient
+ (let* ((name (read-line instream))
+ (segments (string->number (read-line instream))))
+ (let loop ((next-line (read-line instream))
+ (segments (list)))
+ (if (eof-object? next-line)
+ (reverse segments)
+ (let ((bits (string-split next-line #\space)))
+ (format #t "bits (~A): ~A~%" (length bits) bits)
+ (match (map string->number bits)
+ ((left-stop mid right-stop lr lg lb la rr rg rb ra blend color)
+ (loop (read-line instream)
+ (cons (list (vector left-stop lr lg lb)
+ #;(vector mid mr mg mb)
+ (vector right-stop rr rg rb))
+ segments)))))))))))
+
+(define (segment->rgb segment total-steps)
+ (match segment
+ ((#(l lr lg lb) #(r rr rg rb))
+ (linear-blend lr lg lb rr rg rb
+ (inexact->exact (floor (* total-steps (- r l))))))))
+
+(define (segments->rgb segments total-steps)
+ (apply append (map (cut segment->rgb <> total-steps) segments)))
+
+(define* (linear-blend r1 g1 b1 r2 g2 b2 steps)
+ (let ((rd (/ (- r2 r1) steps))
+ (gd (/ (- g2 g1) steps))
+ (bd (/ (- g2 g1) steps)))
+ (let loop ((remaining steps)
+ (colors (list)))
+ (if (= remaining 0)
+ (reverse colors)
+ (let ((step (- steps remaining)))
+ (loop (1- remaining)
+ (cons (vector (+ r1 (* rd step))
+ (+ g1 (* gd step))
+ (+ b1 (* bd step)))
+ colors)))))))
+
+
+(use-modules (ice-9 rdelim)
+ (ice-9 match)
+ (ice-9 receive)
+ (srfi srfi-1)
+ (ice-9 format))
+
+(system "stty -F /dev/ttyACM0 cs8 115200 ignbrk -brkint -icrnl -imaxbel -opost -onlcr -isig -icanon -iexten -echo -echoe -echok -echoctl -echoke noflsh -ixon -crtscts")
+
+(set! *random-state* (random-state-from-platform))
+
+(define out (open-file "/dev/ttyACM0" "w0+"))
+
+(define pi 3.14159)
+
+(define (deg->rad degrees)
+ (* degrees (/ pi 180)))
+
+(define (hsv->rgb h s v)
+ (let* ((chroma (* v s))
+ (hue' (/ h (/ pi 3)))
+ (x (* chroma (- 1 (abs (- (euclidean-remainder hue' 2) 1)))))
+ (m (- v chroma)))
+ (receive (r₁ g₁ b₁)
+ (case (inexact->exact (floor hue'))
+ ((0) (values chroma x 0))
+ ((1) (values x chroma 0))
+ ((2) (values 0 chroma x))
+ ((3) (values 0 x chroma))
+ ((4) (values x 0 chroma))
+ ((5) (values chroma 0 x)))
+ (values (+ r₁ m) (+ g₁ m) (+ b₁ m)))))
+
+;; (define ts (make-termios-struct))
+;; ;; Get the current setings of the serial-device.
+;; (tc-get-attr! out ts)
+;; (cf-set-speed! ts termios-B9600)
+;; (tc-set-attr out ts)
+
+(sleep 3)
+
+(define tick-increment (/ (* 2 pi) (* 360 1)))
+
+(define (random-ticks n) (* tick-increment (random n)))
+
+(define last-pulse (car (gettimeofday)))
+
+
+(while #t
+ (for-each (lambda (color)
+ (match color
+ (#(r g b)
+ (let ((r' (inexact->exact (round (* r 255))))
+ (g' (inexact->exact (round (* g 255))))
+ (b' (inexact->exact (round (* b 255)))))
+ (format out "~A,~A,~A,0~c" r' g' b' #\return)
+ (format out "~A,~A,~A,1~c" r' g' b' #\return)
+ (usleep 450000)))))
+ (segments->rgb (parse-gradient "/usr/share/gimp/2.0/gradients/Cold_Steel.ggr") 1024)))