fix led-set-all and add usage of led-frame to README

README.md

@@ -14,7 +14,14 @@ Interact with the Novation Launchpad from within Clojure.
     (led-set grid 1 2 3) ; yellow
     (led-set grid 1 2 0) ; off
     (on-action grid :handler-name (fn [event x y] (led-set grid x y
-    (if (= :press event) 1 0))))
+        (if (= :press event) 1 0))))
+
+    ;; Chessboard pattern
+    (led-frame lp
+       (into {}
+         (for [x (range 8)
+               y (range 8)]
+           [[x y] (if (zero? (rem (+ x y) 2)) 1 2) ] )))
 
     ;; Interact with the peripheral circular buttons using the
     ;; MetaKeys protocol:

src/overtone/device/launchpad.clj

@@ -153,7 +153,11 @@
   (on-action [this key f]   ; currently ignoring key
     (swap! callbacks assoc :grid-handler f))
   (led-set-all [this colour]
-    (led-frame this (repeat 8 (repeat 8 colour))))
+    (led-frame this
+               (into {[0 0] 1}
+                     (for [y (range 8)
+                           x (range 8)]
+                       [[x y] colour]))))
   (led-set [this x y colour]
     (midi-note-on launchpad-out (coords->midi-note x y) (colour-single colour palette)))
   (led-frame [this leds]