Add Braille canvas and basic line plots

build.ss

@@ -0,0 +1,8 @@
+#!/usr/bin/env gxi
+
+(import :std/build-script)
+
+(defbuild-script
+  '("uniplot/braille"
+    "uniplot/lineplot")
+  optimize: #t)

demo.ss

@@ -0,0 +1,13 @@
+#!/usr/bin/env gxi
+
+(export main)
+
+(import :std/misc/string
+	:dlozeve/fancy/format
+	:dlozeve/uniplot/lineplot)
+
+(def (main . args)
+  (let* ((xs (iota 1000 0 0.01))
+	 (ys1 (map cos xs))
+	 (ys2 (map sin xs)))
+    (displayln (line-plot [xs ys1 ys2]))))

uniplot/braille.ss

@@ -0,0 +1,60 @@
+(export #t)
+
+(import :std/iter
+	:std/misc/list
+	:std/misc/string
+	:gerbil/gambit/hvectors
+	:gerbil/gambit/bits
+	:dlozeve/fancy/format)
+
+(def +braille-signs+
+  (list->u8vector (map (lambda (c) (- (char->integer c) (char->integer #\⠀)))
+		       (string->list "⡀⠄⠂⠁⢀⠠⠐⠈"))))
+
+(def (make-braille-canvas n m)
+  (def canvas-n (+ (quotient n 4) (if (zero? (remainder n 4)) 0 1)))
+  (def canvas-m (+ (quotient m 2) (if (zero? (remainder m 2)) 0 1)))
+  (def vec (make-vector canvas-n #f))
+  (for ((i (in-range canvas-n)))
+    (vector-set! vec i (make-u8vector canvas-m 0)))
+  vec)
+
+(def (braille-canvas-ref canvas i j)
+  (def c (u8vector-ref (vector-ref canvas (quotient i 4)) (quotient j 2)))
+  (def offset (u8vector-ref +braille-signs+
+			    (+ (remainder i 4) (* 4 (remainder j 2)))))
+  (any-bits-set? c offset))
+
+(def (braille-canvas-set! canvas i j v)
+  (def old-offset (u8vector-ref (vector-ref canvas (quotient i 4)) (quotient j 2)))
+  (def update-offset (u8vector-ref +braille-signs+
+				   (+ (remainder i 4) (* 4 (remainder j 2)))))
+  (def new-char (if v
+		  (bitwise-ior old-offset update-offset)
+		  (bitwise-and old-offset (bitwise-not update-offset))))
+  (u8vector-set! (vector-ref canvas (quotient i 4)) (quotient j 2) new-char))
+
+(def (canvas->string canvas)
+  (def chars (for/collect ((i (in-range (vector-length canvas) 0 -1)))
+	       (def row (vector-ref canvas (1- i)))
+	       (for/collect ((j (in-range (u8vector-length row))))
+		 (integer->char (+ (char->integer #\⠀) (u8vector-ref row j))))))
+  (list->string (flatten (map (lambda (l) (append1 l #\newline)) chars))))
+
+(def (indexf pred . lsts)
+  (find pred (apply map list lsts)))
+
+(def (canvases->string canvases (colors '(red green cyan yellow magenta white)))
+  (def canvases-str (map canvas->string canvases))
+  (def size (string-length (car canvases-str)))
+  (apply str
+    (for/collect ((i (in-range size)))
+      (let* ((characters (map (lambda (s) (string-ref s i)) canvases-str))
+	     (char-color (indexf (lambda (x) (or (char=? (car x) #\newline)
+					    (char>? (car x) #\⠀)))
+				 characters colors)))
+	(if char-color
+	  (str (graphics-style [(cadr char-color)])
+	       (car char-color)
+	       (graphics-style))
+	  #\⠀)))))

uniplot/lineplot.ss

@@ -0,0 +1,42 @@
+(export #t)
+
+(import :std/iter
+	:std/misc/list
+	:std/misc/string
+	:dlozeve/uniplot/braille
+	:dlozeve/fancy/format)
+
+(def (scale-fn lo hi)
+  (lambda (x) (/ (- x lo) (- hi lo))))
+
+(def (draw-canvas xs ys x-scale-fn y-scale-fn width: (width 160) height: (height 80))
+  (def canvas (make-braille-canvas (1+ height) (1+ width)))
+  (for ((x xs) (y ys))
+    (braille-canvas-set! canvas
+			 (inexact->exact (floor (* height (y-scale-fn y))))
+			 (inexact->exact (floor (* width (x-scale-fn x))))
+			 #t))
+  canvas)
+
+(def (line-plot lsts width: (width 160) height: (height 80))
+  (match lsts
+    ([ys] (canvas->string
+	   (draw-canvas (iota (length ys)) ys
+			(scale-fn 0 (length ys))
+			(scale-fn (apply min ys) (apply max ys))
+			width: width height: height)))
+    ([xs ys] (canvas->string
+	      (draw-canvas xs ys
+			   (scale-fn (apply min xs) (apply max xs))
+			   (scale-fn (apply min ys) (apply max ys))
+			   width: width height: height)))
+    ([xs . yss]
+     (canvases->string
+      (let* ((x-scale-fn (scale-fn (apply min xs) (apply max xs)))
+	     (all-ys (flatten yss))
+	     (min-ys (apply min all-ys))
+	     (max-ys (apply max all-ys))
+	     (y-scale-fn (scale-fn min-ys max-ys)))
+	(for/collect ((ys yss))
+	  (draw-canvas xs ys x-scale-fn y-scale-fn
+		       width: width height: height)))))))