Data commit

Task/Yin-and-yang/UNIX-Shell/yin-and-yang.sh

@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+in_circle() { #(cx, cy, r, x y)
+  # return true if the point (x,y) lies within the circle of radius r centered
+  # on (cx,cy)
+  # (but really scaled to an ellipse with vertical minor semiaxis r and
+  # horizontal major semiaxis 2r)
+  local -i cx=$1 cy=$2 r=$3 x=$4 y=$5
+  local -i dx dy
+  (( dx=(x-cx)/2, dy=y-cy, dx*dx + dy*dy <= r*r ))
+}
+
+taijitu() { #radius
+  local -i radius=${1:-17}
+  local -i x1=0 y1=0 r1=radius            # outer circle
+  local -i x2=0 y2=-radius/2 r2=radius/6  # upper eye
+  local -i x3=0 y3=-radius/2 r3=radius/2  # upper half
+  local -i x4=0 y4=+radius/2 r4=radius/6  # lower eye
+  local -i x5=0 y5=+radius/2 r5=radius/2  # lower half
+  local -i x y
+  for (( y=radius; y>=-radius; --y )); do
+    for (( x=-2*radius; x<=2*radius; ++x)); do
+      if ! in_circle $x1 $y1 $r1 $x $y; then
+        printf ' '
+      elif in_circle $x2 $y2 $r2 $x $y; then
+        printf '#'
+      elif in_circle $x3 $y3 $r3 $x $y; then
+        printf '.'
+      elif in_circle $x4 $y4 $r4 $x $y; then
+        printf '.'
+      elif in_circle $x5 $y5 $r5 $x $y; then
+        printf '#'
+      elif (( x <= 0 )); then
+        printf '.'
+      else
+        printf '#'
+      fi
+    done
+    printf '\n'
+  done
+}