[Example] Infinite Circles by Jack B. Du

app/examples/infinite-circles.recho.js

@@ -0,0 +1,76 @@
+/**
+ * @title Infinite Circles
+ * @author Jack B. Du
+ * @github jackbdu
+ * @created 2025-10-13
+ * @pull_request 162
+ * @thumbnail_start 33
+ */
+
+/**
+ * ============================================================================
+ * =                         Infinite Circles                                 =
+ * ============================================================================
+ */
+
+const backgroundChars = '{------}';
+const foregroundChars = '{CIRCLE}';
+
+const circleFrequency = recho.number(4, {min: 1, max: 6, step: 1});
+const animationRate = recho.number(1, {min: 1, max: 4, step: 1});
+
+const cols = 75;
+const rows = 18;
+const aspectRatio = cols/rows*0.5;
+
+const frameRate = 60;
+const loopFrames = Math.floor(30/animationRate);
+const frameCount = recho.interval(1000/frameRate);
+const progress = (frameCount) => frameCount%loopFrames/loopFrames;
+
+const TAU = Math.PI*2;
+
+//➜ {---CLE}{------}{CIRC--}{---CLE}{CIRCLE}{CIRCLE}{------}{CIRC--}{--RCLE}{--
+//➜ ---}{CIR---}{CIRCLE}{----LE}{CIRCLE}{CIRCLE}{CIRCLE}{----LE}{CI----}{CIRC--
+//➜ {-IRCLE}{---CLE}{------}{CIRCL-}{------}{-----E}{CIRC--}{--RCLE}{----LE}{C-
+//➜ --E}{C-----}{CIR---}{-IRCLE}{------}{------}{---CLE}{C-----}{CIRC--}{-IRCL-
+//➜ {CIRCL-}{-IRCLE}{---CLE}{C-----}{CIRCLE}{CI----}{-IRCLE}{----LE}{C----E}{CI
+//➜ CLE}{-----E}{C-----}{CIR---}{-IRCLE}{CIRCLE}{C-----}{CIRC--}{-IRCL-}{--RCLE
+//➜ {CIRC--}{CIRCL-}{--RCLE}{---CLE}{CI----}{CIRCLE}{----LE}{-----E}{CI----}{CI
+//➜ CLE}{----LE}{-----E}{CI----}{CIR---}{------}{CIRC--}{CIRCL-}{--RCLE}{---CLE
+//➜ {CIR---}{CIRC--}{-IRCL-}{--RCLE}{----LE}{----LE}{-----E}{C-----}{CI----}{CI
+//➜ CLE}{----LE}{-----E}{C-----}{CI----}{CIR---}{CIRC--}{-IRCL-}{--RCLE}{---CLE
+//➜ {CIR---}{CIRC--}{-IRCL-}{--RCLE}{----LE}{----LE}{-----E}{C-----}{CI----}{CI
+//➜ CLE}{----LE}{-----E}{CI----}{CIR---}{------}{CIRC--}{CIRCL-}{--RCLE}{---CLE
+//➜ {CIRC--}{CIRCL-}{--RCLE}{---CLE}{CI----}{CIRCLE}{----LE}{-----E}{CI----}{CI
+//➜ CLE}{-----E}{C-----}{CIR---}{-IRCLE}{CIRCLE}{C-----}{CIRC--}{-IRCL-}{--RCLE
+//➜ {CIRCL-}{-IRCLE}{---CLE}{C-----}{CIRCLE}{CI----}{-IRCLE}{----LE}{C----E}{CI
+//➜ --E}{C-----}{CIR---}{-IRCLE}{------}{------}{---CLE}{C-----}{CIRC--}{-IRCL-
+//➜ {-IRCLE}{---CLE}{------}{CIRCL-}{------}{-----E}{CIRC--}{--RCLE}{----LE}{C-
+//➜ ---}{CIR---}{CIRCLE}{----LE}{CIRCLE}{CIRCLE}{CIRCLE}{----LE}{CI----}{CIRC--
+{
+  const text = new Array(rows).fill(0).map((_,r,rowArray)=>{
+
+    return new Array(cols).fill(0).map((_,c,colArray)=>{
+
+      const t = progress(frameCount);
+      const y = r/rowArray.length-0.5;
+      const x = (c/colArray.length-0.5)*aspectRatio;
+
+      const backgroundCharOffset = r*Math.floor(backgroundChars.length/2);
+      const backgroundCharIndex = (c+backgroundCharOffset)%backgroundChars.length;
+      const foregroundCharOffset = r*Math.floor(foregroundChars.length/2);
+      const foregroundCharIndex = (c+foregroundCharOffset)%foregroundChars.length;
+
+      const radius = Math.sqrt(x*x+y*y);
+      const char = Math.sin(radius*TAU*circleFrequency+t*TAU) > 0 ?
+        backgroundChars[backgroundCharIndex] : foregroundChars[foregroundCharIndex];
+
+      return char;
+
+    }).join('');
+
+  }).join('\n');
+
+  echo(text);
+}