Hilbert curve: Difference between revisions

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 </pre>
+=={{header|JavaScript}}==
+An implementation of GO. Prints an SVG string that can be read in a browser.
+<lang javascript>const hilbert = (width, spacing, points) => (x,y,lg,i1, i2, f) => {
+  if (lg === 1) {
+    const px = (width - x) * spacing;
+    const py = (width -y ) * spacing;
+    points.push(px, py);
+    return;
+  }
+  lg >>= 1;
+  f(x+i1*lg, y+i1*lg, lg, i1, 1-i2, f);
+  f(x+i2*lg, y+(1-i2)*lg, lg, i1, i2, f);
+  f(x+(1-i1)*lg, y+(1-i1)*lg, lg, i1, i2, f);
+  f(x+(1-i2)*lg, y+i2*lg, lg, 1-i1, i2, f);
+  return points;
+};
+/**
+ * Draw a hilbert curve of the given order.
+ * Outputs a svg string. Save the string as a .svg file and open in a browser.
+ * @param {!Number} order
+ */
+const drawHilbert = order => {
+  if (!order || order < 1) {
+    throw 'You need to give a valid positive integer';
+  } else {
+    order = Math.floor(order);
+  }
+  // Curve Constants
+  const width = 2**order;
+  const space = 10;
+  // SVG Setup
+  const size = 500;
+  const stroke = 2;
+  const col = "red";
+  const fill = "transparent";
+  // Prep and run function
+  const f = hilbert(width, space, []);
+  const points = f(0, 0, width, 0, 0, f);
+  const path = points.join(' ');
+  console.log(
+`<svg xmlns="http://www.w3.org/2000/svg"
+    width="${size}"
+    height="${size}"
+    viewBox="${space / 2} ${space / 2} ${width * space} ${width * space}">
+  <path d="M${path}" stroke-width="${stroke}" stroke="${col}" fill="${fill}"/>
+</svg>`);
+};
+drawHilbert(6);
+</lang>
 =={{header|Julia}}==