Data commit

Task/Pentagram/Sidef/pentagram.sidef

@@ -0,0 +1,29 @@
+func pentagram(dim=200, sides=5) {
+    var pentagram = <<-EOT
+    <?xml version="1.0" standalone="no" ?>
+    <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.0//EN"
+    "http://www.w3.org/TR/2001/PR-SVG-20010719/DTD/svg10.dtd">
+    <svg height="#{dim*2}" width="#{dim*2}" style="" xmlns="http://www.w3.org/2000/svg">
+    <rect height="100%" width="100%" style="fill:black;" />
+    EOT
+
+    func cis(x) {
+        cos(x) + sin(x).i
+    }
+
+    func pline(q) {
+        <<-EOT
+        <polyline points="#{[q..., q[0], q[1]].map{|n| '%0.3f' % n }.join(' ')}"
+        style="fill:blue; stroke:white; stroke-width:3;"
+        transform="translate(#{dim}, #{dim}) rotate(-18)" />
+        EOT
+    }
+
+    var v = sides.range.map {|k| 0.9 * dim * cis(k * Num.tau / sides) }
+    pentagram += pline([v[range(0, v.end, 2)], v[range(1, v.end, 2)]].map{.reals})
+    pentagram += '</svg>'
+
+    return pentagram
+}
+
+say pentagram()