Data commit

Task/Koch-curve/Java/koch-curve.java

@@ -0,0 +1,77 @@
+import java.awt.Point;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.Arrays;
+import java.util.ArrayList;
+import java.util.List;
+
+public final class KochCurve {
+	
+    public static void main(String[] aArgs) throws IOException {    	
+    	List<Point> points = initialEquilateralTriangle();
+    	for ( int i = 1; i < 5; i++ ) {
+    		points = nextIteration(points);
+    	}    	
+    	
+    	String text = kochCurveText(points, IMAGE_SIZE);
+    	Files.write(Paths.get("C:/Users/psnow/Desktop/koch.svg"), text.getBytes());
+    }
+
+    private static List<Point> initialEquilateralTriangle() {
+    	final int margin = 50;
+    	final int boxSize = IMAGE_SIZE - margin;
+    	final int sideLength = Math.round(boxSize * SIN_60_DEGREES);
+    	final int x = ( boxSize + margin - sideLength ) / 2;
+    	final int y = Math.round(( boxSize + margin ) / 2 - sideLength * SIN_60_DEGREES / 3);
+    	
+    	List<Point> points = Arrays.asList(
+                new Point(x, y),
+                new Point(x + sideLength / 2, Math.round(y + sideLength * SIN_60_DEGREES)),
+                new Point(x + sideLength, y),
+                new Point(x, y)
+            );
+    	
+    	return points;    	
+    }
+
+    private static List<Point> nextIteration(List<Point> aPoints) {
+        List<Point> result = new ArrayList<Point>();
+
+        for ( int i = 0; i < aPoints.size() - 1; i++ ) {
+        	final int x0 = aPoints.get(i).x;
+            final int y0 = aPoints.get(i).y;
+            final int x1 = aPoints.get(i + 1).x;
+            final int y1 = aPoints.get(i + 1).y;
+            final int dy = y1 - y0;
+            final int dx = x1 - x0;
+
+            result.add(aPoints.get(i));
+            result.add( new Point(x0 + dx / 3, y0 + dy / 3) );
+            result.add( new Point(Math.round(x0 + dx / 2 - dy * SIN_60_DEGREES / 3),
+            					  Math.round(y0 + dy / 2 + dx * SIN_60_DEGREES / 3)) );
+            result.add( new Point(x0 + 2 * dx / 3, y0 + 2 * dy / 3) ) ;
+        }
+
+        result.add(aPoints.get(aPoints.size() - 1));
+        return result;
+    }
+
+    private static String kochCurveText(List<Point> aPoints, int aSize) {
+    	StringBuilder text = new StringBuilder();
+        text.append("<svg xmlns='http://www.w3.org/2000/svg'");
+        text.append(" width='" + aSize + "' height='" + aSize + "'>\n");
+        text.append("<rect style='width:100%;height:100%;fill:cyan'/>\n");
+        text.append("<polygon points='");
+        for ( int i = 0; i < aPoints.size(); i++ ) {
+            text.append(aPoints.get(i).x + ", " + aPoints.get(i).y + " ");
+        }
+        text.append("' style='fill:pink;stroke:black;stroke-width:2'/>\n</svg>\n");
+
+        return text.toString();
+    }
+
+    private static final int IMAGE_SIZE = 700;
+    private static final float SIN_60_DEGREES = (float) Math.sin(Math.PI / 3.0);
+
+}