minor tweaks

ChrisMayfield · ChrisMayfield · commit 1d320f6bc977 · 2019-09-03T09:30:04.000-04:00
diff --git a/ch15/RegularPolygon.java b/ch15/RegularPolygon.java
@@ -45,7 +45,7 @@ public RegularPolygon(int nsides, int length) {
     public RegularPolygon(int nsides, int length, Color color) {
 
         // validate and store arguments
-        if (nsides < 3 || nsides >= 10) {
+        if (nsides < 3) {
             throw new IllegalArgumentException("invalid nsides");
         }
         if (length < 1) {
@@ -61,8 +61,8 @@ public RegularPolygon(int nsides, int length, Color color) {
         this.ypoints = new int[nsides];
         this.color = color;
 
-        // radius of the polygon (distance from origin to vertex)
-        double radius = length / (2.0 * Math.sin(Math.PI / nsides));
+        // radius of the polygon (distance from center to vertex)
+        double radius = 0.5 * length / Math.sin(Math.PI / nsides);
 
         // the angle (in radians) at each vertex
         double angle = 2.0 * Math.PI / nsides;
@@ -82,7 +82,12 @@ public RegularPolygon(int nsides, int length, Color color) {
     @Override
     public String toString() {
         StringBuilder str = new StringBuilder();
-        str.append(NAMES[npoints]);
+        if (npoints < NAMES.length) {
+            str.append(NAMES[npoints]);
+        } else {
+            str.append("Polygon");
+        }
+        // append the list of vertexes
         str.append('[');
         for (int i = 0; i < npoints; i++) {
             if (i > 0) {
diff --git a/ch15/Sim1.java b/ch15/Sim1.java
@@ -16,7 +16,7 @@ public static void main(String[] args) {
         // create some regular polygons
         RegularPolygon p3 = new RegularPolygon(3, 100, Color.GREEN);
         RegularPolygon p4 = new RegularPolygon(4, 100, Color.ORANGE);
-        RegularPolygon p5 = new RegularPolygon(5, 100, Color.MAGENTA);
+        RegularPolygon p5 = new RegularPolygon(360, 1, Color.MAGENTA);
 
         // move them out of the corner
         p3.translate(100, 100);
diff --git a/ch15/Sim2.java b/ch15/Sim2.java
@@ -1,3 +1,4 @@
+import java.awt.Toolkit;
 import javax.swing.JFrame;
 
 /**
@@ -34,6 +35,7 @@ public static void main(String[] args) {
         frame.setVisible(true);
 
         // main simulation loop
+        Toolkit toolkit = frame.getToolkit();
         while (true) {
 
             // update the drawing
@@ -43,7 +45,7 @@ public static void main(String[] args) {
             // delay the simulation
             try {
                 Thread.sleep(1000 / 60);
-                frame.getToolkit().sync();
+                toolkit.sync();
             } catch (InterruptedException e) {
                 // do nothing
             }
diff --git a/ch15/Sim3.java b/ch15/Sim3.java
@@ -1,6 +1,6 @@
+import java.awt.Toolkit;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
-
 import javax.swing.JFrame;
 import javax.swing.Timer;
 
@@ -10,7 +10,7 @@
 public class Sim3 implements ActionListener {
 
     private Drawing drawing;
-    private JFrame frame;
+    private Toolkit toolkit;
 
     /**
      * Set up the drawing and window frame.
@@ -30,12 +30,13 @@ public Sim3() {
         drawing.add(rp);
 
         // set up the window frame
-        frame = new JFrame("Drawing");
+        JFrame frame = new JFrame("Drawing");
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setResizable(false);
         frame.add(drawing);
         frame.pack();
         frame.setVisible(true);
+        toolkit = frame.getToolkit();
     }
 
     /**
@@ -53,7 +54,7 @@ public static void main(String[] args) {
     public void actionPerformed(ActionEvent e) {
         drawing.nextact();
         drawing.repaint();
-        frame.getToolkit().sync();
+        toolkit.sync();
     }
 
 }
