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Semester 1/Programming 1/Java/examples/projects/chapter06/scribble/DrawDemo.java

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+import java.awt.Color;
+import java.util.Random;
+
+/**
+ * Class DrawDemo - provides some short demonstrations showing how to use the 
+ * Pen class to create various drawings.
+ *
+ * @author Michael Kölling and David J. Barnes
+ * @version 2016.02.29
+ */
+
+public class DrawDemo
+{
+    private Canvas myCanvas;
+    private Random random;
+
+    /**
+     * Prepare the drawing demo. Create a fresh canvas and make it visible.
+     */
+    public DrawDemo()
+    {
+        myCanvas = new Canvas("Drawing Demo", 500, 400);
+        random = new Random();
+    }
+
+    /**
+     * Draw a square on the screen.
+     */
+    public void drawSquare()
+    {
+        Pen pen = new Pen(320, 260, myCanvas);
+        pen.setColor(Color.BLUE);
+
+        square(pen);
+    }
+
+    /**
+     * Draw a wheel made of many squares.
+     */
+    public void drawWheel()
+    {
+        Pen pen = new Pen(250, 200, myCanvas);
+        pen.setColor(Color.RED);
+
+        for (int i=0; i<36; i++) {
+            square(pen);
+            pen.turn(10);
+        }
+    }
+
+    /**
+     * Draw a square in the pen's color at the pen's location.
+     */
+    private void square(Pen pen)
+    {
+        for (int i=0; i<4; i++) {
+            pen.move(100);
+            pen.turn(90);
+        }
+    }
+
+    /**
+     * Draw some random squiggles on the screen, in random colors.
+     */
+    public void colorScribble()
+    {
+        Pen pen = new Pen(250, 200, myCanvas);
+
+        for (int i=0; i<10; i++) {
+            // pick a random color
+            int red = random.nextInt(256);
+            int green = random.nextInt(256);
+            int blue = random.nextInt(256);
+            pen.setColor(new Color(red, green, blue));
+            
+            pen.randomSquiggle();
+        }
+    }
+    
+    /**
+     * Clear the screen.
+     */
+    public void clear()
+    {
+        myCanvas.erase();
+    }
+}