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Semester 1/Programming 1/Java/examples/picture/Picture.java

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+
+/**
+ * This class represents a simple picture. You can draw the picture using
+ * the draw method. But wait, there's more: being an electronic picture, it
+ * can be changed. You can set it to black-and-white display and back to
+ * colors (only after it's been drawn, of course).
+ *
+ * This class was written as an early example for teaching Java with BlueJ.
+ * 
+ * @author	Michael Kolling and David J. Barnes
+ * @version 1.1  (24 May 2001)
+ */
+public class Picture
+{
+	private Square wall;
+	private Square window;
+	private Triangle roof;
+	private	Circle sun;
+
+	/**
+	 * Constructor for objects of class Picture
+	 */
+	public Picture()
+	{
+		// nothing to do... instance variables are automatically set to null
+	}
+
+	/**
+	 * Draw this picture.
+	 */
+	public void draw()
+	{
+		wall = new Square();
+		wall.moveVertical(80);
+		wall.changeSize(100);
+		wall.makeVisible();
+		
+		window = new Square();
+		window.changeColor("black");
+		window.moveHorizontal(20);
+		window.moveVertical(100);
+		window.makeVisible();
+
+		roof = new Triangle();	
+		roof.changeSize(50, 140);
+		roof.moveHorizontal(60);
+		roof.moveVertical(70);
+		roof.makeVisible();
+
+		sun = new Circle();
+		sun.changeColor("yellow");
+		sun.moveHorizontal(180);
+		sun.moveVertical(-10);
+		sun.changeSize(60);
+		sun.makeVisible();
+	}
+
+	/**
+	 * Change this picture to black/white display
+	 */
+	public void setBlackAndWhite()
+	{
+		if(wall != null)   // only if it's painted already...
+		{
+			wall.changeColor("black");
+			window.changeColor("white");
+			roof.changeColor("black");
+			sun.changeColor("black");
+		}
+	}
+
+	/**
+	 * Change this picture to use color display
+	 */
+	public void setColor()
+	{
+		if(wall != null)   // only if it's painted already...
+		{
+			wall.changeColor("red");
+			window.changeColor("black");
+			roof.changeColor("green");
+			sun.changeColor("yellow");
+		}
+	}
+
+}