Sams Teach Yourself Java 2 in 24 Hours

By Rogers Cadenhead

• Table of Contents
  • Copyright
  • About the Author
  • About the Technical Editor
  • Acknowledgments
  • We Want to Hear from You!
  • Reader Services
  • Introduction
  • Hour 1. Becoming a Programmer
  • Hour 2. Writing Your First Program
  • Hour 3. Vacationing in Java
  • Hour 4. Understanding How Java Programs Work
  • Part II: Learning the Basics of Programming
  • Hour 5. Storing and Changing Information in a Program
  • Hour 6. Using Strings to Communicate
  • Hour 7. Using Conditional Tests to Make Decisions
  • Hour 8. Repeating an Action with Loops
  • Part III: Working with Information in New Ways
  • Hour 9. Storing Information with Arrays
  • Hour 10. Creating Your First Object
  • Hour 11. Describing What Your Object Is Like
  • Hour 12. Making the Most of Existing Objects
  • Part IV: Programming a Graphical User Interface
  • Hour 13. Building a Simple User Interface
  • Hour 14. Laying Out a User Interface
  • Hour 15. Responding to User Input
  • Hour 16. Building a Complex User Interface
  • Part V: Creating Multimedia Programs
  • Hour 17. Creating Interactive Web Programs
  • Hour 18. Handling Errors in a Program
  • Hour 19. Creating a Threaded Program
  • Hour 20. Reading and Writing Files
  • Part VI: Creating Multimedia Programs
  • Hour 21. Using Fonts and Color
  • Hour 22. Playing Sound Files
  • Hour 23. Working with Graphics
    • Using Graphics
    • Drawing Lines and Shapes
    • Workshop: Baking a Pie Graph
    • Summary
    • Q&A
    • Quiz
    • Activities
  • Hour 24. Creating Animation
  • Part VII: Appendixes
  • Appendix A. Tackling New Features of Java 2 Version 1.4
  • Appendix B. Using the Java 2 Software Development Kit
  • Appendix C. Programming with the Java 2 Software Development Kit
  • Appendix D. Using Sun ONE Studio
  • Appendix E. Where to Go from Here: Java Resources
  • Appendix F. This Book's Web Site

Summary

Drawing something using the polygons and other shapes available with Java might seem like more trouble than it's worth, especially when you can load image files such as .GIF files and .JPG files, as you'll see in the next hour. However, graphics depicted with polygons have two advantages over graphics that are loaded from image files:

• Speed— Even a small graphic, such as an icon, would take longer to load and display than a series of polygons.
• Scaling— You can change the size of an entire image that uses polygons simply by changing the values to create it. For example, you could add a function to the Sign class that multiplies all (x,y) points in each shape by two before they are created, and it would result in an image twice as large. Polygon images scale much more quickly than image files and produce better results.

There are many instances where it makes more sense to use graphics files in your programs, and you will be trying some of them in the next hour.

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