CS 151 - Lecture 17

Cay S. Horstmann

Lab

• Work with a buddy
• One of you codes, the other types up the answers.
• One of you submits the code in the lab17 subdirectory of your personal repo, the other submits a file report.txt in the lab17 subdirectory of your personal repo.
• Put the name of the coding buddy into the report

A Social Network Editor

• Make a copy of the ch08/graphed2 directory in the book code which you should have cloned some time ago. If you haven't recently updated your local copy, do that first.

  cd path/to/bookCode
  git pull
  cp -R ch08/graphed2 ~/network
  

  Then make an Eclipse project from existing sources with the files in ~/network.
• Use Refactor → Rename to rename SimpleGraph and SimpleGraphEditor to NetworkGraph and NetworkGraphEditor.
• Use the Ctrl+Space key to add a setSize method to CircleNode.
• Add a class PersonNode that extends CircleNode. Supply a default constructor that sets the superclass color to white and the size to 40. Add a field imageURL, and use Ctrl+Space to generate a getter and setter for it.
• In NetworkGraph, change the prototypes so you no longer have the circle nodes but instead have one PersonNode.
• Run the program. Add a person (which still looks like a circle). Select Edit → Properties. What happens? Why?
• Supply an image URL in the dialog. Here are a few (right-click to copy address):
  
  What happens? Why?

Drawing the Image

• Let's draw the image. Which method do you have to define?
• The easiest way is to make an image icon:

  public class PersonNode
  {
     public void setImageURL()
     {
        ...
        try
        {
           icon = new ImageIcon(new URL(imageURL));
        } 
        catch (IOException ex)
        {         
        }
     }
  
     private ImageIcon icon;
  }
  

• Call the paintIcon method of the ImageIcon. You'll need to find the bounds to put it in the right place. What did you do?
• Make it so that a default PersonNode isn't blank but uses a default icon such as this one:
• You should now be able to make a network with some friends and not-so-friends.
• What did you need to know in order to make this program? What did you get for free from the framework?

Extra Time?

• It would be nice if the nodes would be circular since they extend CircularNode and the line attachments are at the circle boundary. Do this:

  Shape oldClip = g2.getClip();
  g2.setClip(new Ellipse2D.Double(...));
  Paint
   g2.setClip(oldClip);

• It would be nice if one could use any image, not just one that was pre-scaled to the correct size. Replace the ImageIcon icon field with a field Image image. In setImageURL, call

  image = new ImageIcon(new URL(imageURL)).getImage();

  In the draw method, draw the image like this:

  double width = image.getWidth(null);
  double height = image.getHeight(null);
  Rectangle2D bounds = getBounds();
  double scale = Math.min(bounds.getWidth() / width, bounds.getHeight() / height);
  width = scale * width;
  height = scale * height;
  g2.drawImage(image, (int) (bounds.getX() + bounds.getWidth() - width), 
              (int) (bounds.getY() + bounds.getHeight() - height), 
              (int) width, (int) height, null);
  

  What does this code do?
• Try it out with some larger image such as this one: trump-large.jpg
• Now try to save your graph. What happens? Why?
• How do you fix it?