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This tutorial will briefly look at programming with the Generation5 JDK. The Generation5 JDK is broad and covers a wide-range of material, so this tutorial will focus on create a customized cellular automata renderer to create Conway's Life diagrams (see below). A separate tutorial will look at creating your own cellular automata examples.

For writeImage we can use ImageHelper's writeVisualizedImage method (org.generation5.util package) that takes the same parameters as writeImage with an additional parameter, an instance of Visualizable. The method then uses the render method to draw onto a graphics context, then saves that graphics context to a file:

  //
  // String filename
  // int width
  // int height
  // Visualizable content
  //
  BufferedImage buffer = new BufferedImage(width, height, 1);
  Graphics2D graphics = buffer.createGraphics();
        
  content.render(graphics, width, height);

  File file = new File(filename);
  ImageIO.write(buffer, "png", file);

Understanding the Problem

We will be creating a class called CellDiagram to solve this problem. Since we will be wanting to write the diagrams, the class has to implement Visualizable as discussed.

Rendering the Cells

public class CellDiagram implements Visualizable {
    public void render(java.awt.Graphics graphics, int pw, int ph) {
        // Diagram implementation here
    }

    public void writeImage(String s, int width, int height) {
        try {
            ImageHelper.writeVisualizedImage(s, width, height, this);
        } catch (IOException e) {
            System.err.println(e);
        }
    }

    public static class CellLife extends ConwaysLifeCA {
        public void render(java.awt.Graphics graphics, int pw, int ph) {
            // Cell implementation here
        }
    }
}

Rendering Multiple Instances

Next, we render the various steps on buffered images, advancing the CA one time-step by called ca.doStep. Finally, we copy the images on to the final graphics context using drawImage and then drawing a border. To expand the usefulness of the class further, we will allow the images to be drawn across multiple rows and columns.

BufferedImage[] shots = new BufferedImage[steps];
int dw = ca.getSizeX() * ca.getCASize() + 
        (ca.getSizeX() - 1) * ca.cellSpace;
int dy = ca.getSizeY() * ca.getCASize() +
        (ca.getSizeY() - 1) * ca.cellSpace;

dw += borderSize; dy += borderSize;

for (int i=0; i<shots.length; i++)
    shots[i] = new BufferedImage(dw, dy, 1);

for (int i=0; i<shots.length; i++) {
    ca.render(shots[i].getGraphics(), dw, dy);
    ca.doStep();
}
        
g.setColor(ca.getBackgroundColor());
g.fillRect(0, 0,  width, height);
for (int i=0; i<shots.length; i++)
    g.drawImage(shots[i], (dw) * (i % columns), 
                          (dy) * (i / columns), dw, dy, null);
g.setColor(java.awt.Color.BLACK);
g.drawRect(0, 0, width-1, height-1);

Using the Class

Now for some examples of how to use the class:

Glider - Type 1

ca.setBackgroundColor(java.awt.Color.lightGray);
ca.setWorldSize(6, 6);
ca.setWorldAtEx(1, 1, "0,0,1;1,0,1;0,1,1");
ca.init();
        
diagram.writeImage("glider01.png", diagram.getDiagramWidth(),
                                   diagram.getDiagramHeight());

Glider - Type 2

diagram.setDimensions(2,3);
ca.setWorldSize(9, 7);
ca.setWorldAtEx(1, 2, "0,0,1,1;1,1,0,1,1;1,1,1,1;0,1,1");
ca.init();

diagram.writeImage("glider02.png", diagram.getDiagramWidth(),
                                   diagram.getDiagramHeight());

Static Object

diagram.setDimensions(2,2);
diagram.setSteps(4);
ca.setWorldSize(17, 17);
ca.setWorldAtEx(2, 2, "0,0,1,1,1;0;1,0,0,0,0,1;" + 
                      "1,0,0,0,0,1;1,0,0,0,0,1;0,0,1,1,1;");
ca.setWorldAtEx(9, 2, "0,1,1,1;0;1,0,0,0,0,1;" + 
                      "1,0,0,0,0,1;1,0,0,0,0,1;0,1,1,1;");
ca.setWorldAtEx(2, 9, "0,0,1,1,1;1,0,0,0,0,1;" + 
                      "1,0,0,0,0,1;1,0,0,0,0,1;0;0,0,1,1,1;");
ca.setWorldAtEx(9, 9, "0,1,1,1;1,0,0,0,0,1;1,0,0,0,0,1;" +
                      "1,0,0,0,0,1;0;0,1,1,1;");
ca.setBackgroundColor(java.awt.Color.WHITE);
ca.setCASize(8);
ca.init();
diagram.writeImage("static01.png", diagram.getDiagramWidth(),
                                   diagram.getDiagramHeight());

Future Improvements

CellDiagram.java