LayerLayout.java

/**
 * LayerLayout
 * Abstract Class for new stacked graph layout algorithms
 *
 * Note: you do not need to worry about scaling to screen dimensions.
 * The display applet will do that automatically for you.
 *
 * @author Lee Byron
 * @author Martin Wattenberg
 */
public abstract class LayerLayout {

  abstract void layout(Layer[] layers);

  abstract String getName();

  /**
   * We define our stacked graphs by layers atop a baseline.
   * This method does the work of assigning the positions of each layer in an
   * ordered array of layers based on an initial baseline.
   */
  protected void stackOnBaseline(Layer[] layers, float[] baseline) {
    // Put layers on top of the baseline.
    for (int i = 0; i < layers.length; i++) {
      System.arraycopy(baseline, 0, layers[i].yBottom, 0, baseline.length);
      for (int j = 0; j < baseline.length; j++) {
        baseline[j] -= layers[i].size[j];
      }
      System.arraycopy(baseline, 0, layers[i].yTop, 0, baseline.length);
    }
  }

}