/**
 * Interface for things mapping sim coordinates to screen coordinates
 * @author     Michael Schuresko
 * @version    %I%, %G%
 * @since      1.0
 */

public interface IProjection
{

    /**
     * Finds the ith component in screen coordinates of a vector
     * indicated by the portion of the array arrLfState starting
     * at nIdxOff;
     * @param i which component of screen coordinates to get (0=x, 1=y)
     * @param arrLfState global state vector in sim coordinates
     * @param nIdxOff offset index in arrLfState of the coord we're looking
     * for
     * @return ith component in screen coordinates
     */
    public int getScreenComp(int i, double [] arrLfState, int nIdxOff);

    /**
     * Scales (possibly including rotation and flip)
     * a vector, without applying global translation
     * @param arrLfVec array containing vector to scale (transform)
     * @param nIdxOff offset of begining of vector to scale in
     * arrLfVec
     * @return integer array containing scaled vector discretized
     * to pixel differences.
     */
    public int [] scaleVector(double [] arrLfVec, int nIdxOff);

    /**
     * Simple scale function for 2d circles etc.
     */
    public int scaleRadius(double lfRad) throws Exception;

    public int width(); public int height();

    public int top(); public int left();
    
    public void scaleProjection(int nNewX, int nNewY);
    
    public void xlateProjection(int nXOff, int nYOff);
    
    public void resize(int nNewWidth, int nNewHeight);
}