ImageScrollModel.java

package games.strategy.ui;

import java.awt.Dimension;
import java.util.Observable;

/**
 * Model for an ImageScroller. Generally one large view and one small view will be
 * connected to the same model.
 *
 * <p>
 * notifies its observers when changes occur.
 * </p>
 */
public class ImageScrollModel extends Observable {
  private int m_x;
  private int m_y;
  private int m_boxWidth = 5;
  private int m_boxHeight = 5;
  private int m_maxWidth;
  private int m_maxHeight;
  private boolean m_scrollX;
  private boolean m_scrollY;

  public void setMaxBounds(final int maxWidth, final int maxHeight) {
    m_maxWidth = maxWidth;
    m_maxHeight = maxHeight;
    enforceBounds();
    updateListeners();
  }

  public void setMaxBounds(final Dimension mapDimensions) {
    setMaxBounds(mapDimensions.width, mapDimensions.height);
  }

  public void setBoxDimensions(final int maxX, final int maxy) {
    m_boxWidth = maxX;
    m_boxHeight = maxy;
    enforceBounds();
    updateListeners();
  }

  private void updateListeners() {
    super.setChanged();
    super.notifyObservers();
  }

  public void setScrollX(final boolean aBool) {
    m_scrollX = aBool;
    enforceBounds();
    updateListeners();
  }

  public void setScrollY(final boolean aBool) {
    m_scrollY = aBool;
    enforceBounds();
    updateListeners();
  }

  private void enforceBounds() {
    if (!m_scrollY) {
      if (m_y < 0) {
        m_y = 0;
      }
      if (m_y + m_boxHeight > m_maxHeight) {
        m_y = m_maxHeight - m_boxHeight;
      }
    } else {
      // don't let the map scroll infinitely,
      // when it gets to be twice the height to the up or down, move it back one length
      while (m_y > m_maxHeight) {
        m_y -= m_maxHeight;
      }
      while (m_y < -m_maxHeight) {
        m_y += m_maxHeight;
      }
    }
    // if the box is bigger than the map
    // put us at 0,0
    if (m_boxHeight > m_maxHeight) {
      m_y = 0;
    }
    if (!m_scrollX) {
      if (m_x < 0) {
        m_x = 0;
      }
      if (m_x + m_boxWidth > m_maxWidth) {
        m_x = m_maxWidth - m_boxWidth;
      }
    } else {
      // don't let the map scroll infinitely,
      // when it gets to be twice the length to the left or right, move it back one length
      while (m_x > m_maxWidth) {
        m_x -= m_maxWidth;
      }
      while (m_x < -m_maxWidth) {
        m_x += m_maxWidth;
      }
    }
    // if the box is bigger than the map
    // put us at 0,0
    if (m_boxWidth > m_maxWidth) {
      m_x = 0;
    }
  }

  public boolean getScrollX() {
    return m_scrollX;
  }

  public int getX() {
    return m_x;
  }

  public int getY() {
    return m_y;
  }

  public int getBoxWidth() {
    return m_boxWidth;
  }

  public int getBoxHeight() {
    return m_boxHeight;
  }

  public int getMaxWidth() {
    return m_maxWidth;
  }

  public int getMaxHeight() {
    return m_maxHeight;
  }

  public void set(final int x, final int y) {
    m_x = x;
    m_y = y;
    enforceBounds();
    updateListeners();
  }
}