Transformer.java

/*******************************************************************************
 * Copyright 2012 Pearson Education
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/
package org.semantictools.graphics;

public class Transformer {
  
  private int dx;
  private int dy;
  
  public Transformer(int dx, int dy) {
    this.dx = dx;
    this.dy = dy;
  }
  
  public Transformer(Widget w) {
    set(w);
  }
  
  /**
   * Returns the transformed x-coordinate for the point (x0, y0)
   */
  public int x(int x0, int y0) {
    return x0 + dx;
  }
  
  /**
   * Returns the transformed y-coordinate for the point (x0, y0)
   */
  public int y(int x0, int y0) {
    return y0 + dy;
  }

  /**
   * Returns the amount of translation along the x-axis
   */
  public int getDx() {
    return dx;
  }

  /**
   * Sets the amount of translation along the x-axis
   */
  public void setDx(int dx) {
    this.dx = dx;
  }

  /**
   * Returns the amount of translation along the y-axis
   */
  public int getDy() {
    return dy;
  }

  /**
   * Sets the amount of translation along the y-axis
   */
  public void setDy(int dy) {
    this.dy = dy;
  }
  
  /**
   * Increases the translation by dx along the x-axis and dy along the y-axis.
   */
  public void translate(int dx, int dy) {
    this.dx += dx;
    this.dy += dy;
  }
  
  public void push(Widget widget) {
    int dx = widget.getBounds().getLeft();
    int dy = widget.getBounds().getTop();
    translate(dx, dy);
  }
  
  public void pop(Widget widget) {

    int dx = -widget.getBounds().getLeft();
    int dy = -widget.getBounds().getTop();
    translate(dx, dy);
  }
  
  public void setTranslation(int dx, int dy) {
    this.dx = dx;
    this.dy = dy;
  }
  
  public void set(Widget widget) {
    while (widget != null) {
      push(widget);
      widget = widget.getParent();
    }
  }
  
  
  public String toString() {
    return "Transformer(dx=" + dx + ", dy=" + dy + ")";
  }
}