scale.java

基于JXTA开发平台的下载软件开发源代码

/*
 * File    : Scale.java
 * Created : 15 d閏. 2003}
 * By      : Olivier
 *
 * Azureus - a Java Bittorrent client
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details ( see the LICENSE file ).
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package org.gudy.azureus2.ui.swt.components.graphics;

/**
 * @author Olivier
 *
 */
public class Scale {
  
  //The target number of pixels per scale level
  private int pixelsPerLevel = 50;
      
  //The max value
  private int max = 1;
  
  //The displayed number of levels
  private int nbLevels;
  
  //The computed (dislayed max)
  private int displayedMax;
  
  
  //The number of pixels
  private int nbPixels = 1;
  
  int scaleFactor;
  int powFactor;
  
  public void setMax(int max) {
    this.max = max;  
    if(max < 1)
      max = 1;
    computeValues();
  }
  
  public int getMax() {
    return this.max;
  }
  
  public void setNbPixels(int nbPixels) {
    this.nbPixels = nbPixels;
    if(nbPixels < 1)
      nbPixels = 1;
    computeValues();
  }
  
  private void computeValues() {
    int targetNbLevels = nbPixels / pixelsPerLevel;
    if(targetNbLevels < 1)
      targetNbLevels = 1;
    scaleFactor = max / targetNbLevels;
    powFactor = 1;
    while(scaleFactor >= 10) {
      powFactor = 10 * powFactor;
      scaleFactor = scaleFactor / 10;
    }
    if(scaleFactor >= 5)
      scaleFactor = 5;
    else if(scaleFactor >= 2)
      scaleFactor = 2;
    else
      scaleFactor = 1;
    
    nbLevels = max / (scaleFactor * powFactor) + 1;
    displayedMax = scaleFactor * powFactor * nbLevels;    
  }
  
  
  public int[] getScaleValues() {
    int[] result = new int[nbLevels+1];
    for(int i = 0 ; i < nbLevels + 1 ; i++) {
      result[i] = i * scaleFactor * powFactor;
    }
    return result;
  }
  
  public int getScaledValue(int value) {
    return (value * nbPixels) / displayedMax;
  }
  
}