Pan.java :  » Chart » achartengine » org » achartengine » tools » Android Open Source

/**
 * Copyright (C) 2009, 2010 SC 4ViewSoft SRL
 *  
 * 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.achartengine.tools;

import org.achartengine.chart.XYChart;

import android.graphics.PointF;

/**
 * The pan tool.
 */
public class Pan extends AbstractTool {

  /**
   * Builds and instance of the pan tool.
   * 
   * @param chart the XY chart
   */
  public Pan(XYChart chart) {
    super(chart);
  }

  /**
   * Apply the tool.
   * 
   * @param oldX the previous location on X axis
   * @param oldY the previous location on Y axis
   * @param newX the current location on X axis
   * @param newY the current location on the Y axis
   */
  public void apply(float oldX, float oldY, float newX, float newY) {
    double[] range = getRange();
    double[] limits = mRenderer.getPanLimits();
    boolean limited = limits != null && limits.length == 4;
    double[] calcRange = mChart.getCalcRange();
    if (range[0] == range[1] && calcRange[0] == calcRange[1] || range[2] == range[3]
        && calcRange[2] == calcRange[3]) {
      return;
    }
    checkRange(range);

    PointF realPoint = mChart.toRealPoint(oldX, oldY);
    PointF realPoint2 = mChart.toRealPoint(newX, newY);
    double deltaX = realPoint.x - realPoint2.x;
    double deltaY = realPoint.y - realPoint2.y;
    if (mRenderer.isPanXEnabled()) {
      if (limited) {
        if (limits[0] > range[0] + deltaX) {
          setXRange(limits[0], limits[0] + (range[1] - range[0]));
        } else if (limits[1] < range[1] + deltaX) {
          setXRange(limits[1] - (range[1] - range[0]), limits[1]);
        } else {
          setXRange(range[0] + deltaX, range[1] + deltaX);
        }
      } else {
        setXRange(range[0] + deltaX, range[1] + deltaX);
      }
    }
    if (mRenderer.isPanYEnabled()) {
      if (limited) {
        if (limits[2] > range[2] + deltaY) {
          setYRange(limits[2], limits[2] + (range[3] - range[2]));
        } else if (limits[3] < range[3] + deltaY) {
          setYRange(limits[3] - (range[3] - range[2]), limits[3]);
        } else {
          setYRange(range[2] + deltaY, range[3] + deltaY);
        }
      } else {
        setYRange(range[2] + deltaY, range[3] + deltaY);
      }
    }
  }
}