PieMapper.java

/**
 * Copyright (C) 2009 - 2013 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 com.codename1.charts.views;

import java.util.ArrayList;
import java.util.List;
import com.codename1.util.MathUtil;

import com.codename1.charts.models.Point;
import com.codename1.charts.models.SeriesSelection;
import com.codename1.ui.geom.Shape;

/**
 * PieChart Segment Selection Management.
 */
public class PieMapper {

  private final List<PieSegment> mPieSegmentList = new ArrayList<PieSegment>();

  private int mPieChartRadius;

  private int mCenterX, mCenterY;

  /**
   * Set PieChart location on screen.
   * 
   * @param pieRadius
   * @param centerX
   * @param centerY
   */
  public void setDimensions(int pieRadius, int centerX, int centerY) {
    mPieChartRadius = pieRadius;
    mCenterX = centerX;
    mCenterY = centerY;
  }

  /**
   * If we have all PieChart Config then there is no point in reloading it
   * 
   * @param datasetSize
   * @return true if cfg for each segment is present
   */
  public boolean areAllSegmentPresent(int datasetSize) {
    return mPieSegmentList.size() == datasetSize;
  }
  
  /**
   * Add configuration for a PieChart Segment
   * 
   * @param dataIndex
   * @param value
   * @param startAngle
   * @param angle
   */
  public void addPieSegment(int dataIndex, float value, float startAngle, float angle) {
    mPieSegmentList.add(new PieSegment(dataIndex, value, startAngle, angle));
  }
  
  /**
   * Clears the pie segments list.
   */
  public void clearPieSegments() {
    mPieSegmentList.clear();
  }

  /**
   * Fetches angle relative to pie chart center point where 3 O'Clock is 0 and
   * 12 O'Clock is 270degrees
   * 
   * @param screenPoint
   * @return angle in degress from 0-360.
   */
  public double getAngle(Point screenPoint) {
    double dx = screenPoint.getX() - mCenterX;
    // Minus to correct for coord re-mapping
    double dy = -(screenPoint.getY() - mCenterY);

    double inRads = com.codename1.util.MathUtil.atan2(dy, dx);

    // We need to map to coord system when 0 degree is at 3 O'clock, 270 at 12
    // O'clock
    if (inRads < 0)
      inRads = Math.abs(inRads);
    else
      inRads = 2 * Math.PI - inRads;

    return Math.toDegrees(inRads);
  }

  /**
   * Checks if Point falls within PieChart
   * 
   * @param screenPoint
   * @return true if in PieChart
   */
  public boolean isOnPieChart(Point screenPoint) {
    // Using a bit of Pythagoras
    // inside circle if (x-center_x)**2 + (y-center_y)**2 <= radius**2:

    double sqValue = (MathUtil.pow(mCenterX - screenPoint.getX(), 2) + MathUtil.pow(
        mCenterY - screenPoint.getY(), 2));

    double radiusSquared = mPieChartRadius * mPieChartRadius;
    boolean isOnPieChart = sqValue <= radiusSquared;
    return isOnPieChart;
  }

  /**
   * Fetches the SeriesSelection for the PieSegment selected.
   * 
   * @param screenPoint - the user tap location
   * @return null if screen point is not in PieChart or its config if it is
   */
  public SeriesSelection getSeriesAndPointForScreenCoordinate(Point screenPoint) {
    if (isOnPieChart(screenPoint)) {
      double angleFromPieCenter = getAngle(screenPoint);

      for (PieSegment pieSeg : mPieSegmentList) {
        if (pieSeg.isInSegment(angleFromPieCenter)) {
          return new SeriesSelection(0, pieSeg.getDataIndex(), pieSeg.getValue(),
              pieSeg.getValue());
        }
      }
    }
    return null;
  }
  
  private Shape getSegmentShape(PieSegment segment){
      return segment.getShape(mCenterX, mCenterY, mPieChartRadius);
  }
  
  private PieSegment getSegment(int dataIndex){
      for ( PieSegment s : mPieSegmentList ){
          if ( dataIndex == s.getDataIndex() ){
              return s;
          }
      }
      return null;
  }
  
  public Shape getSegmentShape(int dataIndex){
      PieSegment seg = getSegment(dataIndex);
      if ( seg != null ){
          return getSegmentShape(seg);
      }
      return null;
  }
  
  
}