BubbleChart.java

/**
 * 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.chart;

import org.achartengine.model.XYMultipleSeriesDataset;
import org.achartengine.model.XYValueSeries;
import org.achartengine.renderer.SimpleSeriesRenderer;
import org.achartengine.renderer.XYMultipleSeriesRenderer;
import org.achartengine.renderer.XYSeriesRenderer;

import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.RectF;

/**
 * The bubble chart rendering class.
 */
public class BubbleChart extends XYChart {
  /** The constant to identify this chart type. */
  public static final String TYPE = "Bubble";
  /** The legend shape width. */
  private static final int SHAPE_WIDTH = 10;
  /** The minimum bubble size. */
  private static final int MIN_BUBBLE_SIZE = 6;
  /** The maximum bubble size. */
  private static final int MAX_BUBBLE_SIZE = 10;

  BubbleChart() {
  }

  /**
   * Builds a new bubble chart instance.
   * 
   * @param dataset the multiple series dataset
   * @param renderer the multiple series renderer
   */
  public BubbleChart(XYMultipleSeriesDataset dataset, XYMultipleSeriesRenderer renderer) {
    super(dataset, renderer);
  }

  /**
   * The graphical representation of a series.
   * 
   * @param canvas the canvas to paint to
   * @param paint the paint to be used for drawing
   * @param points the array of points to be used for drawing the series
   * @param seriesRenderer the series renderer
   * @param yAxisValue the minimum value of the y axis
   * @param seriesIndex the index of the series currently being drawn
   */
  @Override
public void drawSeries(Canvas canvas, Paint paint, float[] points,
      SimpleSeriesRenderer seriesRenderer, float yAxisValue, int seriesIndex) {
    XYSeriesRenderer renderer = (XYSeriesRenderer) seriesRenderer;
    paint.setColor(renderer.getColor());
    paint.setStyle(Style.FILL);
    int length = points.length;
    XYValueSeries series = (XYValueSeries) mDataset.getSeriesAt(seriesIndex);
    double max = series.getMaxValue();

    double coef = 1;
    if(max != 1)
    	coef = (MAX_BUBBLE_SIZE - MIN_BUBBLE_SIZE) / (max - 1);
    for (int i = 0; i < length; i += 2) {
    	double value = series.getValue(i / 2);
    	double size =0;
    	if(value > 0)
    		size = (value -1) * coef + MIN_BUBBLE_SIZE;
    	drawCircle(canvas, paint, points[i], points[i + 1], (float) size);
    }
  }

  @Override
  protected RectF[] clickableAreasForPoints(float[] points, float yAxisValue, int seriesIndex) {
    int length = points.length;
    XYValueSeries series = (XYValueSeries) mDataset.getSeriesAt(seriesIndex);
    double max = series.getMaxValue();
    double coef = (max > MAX_BUBBLE_SIZE) ? max / MAX_BUBBLE_SIZE : 1;
    RectF[] ret = new RectF[length / 2];
    for (int i = 0; i < length; i += 2) {
      double size = series.getValue(i / 2) * coef;
      if(size != 0)
    	  size += MIN_BUBBLE_SIZE;
      ret[i / 2] = new RectF(points[i] - (float) size, points[i + 1] - (float) size, points[i]
          + (float) size, points[i + 1] + (float) size);
    }
    return ret;
  }

  /**
   * Returns the legend shape width.
   * 
   * @param seriesIndex the series index
   * @return the legend shape width
   */
  @Override
public int getLegendShapeWidth(int seriesIndex) {
    return SHAPE_WIDTH;
  }

  /**
   * The graphical representation of the legend shape.
   * 
   * @param canvas the canvas to paint to
   * @param renderer the series renderer
   * @param x the x value of the point the shape should be drawn at
   * @param y the y value of the point the shape should be drawn at
   * @param seriesIndex the series index
   * @param paint the paint to be used for drawing
   */
  @Override
public void drawLegendShape(Canvas canvas, SimpleSeriesRenderer renderer, float x, float y,
      int seriesIndex, Paint paint) {
    paint.setStyle(Style.FILL);
    drawCircle(canvas, paint, x + SHAPE_WIDTH, y, 3);
  }

  /**
   * The graphical representation of a circle point shape.
   * 
   * @param canvas the canvas to paint to
   * @param paint the paint to be used for drawing
   * @param x the x value of the point the shape should be drawn at
   * @param y the y value of the point the shape should be drawn at
   * @param radius the bubble radius
   */
  private void drawCircle(Canvas canvas, Paint paint, float x, float y, float radius) {
    canvas.drawCircle(x, y, radius, paint);
  }

  /**
   * Returns the chart type identifier.
   * 
   * @return the chart type
   */
  @Override
public String getChartType() {
    return TYPE;
  }

}