RangeBarChart.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.XYSeries;
import org.achartengine.renderer.SimpleSeriesRenderer;
import org.achartengine.renderer.XYMultipleSeriesRenderer;
import org.achartengine.util.MathHelper;

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

/**
 * The range bar chart rendering class.
 */
public class RangeBarChart extends BarChart {
  /** The chart type. */
  public static final String TYPE = "RangeBar";

  RangeBarChart() {
  }

  /**
   * Builds a new range bar chart instance.
   * 
   * @param dataset the multiple series dataset
   * @param renderer the multiple series renderer
   * @param type the range bar chart type
   */
  public RangeBarChart(XYMultipleSeriesDataset dataset, XYMultipleSeriesRenderer renderer, Type type) {
    super(dataset, renderer, type);
  }

  /**
   * 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
   */
  public void drawSeries(Canvas canvas, Paint paint, float[] points,
      SimpleSeriesRenderer seriesRenderer, float yAxisValue, int seriesIndex) {
    int seriesNr = mDataset.getSeriesCount();
    int length = points.length;
    paint.setColor(seriesRenderer.getColor());
    paint.setStyle(Style.FILL);
    float halfDiffX = getHalfDiffX(points, length, seriesNr);
    for (int i = 0; i < length; i += 4) {
      float xMin = points[i];
      float yMin = points[i + 1];
      // xMin = xMax
      float xMax = points[i + 2];
      float yMax = points[i + 3];
      drawBar(canvas, xMin, yMin, xMax, yMax, halfDiffX, seriesNr, seriesIndex, paint);
    }
    paint.setColor(seriesRenderer.getColor());
  }

  /**
   * The graphical representation of the series values as text.
   * 
   * @param canvas the canvas to paint to
   * @param series the series to be painted
   * @param renderer the series renderer
   * @param paint the paint to be used for drawing
   * @param points the array of points to be used for drawing the series
   * @param seriesIndex the index of the series currently being drawn
   */
  protected void drawChartValuesText(Canvas canvas, XYSeries series, SimpleSeriesRenderer renderer,
      Paint paint, float[] points, int seriesIndex) {
    int seriesNr = mDataset.getSeriesCount();
    float halfDiffX = getHalfDiffX(points, points.length, seriesNr);
    for (int i = 0; i < points.length; i += 4) {
      int index = i / 2;
      float x = points[i];
      if (mType == Type.DEFAULT) {
        x += seriesIndex * 2 * halfDiffX - (seriesNr - 1.5f) * halfDiffX;
      }

      if (series.getY(index + 1) != MathHelper.NULL_VALUE) {
        // draw the maximum value
        drawText(canvas, getLabel(series.getY(index + 1)), x,
            points[i + 3] - renderer.getChartValuesSpacing(), paint, 0);
      }
      if (series.getY(index) != MathHelper.NULL_VALUE) {
        // draw the minimum value
        drawText(canvas, getLabel(series.getY(index)), x,
            points[i + 1] + renderer.getChartValuesTextSize() + renderer.getChartValuesSpacing()
                - 3, paint, 0);
      }
    }
  }

  /**
   * Returns the value of a constant used to calculate the half-distance.
   * 
   * @return the constant value
   */
  protected float getCoeficient() {
    return 0.5f;
  }

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

}