BarChart.java

package com.github.mikephil.charting.charts;

import android.content.Context;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.util.Log;

import com.github.mikephil.charting.components.YAxis.AxisDependency;
import com.github.mikephil.charting.data.BarData;
import com.github.mikephil.charting.data.BarDataSet;
import com.github.mikephil.charting.data.BarEntry;
import com.github.mikephil.charting.data.DataSet;
import com.github.mikephil.charting.data.Entry;
import com.github.mikephil.charting.interfaces.BarDataProvider;
import com.github.mikephil.charting.renderer.BarChartRenderer;
import com.github.mikephil.charting.renderer.XAxisRendererBarChart;
import com.github.mikephil.charting.utils.Highlight;

/**
 * Chart that draws bars.
 * 
 * @author Philipp Jahoda
 */
public class BarChart extends BarLineChartBase<BarData> implements BarDataProvider {

    /** flag that enables or disables the highlighting arrow */
    private boolean mDrawHighlightArrow = false;

    /**
     * if set to true, all values are drawn above their bars, instead of below
     * their top
     */
    private boolean mDrawValueAboveBar = true;

    /**
     * if set to true, all values of a stack are drawn individually, and not
     * just their sum
     */
    private boolean mDrawValuesForWholeStack = true;

    /**
     * if set to true, a grey area is drawn behind each bar that indicates the
     * maximum value
     */
    private boolean mDrawBarShadow = false;

    public BarChart(Context context) {
        super(context);
    }

    public BarChart(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public BarChart(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    protected void init() {
        super.init();

        mRenderer = new BarChartRenderer(this, mAnimator, mViewPortHandler);
        mXAxisRenderer = new XAxisRendererBarChart(mViewPortHandler, mXAxis, mLeftAxisTransformer,
                this);

        mXChartMin = -0.5f;
    }

    @Override
    protected void calcMinMax() {
        super.calcMinMax();

        // increase deltax by 1 because the bars have a width of 1
        mDeltaX += 0.5f;

        // extend xDelta to make space for multiple datasets (if ther are one)
        mDeltaX *= mData.getDataSetCount();

        int maxEntry = 0;

        for (int i = 0; i < mData.getDataSetCount(); i++) {

            DataSet<? extends Entry> set = mData.getDataSetByIndex(i);

            if (maxEntry < set.getEntryCount())
                maxEntry = set.getEntryCount();
        }

        float groupSpace = mData.getGroupSpace();
        mDeltaX += maxEntry * groupSpace;
        mXChartMax = mDeltaX - mXChartMin;
    }

    /**
     * Returns the Highlight object (contains x-index and DataSet index) of the
     * selected value at the given touch point inside the BarChart.
     * 
     * @param x
     * @param y
     * @return
     */
    @Override
    public Highlight getHighlightByTouchPoint(float x, float y) {

        if (mDataNotSet || mData == null) {
            Log.e(LOG_TAG, "Can't select by touch. No data set.");
            return null;
        }

        // create an array of the touch-point
        float[] pts = new float[2];
        pts[0] = x;
        pts[1] = y;

        mLeftAxisTransformer.pixelsToValue(pts);

        if (pts[0] < mXChartMin || pts[0] > mXChartMax)
            return null;

        return getHighlight(pts[0], pts[1]);
    }

    /**
     * Returns the correct Highlight object (including xIndex and dataSet-index)
     * for the specified touch position.
     * 
     * @param xPosition
     * @return
     */
    protected Highlight getHighlight(double xPosition, double yPosition) {

        int setCount = mData.getDataSetCount();
        int valCount = mData.getXValCount();
        int dataSetIndex = 0;
        int xIndex = 0;

        // only one dataset exists
        if (!mData.isGrouped()) {

            xIndex = (int) Math.round(xPosition);

            // check bounds
            if (xIndex < 0) {
                xIndex = 0;
            } else if (xIndex >= valCount) {
                xIndex = valCount - 1;
            }

            // if this bardata is grouped into more datasets
        } else {

            // calculate how often the group-space appears
            int steps = (int) ((float) xPosition / ((float) setCount + mData.getGroupSpace()));

            float groupSpaceSum = mData.getGroupSpace() * (float) steps;

            float baseNoSpace = (float) xPosition - groupSpaceSum;

            if (mLogEnabled)
                Log.i(LOG_TAG, "base: " + xPosition + ", steps: " + steps + ", groupSpaceSum: "
                        + groupSpaceSum
                        + ", baseNoSpace: " + baseNoSpace);

            dataSetIndex = (int) baseNoSpace % setCount;
            xIndex = (int) baseNoSpace / setCount;

            if (mLogEnabled)
                Log.i(LOG_TAG, "xIndex: " + xIndex + ", dataSet: " + dataSetIndex);

            // check bounds
            if (xIndex < 0) {
                xIndex = 0;
                dataSetIndex = 0;
            } else if (xIndex >= valCount) {
                xIndex = valCount - 1;
                dataSetIndex = setCount - 1;
            }

            // check bounds
            if (dataSetIndex < 0)
                dataSetIndex = 0;
            else if (dataSetIndex >= setCount)
                dataSetIndex = setCount - 1;
        }
        
        if (!mData.getDataSetByIndex(dataSetIndex).isStacked())
            return new Highlight(xIndex, dataSetIndex);
        else
            return getStackedHighlight(xIndex, dataSetIndex, yPosition);
    }

    /**
     * This method creates the Highlight object that also indicates which value
     * of a stacked BarEntry has been selected.
     * 
     * @param xIndex
     * @param dataSet
     * @param yValue
     * @return
     */
    protected Highlight getStackedHighlight(int xIndex, int dataSet, double yValue) {

        BarEntry entry = mData.getDataSetByIndex(dataSet).getEntryForXIndex(xIndex);

        if (entry != null) {
            int stackIndex = entry.getClosestIndexAbove((float) yValue);
            Highlight h = new Highlight(xIndex, dataSet, stackIndex);
            return h;
        } else
            return null;
    }

    /**
     * Returns the bounding box of the specified Entry in the specified DataSet.
     * Returns null if the Entry could not be found in the charts data.
     * 
     * @param e
     * @return
     */
    public RectF getBarBounds(BarEntry e) {

        BarDataSet set = mData.getDataSetForEntry(e);

        if (set == null)
            return null;

        float barspace = set.getBarSpace();
        float y = e.getVal();
        float x = e.getXIndex();

        float barWidth = 0.5f;

        float spaceHalf = barspace / 2f;
        float left = x - barWidth + spaceHalf;
        float right = x + barWidth - spaceHalf;
        float top = y >= 0 ? y : 0;
        float bottom = y <= 0 ? y : 0;

        RectF bounds = new RectF(left, top, right, bottom);

        getTransformer(set.getAxisDependency()).rectValueToPixel(bounds);

        return bounds;
    }

    /**
     * set this to true to draw the highlightning arrow
     * 
     * @param enabled
     */
    public void setDrawHighlightArrow(boolean enabled) {
        mDrawHighlightArrow = enabled;
    }

    /**
     * returns true if drawing the highlighting arrow is enabled, false if not
     * 
     * @return
     */
    public boolean isDrawHighlightArrowEnabled() {
        return mDrawHighlightArrow;
    }

    /**
     * If set to true, all values are drawn above their bars, instead of below
     * their top.
     * 
     * @param enabled
     */
    public void setDrawValueAboveBar(boolean enabled) {
        mDrawValueAboveBar = enabled;
    }

    /**
     * returns true if drawing values above bars is enabled, false if not
     * 
     * @return
     */
    public boolean isDrawValueAboveBarEnabled() {
        return mDrawValueAboveBar;
    }

    /**
     * if set to true, all values of a stack are drawn individually, and not
     * just their sum
     * 
     * @param enabled
     */
    public void setDrawValuesForWholeStack(boolean enabled) {
        mDrawValuesForWholeStack = enabled;
    }

    /**
     * returns true if all values of a stack are drawn, and not just their sum
     * 
     * @return
     */
    public boolean isDrawValuesForWholeStackEnabled() {
        return mDrawValuesForWholeStack;
    }

    /**
     * If set to true, a grey area is drawn behind each bar that indicates the
     * maximum value. Enabling his will reduce performance by about 50%.
     * 
     * @param enabled
     */
    public void setDrawBarShadow(boolean enabled) {
        mDrawBarShadow = enabled;
    }

    /**
     * returns true if drawing shadows (maxvalue) for each bar is enabled, false
     * if not
     * 
     * @return
     */
    public boolean isDrawBarShadowEnabled() {
        return mDrawBarShadow;
    }

    @Override
    public BarData getBarData() {
        return mData;
    }
    
    /**
     * Returns the lowest x-index (value on the x-axis) that is still visible on
     * the chart.
     * 
     * @return
     */
    @Override
    public int getLowestVisibleXIndex() {
        
        float step = mData.getDataSetCount();
        float div = (step <= 1) ? 1 : step + mData.getGroupSpace();
        
        float[] pts = new float[] {
                mViewPortHandler.contentLeft(), mViewPortHandler.contentBottom()
        };
        
        getTransformer(AxisDependency.LEFT).pixelsToValue(pts);
        return (int) ((pts[0] <= getXChartMin()) ? 0 : (pts[0] / div) + 1);
    }

    /**
     * Returns the highest x-index (value on the x-axis) that is still visible
     * on the chart.
     * 
     * @return
     */
    @Override
    public int getHighestVisibleXIndex() {
        
        float step = mData.getDataSetCount();
        float div = (step <= 1) ? 1 : step + mData.getGroupSpace();
        
        float[] pts = new float[] {
                mViewPortHandler.contentRight(), mViewPortHandler.contentBottom()
        };
        
        getTransformer(AxisDependency.LEFT).pixelsToValue(pts);
        return (int) ((pts[0] >= getXChartMax()) ? getXChartMax() / div : (pts[0] / div));
    }
}