HorizontalBarChart.java

package com.github.mikephil.charting.charts;

import android.content.Context;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;

import com.github.mikephil.charting.renderer.ColumnToBarTransformer;
import com.github.mikephil.charting.utils.Utils;
import com.github.mikephil.charting.utils.YLabels;

public class HorizontalBarChart extends BarChart
{
	public HorizontalBarChart(Context context)
	{
		super(context);
	}

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

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

	@Override
	protected void init()
	{
		super.init();
		setDrawXLabels(false);
		setDrawYLabels(true);
		mTrans = new ColumnToBarTransformer();
		mValuePaint.setTextAlign(Paint.Align.LEFT);
	}

	/**
	 * Prepares a bar for drawing on the specified x-index and y-position. Also
	 * prepares the shadow-bar if enabled.
	 *
	 * @param x the x-position
	 * @param y the y-position
	 * @param barspace the space between bars
	 */
	@Override
	protected void prepareBar(float x, float y, float barspace) {

		super.prepareBar(x, y, barspace);
		float spaceHalf = barspace / 2f;

		float top = x + spaceHalf;
		float bottom = x + 1f - spaceHalf;

		mBarRect.set(0, top, y, bottom);

		mTrans.rectValueToPixel(mBarRect, mPhaseY);

		// if a shadow is drawn, prepare it too
		if (mDrawBarShadow) {
			mBarShadow.set(mBarRect.left, mOffsetTop, mBarRect.right, getHeight() - mOffsetBottom);
		}
	}
	
	@Override
	protected void calcModulus() {
	    
        float[] values = new float[9];
        mTrans.getTouchMatrix().getValues(values);

        mXLabels.mYAxisLabelModulus = (int) Math
                .ceil((mData.getXValCount() * mXLabels.mLabelHeight)
                        / (mContentRect.height() * values[Matrix.MSCALE_Y]));
	}

	@Override
	protected void drawXLabels(float yPos)
	{
		if (!mDrawXLabels) return;

		mXLabelPaint.setTextAlign(Paint.Align.RIGHT);
		// pre allocate to save performance (dont allocate in loop)
		float[] position = new float[] {
				0f, 0f
		};
		
		float offset = Utils.calcTextHeight(mXLabelPaint, mData.getXVals().get(0)) / 2f;

		int step = mData.getDataSetCount();

		for (int i = 0; i < mData.getXValCount(); i += mXLabels.mYAxisLabelModulus) {

			position[1] = i * step + i * mData.getGroupSpace()
					+ mData.getGroupSpace() / 2f;

			// center the text
			if (mXLabels.isCenterXLabelsEnabled())
				position[1] += (step / 2f);

			mTrans.pointValuesToPixel(position);

			if (position[1] >= mOffsetTop && position[1] <= getHeight() - mOffsetBottom)
			{
				String label = mData.getXVals().get(i);

				mDrawCanvas.drawText(label, mOffsetLeft-10, position[1] + offset, mXLabelPaint);
			}
		}
	}

	private static String TALL_VALUE = "100%";
	@Override
	protected float getPositiveYOffset(boolean drawAboveValueBar)
	{
		Rect bounds = new Rect();
		mValuePaint.getTextBounds(TALL_VALUE,0,TALL_VALUE.length(),bounds);

		return bounds.height()/2;
	}

	@Override
	protected float getNegativeYOffset(boolean drawAboveValueBar)
	{
		return getPositiveYOffset(drawAboveValueBar);
	}

	/**
	 * Sets up the y-axis labels. Computes the desired number of labels between
	 * the two given extremes. Unlike the papareXLabels() method, this method
	 * needs to be called upon every refresh of the view.
	 *
	 * @return
	 */
	@Override
	protected void prepareYLabels()
	{
	    mYLabels = new XLabelsAsYLabels();
//	    super.prepareYLabels();
		
	}

	private class XLabelsAsYLabels extends YLabels
	{
		/**
		 * Returns the longest formatted label (in terms of characters) the y-labels
		 * contain.
		 *
		 * @return
		 */
		@Override
		public String getLongestLabel()
		{
			String longest = "";

			for (int i = 0; i < mData.getXValCount(); i ++)
			{
				String text = mData.getXVals().get(i);

				if (longest.length() < text.length())
					longest = text;
			}

			return longest;
		}

		/**
		 * Returns the formatted y-label at the specified index. This will either
		 * use the auto-formatter or the custom formatter (if one is set).
		 *
		 * @param index
		 * @return
		 */
		@Override
		public String getFormattedLabel(int index)
		{
			super.getFormattedLabel(index);
			if (index < 0)
				return "";

			return mData.getXVals().get(index);
		}
	}
}