LineGraphView.java

/**
 * This file is part of GraphView.
 *
 * GraphView is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * GraphView is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GraphView.  If not, see <http://www.gnu.org/licenses/lgpl.html>.
 *
 * Copyright Jonas Gehring
 */

package com.jjoe64.graphview;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Paint.Align;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;

import com.jjoe64.graphview.GraphViewSeries.GraphViewSeriesStyle;

/**
 * Line Graph View. This draws a line chart.
 */
public class LineGraphView extends GraphView {
	private final Paint paintBackground;
	private boolean drawBackground;
	private boolean drawDataPoints;
	private float dataPointsRadius = 10f;

	public LineGraphView(Context context, AttributeSet attrs) {
		super(context, attrs);

		paintBackground = new Paint();
		paintBackground.setColor(Color.rgb(20, 40, 60));
		paintBackground.setStrokeWidth(4);
		paintBackground.setAlpha(128);
	}

	public LineGraphView(Context context, String title) {
		super(context, title);

		paintBackground = new Paint();
		paintBackground.setColor(Color.rgb(20, 40, 60));
		paintBackground.setStrokeWidth(4);
		paintBackground.setAlpha(128);
	}

	
	@Override
	public void drawSeries(Canvas canvas, GraphViewDataInterface[] values,
			float graphwidth, float graphheight, float border, double minX,
			double minY, double diffX, double diffY, float horstart,
			GraphViewSeriesStyle style) {
		
		float colwidth = graphwidth / (values.length);

		float offset = 0;
		
		// draw background
				double lastEndY = 0;
				double lastEndX = 0;

				// draw data
				paint.setStrokeWidth(style.thickness);
				paint.setColor(style.color);

				Path bgPath = null;
				if (drawBackground) {
					bgPath = new Path();
				}

				lastEndY = 0;
				lastEndX = 0;
				float firstX = 0;
				
		// draw data
		for (int i = 0; i < values.length; i++) {
			float valY = (float) (values[i].getY() - minY);
			float ratY = (float) (valY / diffY);
			float y = graphheight * ratY;

			// hook for value dependent color
			if (style.getValueDependentColor() != null) {
				paint.setColor(style.getValueDependentColor().get(values[i]));
			} else {
				paint.setColor(style.color);
			}

			float left = (i * colwidth) + horstart - offset;
			float right = ((i * colwidth) + horstart) + (colwidth - 1) - offset;
			
			double x = (left + right)/2;

			if (i > 0) {
				float startX = (float) lastEndX;
				float startY = (float) (border - lastEndY) + graphheight;
				float endX = (float) x;
				float endY = (float) (border - y) + graphheight;

				// draw data point
				if (drawDataPoints) {
					// fix: last value was not drawn. Draw here now the end
					// values
					canvas.drawCircle(endX, endY, dataPointsRadius, paint);
				}

				canvas.drawLine(startX, startY, endX, endY, paint);
				if (bgPath != null) {
					if (i == 1) {
						firstX = startX;
						bgPath.moveTo(startX, startY);
					}
					bgPath.lineTo(endX, endY);
				}
			} else if (drawDataPoints) {
				// fix: last value not drawn as datapoint. Draw first point
				// here, and then on every step the end values (above)
				float first_X = (float) x;
				float first_Y = (float) (border - y) + graphheight;
				canvas.drawCircle(first_X, first_Y, dataPointsRadius, paint);
			}
			lastEndY = y;
			lastEndX = x;

		}

//		//draw data
//		for (int i = 0; i < values.length; i++) {
//			double valY = values[i].getY() - minY;
//			double ratY = valY / diffY;
//			double y = graphheight * ratY;
//
//			double valX = values[i].getX() - minX;
//			double ratX = valX / diffX;
//			double x = graphwidth * ratX;
//
//			if (i > 0) {
//				float startX = (float) lastEndX + (horstart + 1);
//				float startY = (float) (border - lastEndY) + graphheight;
//				float endX = (float) x + (horstart + 1);
//				float endY = (float) (border - y) + graphheight;
//
//				// draw data point
//				if (drawDataPoints) {
//					// fix: last value was not drawn. Draw here now the end
//					// values
//					canvas.drawCircle(endX, endY, dataPointsRadius, paint);
//					canvas.drawText(endX +"", endX, endY, paint);
//				}
//
//				canvas.drawLine(startX, startY, endX, endY, paint);
//				if (bgPath != null) {
//					if (i == 1) {
//						firstX = startX;
//						bgPath.moveTo(startX, startY);
//					}
//					bgPath.lineTo(endX, endY);
//				}
//			} else if (drawDataPoints) {
//				// fix: last value not drawn as datapoint. Draw first point
//				// here, and then on every step the end values (above)
//				float first_X = (float) x + (horstart + 1);
//				float first_Y = (float) (border - y) + graphheight;
//				canvas.drawCircle(first_X, first_Y, dataPointsRadius, paint);
//			}
//			lastEndY = y;
//			lastEndX = x;
//		}

		if (bgPath != null) {
			// end / close path
			bgPath.lineTo((float) lastEndX, graphheight + border);
			bgPath.lineTo(firstX, graphheight + border);
			bgPath.close();
			canvas.drawPath(bgPath, paintBackground);
		}
	}

	public int getBackgroundColor() {
		return paintBackground.getColor();
	}

	public float getDataPointsRadius() {
		return dataPointsRadius;
	}

	public boolean getDrawBackground() {
		return drawBackground;
	}

	public boolean getDrawDataPoints() {
		return drawDataPoints;
	}

	/**
	 * sets the background color for the series. This is not the background
	 * color of the whole graph.
	 * 
	 * @see #setDrawBackground(boolean)
	 */
	@Override
	public void setBackgroundColor(int color) {
		paintBackground.setColor(color);
	}

	/**
	 * sets the radius of the circles at the data points.
	 * 
	 * @see #setDrawDataPoints(boolean)
	 * @param dataPointsRadius
	 */
	public void setDataPointsRadius(float dataPointsRadius) {
		this.dataPointsRadius = dataPointsRadius;
	}

	/**
	 * @param drawBackground
	 *            true for a light blue background under the graph line
	 * @see #setBackgroundColor(int)
	 */
	public void setDrawBackground(boolean drawBackground) {
		this.drawBackground = drawBackground;
	}

	/**
	 * You can set the flag to let the GraphView draw circles at the data points
	 * 
	 * @see #setDataPointsRadius(float)
	 * @param drawDataPoints
	 */
	public void setDrawDataPoints(boolean drawDataPoints) {
		this.drawDataPoints = drawDataPoints;
	}

}