Android中使用Canvas绘制南丁格尔玫瑰图(Nightingale rose diagram)

南丁格尔玫瑰图 在常规图表中实在很惊艳，但我初看没看懂，一查原来南丁格尔这么伟大，确实值得尊敬。

再仔细研究了下这种图的构成，发现原来就是把柱形图的柱形换成了扇形图的半径来表示，当然，变种有好多，我这只是说我理解的这种。

知道了其构成方式后就好实现了，依传入参数个数决定其扇形角度，依百分比决定其扇形的半径长度，然后就一切都水到渠成了。

漂亮的美图献上:

附上实现代码:

package com.xcl.chart;

/**
 * Canvas练习
 * 	 自已画南丁格尔玫瑰图(Nightingale rose diagram)
 *
 * author:xiongchuanliang
 * date:2014-4-12
 */

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.RectF;
import android.util.DisplayMetrics;
import android.view.View;

public class PanelRoseChart extends View{

	private int ScrWidth,ScrHeight;	

	 //演示用的百分比例,实际使用中，即为外部传入的比例参数
	private final float arrPer[] = new float[]{40f,50f,60f,35f,70f,80f,90f};
	//演示用标签
	private final String arrPerLabel[] = new String[]{"PostgreSQL","Sybase","DB2","国产及其它","MySQL","Ms Sql","Oracle"};
	//RGB颜色数组
	private final int arrColorRgb[][] = { {77, 83, 97},
							       {148, 159, 181},
							       {253, 180, 90},
							       {52, 194, 188},
							       {39, 51, 72},
							       {255, 135, 195},
							       {215, 124, 124}} ;

public PanelRoseChart(Context context) {
		super(context);
		// TODO Auto-generated constructor stub

		//屏幕信息
		DisplayMetrics dm = getResources().getDisplayMetrics();
		ScrHeight = dm.heightPixels;
		ScrWidth = dm.widthPixels;
	}

	public void onDraw(Canvas canvas){
		//画布背景
		canvas.drawColor(Color.BLACK);		     

    float cirX = ScrWidth / 2;
    float cirY = ScrHeight / 3 ;
    float radius = ScrHeight / 5 ;//150; 

    float arcLeft = cirX - radius;
    float arcTop = cirY - radius ;
    float arcRight = cirX + radius ;
    float arcBottom = cirY + radius ;
    RectF arcRF0 = new RectF(arcLeft ,arcTop,arcRight,arcBottom);  

    //画笔初始化
		Paint PaintArc = new Paint();
		Paint PaintLabel = new Paint();
		PaintLabel.setColor(Color.WHITE);
		PaintLabel.setTextSize(16);     

		PaintLabel.setAntiAlias(true);
		PaintArc.setAntiAlias(true);
    //位置计算类
    XChartCalc xcalc = new XChartCalc();	

    float Percentage = 0.0f;
 		float CurrPer = 0.0f;
 		float NewRaidus = 0.0f;
		int i= 0; 

		 //将百分比转换为扇形半径长度
		Percentage = 360 / arrPer.length;
		Percentage = (float)(Math.round(Percentage *100))/100; 

    for(i=0; i<arrPer.length; i++)
    {
      //将百分比转换为新扇区的半径
      NewRaidus = radius * (arrPer[i]/ 100);
      NewRaidus = (float)(Math.round(NewRaidus *100))/100; 

      float NewarcLeft = cirX - NewRaidus;
      float NewarcTop = cirY - NewRaidus ;
      float NewarcRight = cirX + NewRaidus ;
      float NewarcBottom = cirY + NewRaidus ;
      RectF NewarcRF = new RectF(NewarcLeft ,NewarcTop,NewarcRight,NewarcBottom);  

      //分配颜色
      PaintArc.setARGB(255,arrColorRgb[i][0], arrColorRgb[i][1], arrColorRgb[i][2]);

      //在饼图中显示所占比例
      canvas.drawArc(NewarcRF, CurrPer, Percentage, true, PaintArc);
      //计算百分比标签
      xcalc.CalcArcEndPointXY(cirX, cirY, radius - radius/2/2, CurrPer + Percentage/2);
			//标识
		  canvas.drawText(arrPerLabel[i],xcalc.getPosX(), xcalc.getPosY() ,PaintLabel);
      //下次的起始角度
      CurrPer += Percentage;
    }
    //外环
    PaintLabel.setStyle(Style.STROKE);
    PaintLabel.setColor(Color.GREEN);
    canvas.drawCircle(cirX,cirY,radius,PaintLabel); 

    canvas.drawText("author:xiongchuanliang", 10, ScrHeight - 200, PaintLabel);

	}

}

代码实现起来很容易，但这种图的设计创意确实非常好。 叹服。

一定要附上南丁格尔维基百科的链接:      http://zh.wikipedia.org/wiki/%E5%BC%97%E7%BE%85%E5%80%AB%E6%96%AF%C2%B7%E5%8D%97%E4%B8%81%E6%A0%BC%E7%88%BE

感兴趣的可以看看。