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;

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。

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