在Android中Paint.StrokeWidth = 1的drawLine問題

我想我碰到了一個討厭的bug。的問題是，幾乎水平線具有輕微的梯度，並使用與StrokeWidth一個Paint = 1不繪製，例如：在Android中Paint.StrokeWidth = 1的drawLine問題

public class MyControl extends View { 

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

    @Override 
    protected void onDraw(Canvas canvas) 
    { 
      super.onDraw(canvas); 

     Paint pen = new Paint(); 
     pen.setColor(Color.RED); 
     pen.setStrokeWidth(1); 
     pen.setStyle(Paint.Style.STROKE); 

      canvas.drawLine(100, 100, 200, 90, pen); //not painted 
      canvas.drawLine(100, 100, 200, 100, pen); 
      canvas.drawLine(100, 100, 200, 110, pen); //not painted 
      canvas.drawLine(100, 100, 200, 120, pen); //not painted 
      canvas.drawLine(100, 100, 200, 130, pen); 

      pen.Color = Color.MAGENTA; 
      pen.setStrokeWidth(2); 

      canvas.drawLine(100, 200, 200, 190, pen); 
      canvas.drawLine(100, 200, 200, 200, pen); 
      canvas.drawLine(100, 200, 200, 210, pen); 
      canvas.drawLine(100, 200, 200, 220, pen); 
      canvas.drawLine(100, 200, 200, 230, pen); 
    }

}

並採用MyControl類這種方式：

public class prova extends Activity { 
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 

      MyControl ctrl = new MyControl(this); 
      setContentView(ctrl); 
    }

}

將StrokeWidth設置爲0或大於1，繪製所有線。

任何人都可以提出這個問題或者我應該提交這個問題作爲Android Issue？

在此先感謝！

來源

2011-03-21 Narcís Calvet

通過strokeWidth設置爲0，你說的Android與髮絲寬度（這通常是一個1px的任何設備上）來繪製。如果將筆觸寬度設置爲1，則該值將被縮放，即在ldpi設備上它將爲0.75 * 1 = 0.75px。所以這條線可能根本沒有渲染。設置ANTI_ALIAS_FLAG到您的油漆設備可能會有所幫助：

Paint pen = new Paint(Paint.ANTI_ALIAS_FLAG);

或者，你可以計算出筆畫寬度的電流密度：

pen.setStrokeWidth(1/getResources().getDisplayMetrics().density);

來源

2011-03-21 14:38:25

使用 Paint pen = new Paint(Paint.ANTI_ALIAS_FLAG);

來源

2011-03-21 14:14:53 Lumis

在Android中Paint.StrokeWidth = 1的drawLine問題

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