Canvas clipPath僅適用於Android模擬器

Question

我正在嘗試使用canvas.clipPath（）在類似於APP演示中的Clipping活動的約束圓內繪制位圖圖像。 問題是我的代碼只能在模擬器上正確呈現，而在實際的Samsung Galaxy Nexus 4.2上運行時，它看起來好像clipPath的工作方式更像是矩形裁剪。 我完全迷住了！ 我創建一個新的Path（）並在視圖ctor中解碼一個位圖。 有什么建議么？

@Override
protected void onDraw(Canvas canvas) {
    Point point = getPoint();
    path.reset();
    canvas.clipPath(path); // makes the clip empty
    path.addCircle(point.x, point.y, getScale() * 140, Path.Direction.CCW);
    canvas.clipPath(path, Region.Op.REPLACE);

    Point scaledSize = new Point((int) (bitmapSize.x * getScale()), (int) (bitmapSize.y * getScale()));
    Point topLeft = new Point((point.x - (scaledSize.x / 2)), (point.y - (scaledSize.y / 2)));
    canvas.drawBitmap(bitmap, null, new Rect(topLeft.x, topLeft.y, topLeft.x + scaledSize.x, topLeft.y + scaledSize.y), paint);
}

Galaxy Nexus

仿真器

Answer 1

ClipPath不支持硬件加速

您可以使用以下命令關閉硬件加速：

setLayerType(View.LAYER_TYPE_SOFTWARE, null);

Answer 2

clipPath不支持硬件加速。 您可以使用以下方式創建裁剪的位圖：

Bitmap clippedBitmap = ... // Create same size bitmap as source
Paint paint = new Paint();
Canvas canvas = new Canvas(clippedBitmap);
paint.setColor(Color.RED);
paint.setStyle(PAint.Style.FILL);
paint.setFilterBitmap(true);
canvas.drawCircle(cx, cy, radius, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));    
canvas.drawBitmap(sourceBitmap, 0, 0, paint);

這樣做一次，然后繪制剪切的位圖而不是源位圖

Answer 3

ClipPath不支持硬件加速。 檢查下面主題不支持的圖形操作下的鏈接。

http://developer.android.com/guide/topics/graphics/hardware-accel.html#drawing-support

您可以使用以下內容作為參考，並修改繪制圓的參數以適合您的需要。

public class MainActivity extends Activity
{
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    DrawingView dv = new DrawingView(this);
    dv.setBackgroundColor(Color.RED);
    setContentView(dv);
}

class DrawingView extends View{
Bitmap bitmap;


 public DrawingView(Context context)
 {
 super(context);
 bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.sqaure);   
}


@Override
public void onDraw(Canvas canvas)
{
 Paint paint = new Paint();
 //paint.setStyle(Paint.Style.FILL);
 // paint.setColor(Color.CYAN);
 canvas.drawBitmap(getclip(), 0, 0, paint);//originally x and y is o and o .

 } 
 public Bitmap getclip()
 {
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
        bitmap.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(),
        bitmap.getHeight());
paint.setColor(Color.RED);
paint.setStyle(Paint.Style.FILL);
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
//paint.setColor(color);
canvas.drawCircle(bitmap.getWidth() / 2-40,
        bitmap.getHeight() / 2, bitmap.getWidth() / 2-40, paint);
    // change the parameters accordin to your needs.
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;
    }
  } 
}