안드로이드에서 손가락 지우개를 구현하는 방법은 무엇입니까?

Question

내 페인트에서 하나의 페인트 앱을 준비했습니다. 어떤 것이 든 그릴 수 있습니다. 잘 작동합니다. 지우개 페인트를 지우려면 손가락 지우기를 준비하십시오. 다음 코드를 준비했습니다.

이 코드는

mMyPaint.setOnTouchListener(new OnTouchListener() { 
      public boolean onTouch(View v, MotionEvent event) { 
       if(paintAndEraserFlag==0){ 
        if (event.getAction() == MotionEvent.ACTION_DOWN) { 
        // path = new Path(); 
        mPath.moveTo(event.getX(), event.getY()); 
        mPath.lineTo(event.getX(), event.getY()); 
        mArryLstPath.add(mPath); 
       } else if (event.getAction() == MotionEvent.ACTION_MOVE) { 
        mPath.lineTo(event.getX(), event.getY()); 

       } else if (event.getAction() == MotionEvent.ACTION_UP) { 
        mPath.lineTo(event.getX(), event.getY()); 
       } 
       }else if(paintAndEraserFlag==1){ 
        if (event.getAction() == MotionEvent.ACTION_DOWN) { 
        // path = new Path(); 
         System.out.println("in path---"); 
        mPath.moveTo(event.getX(), event.getY()); 
        mPath.lineTo(event.getX(), event.getY()); 
        mArryLstEarser.add(mEraserPath); 
       } else if (event.getAction() == MotionEvent.ACTION_MOVE) { 
        mPath.lineTo(event.getX(), event.getY()); 

       } else if (event.getAction() == MotionEvent.ACTION_UP) { 
        mPath.lineTo(event.getX(), event.getY()); 
       } 
       } 

       mMyPaint.invalidate(); 
       return true; 

      } 
     }); 

내 페인트 및 지우개 객체,

mPaint.setDither(true); 
     mPaint.setColor(0xFFD2691E); 
     mPaint.setStyle(Paint.Style.STROKE); 
     mPaint.setStrokeJoin(Paint.Join.ROUND); 
     mPaint.setStrokeCap(Paint.Cap.ROUND); 
     mPaint.setStrokeWidth(30); 

     mEraser.setDither(true); 
     mEraser.setStyle(Paint.Style.STROKE); 
     mEraser.setStrokeJoin(Paint.Join.ROUND); 
     mEraser.setStrokeCap(Paint.Cap.ROUND); 
     mEraser.setStrokeWidth(15); 
     mEraser.setColor(0x00000000); 

이 있습니다 사용자 지정보기에 내 무승부에 방법,

public void onDraw(Canvas canvas) { 

     if (myDrawBitmap == null) { 
      myDrawBitmap = Bitmap.createBitmap(480, 800, 
        Bitmap.Config.ARGB_8888); 
      mBmpDrawCanvas = new Canvas(myDrawBitmap); 
      mIntDrawArray = new int[myDrawBitmap.getWidth() 
        * myDrawBitmap.getHeight()]; 
     } 

     if (mBmpDrawCanvas != null) { 
      myDrawBitmap.getPixels(mIntDrawArray, 0, myDrawBitmap.getWidth(), 
        0, 0, myDrawBitmap.getWidth(), myDrawBitmap.getHeight()); 
      if (MyEraserActivity.paintAndEraserFlag == 0) { 
       for (Path path : MyEraserActivity.mArryLstPath) { 

        mBmpDrawCanvas.drawPath(MyEraserActivity.mPath, mPaint); 

       } 
      } else if (MyEraserActivity.paintAndEraserFlag == 1) { 
       for (Path path : MyEraserActivity.mArryLstEarser) { 

        mBmpDrawCanvas.drawPath(MyEraserActivity.mEraserPath, 
          mEraser); 
        System.out.println("in eraser---"); 
       } 
      } 
      if (myDrawBitmap != null) 
       canvas.drawBitmap(myDrawBitmap, 0, 0, null); 

     } 

    } 

그려진 페인트가 있으면 터치하는 부분을 지우고 싶습니다. 저를 도와주세요. 그것은 수도

Answer 1

는 당신을 도와줍니다 : 비트 맵이하는 동안

mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR)); 

Answer 2

캔버스 지우개를 지원하지 않습니다.

기본 해결 흐름 :

1. 만들기 다른 캔버스

2. 그 캔버스

   public void init(int width, int height) { 
       Log.i(TAG,"init with "+width+"x"+height); 
       foreground = Bitmap.createBitmap(width, height, Config.ARGB_8888); 
       cacheCanvas = new Canvas(); 
       cacheCanvas.setBitmap(foreground); 
   } 
   

3. 기록이의 접촉에 비트 맵

4. 설정을 비트 맵 만들기 비트 맵, 페인트 및 지우개

   public boolean onTouchEvent(MotionEvent event) { 
   // Log.i(TAG,"onTouch detected"); 
   float eventX = event.getX(); 
   float eventY = event.getY(); 
   
   switch (event.getAction()) { 
   case MotionEvent.ACTION_DOWN: 
       currentStroke = new Stroke(); 
       currentStroke.color = paint; 
       currentStroke.path.moveTo(eventX, eventY); 
       currentStroke.path.lineTo(eventX, eventY); 
   
       synchronized (strokes) { 
        strokes.add(currentStroke); 
       } 
       lastTouchX = eventX; 
       lastTouchY = eventY; 
       // There is no end point yet, so don't waste cycles invalidating. 
       return true; 
   
   case MotionEvent.ACTION_MOVE: 
   case MotionEvent.ACTION_UP: 
       // Start tracking the dirty region. 
       resetDirtyRect(eventX, eventY); 
   
       // When the hardware tracks events faster than they are delivered, 
       // the 
       // event will contain a history of those skipped points. 
       int historySize = event.getHistorySize(); 
       for (int i = 0; i < historySize; i++) { 
        float historicalX = event.getHistoricalX(i); 
        float historicalY = event.getHistoricalY(i); 
        expandDirtyRect(historicalX, historicalY); 
        if (i == 0) { 
         lastX = historicalX; 
         lastY = historicalY; 
         currentStroke.path.lineTo(historicalX, historicalY); 
        } else { 
         currentStroke.path.quadTo(lastX, lastY, 
           (historicalX + lastX)/2, 
           (historicalY + lastY)/2); 
        } 
       } 
   
       // After replaying history, connect the line to the touch point. 
       if(historySize==0){ 
        long duration=event.getEventTime()-event.getDownTime(); 
        float offset=0.1f; 
        if(duration<300){ 
         offset=50.0f/duration; 
        } 
        currentStroke.path.lineTo(eventX+offset, eventY+offset); 
       }else{ 
        currentStroke.path.lineTo(eventX, eventY); 
       } 
       synchronized (strokes) { 
        strokes.add(currentStroke); 
       } 
   
       break; 
   
   default: 
       // Log.i(TAG,"Ignored touch event: " + event.toString()); 
       return false; 
   } 
   
   // Include half the stroke width to avoid clipping. 
   float width = paint.getStrokeWidth()/2; 
   invalidate((int) (dirtyRect.left - width), 
        (int) (dirtyRect.top - width), (int) (dirtyRect.right + width), 
        (int) (dirtyRect.bottom + width)); 
   
   lastTouchX = eventX; 
   lastTouchY = eventY; 
   
   return true; 
   } 
   

5. 내가 u는 여기에서 언급하지만이 코드에 몇 가지 문제가 동일한 코드를 사용하고

   protected void onDraw(Canvas canvas) { 
   // Log.i(TAG,"onDraw called"); 
   synchronized (strokes) { 
       if (strokes.size() > 0) { 
        for (Stroke s : strokes) { 
         cacheCanvas.drawPath(s.path, s.color); 
        } 
        canvas.drawBitmap(foreground, 0, 0, null); 
        strokes.clear(); 
       } 
   } 
   }