如何在圖像縮放時使用手指繪製圖像？

Question

我試圖在圖像放大時在圖像上繪製某些東西，但是當放大時，它會在觸摸和繪圖之間創建一些偏移，但沒有縮放，它工作得很完美。例如。

代碼的圖像變焦：

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

     canvas.concat(matrix); 
     .... 
    } 

@Override 
    public boolean onTouch(View v, MotionEvent event) { 
     ImageView view = (ImageView) v; 

     switch (event.getAction() & MotionEvent.ACTION_MASK) { 
      case MotionEvent.ACTION_DOWN: 
       savedMatrix.set(matrix); 
       start.set(event.getX(), event.getY()); 
       mode = DRAG; 
       lastEvent = null; 
       break; 

      case MotionEvent.ACTION_POINTER_DOWN: 
       oldDist = spacing(event); 
       if (oldDist > 10f) { 
        savedMatrix.set(matrix); 
        midPoint(mid, event); 
        mode = ZOOM; 
       } 
       lastEvent = new float[4]; 
       lastEvent[0] = event.getX(0); 
       lastEvent[1] = event.getX(1); 
       lastEvent[2] = event.getY(0); 
       lastEvent[3] = event.getY(1); 
       d = rotation(event); 
       break; 

      case MotionEvent.ACTION_UP: 
      case MotionEvent.ACTION_POINTER_UP: 
       mode = NONE; 
       lastEvent = null; 
       break; 

      case MotionEvent.ACTION_MOVE: 
       if (mode == DRAG) { 
        matrix.set(savedMatrix); 
        matrix.postTranslate((event.getX() - start.x), (event.getY() - start.y)); 
       } else if (mode == ZOOM && event.getPointerCount() == 2) { 
        float newDist = spacing(event); 
        matrix.set(savedMatrix); 
        if (newDist > 10f) { 
         float scale = newDist/oldDist; 
         matrix.postScale(scale, scale, mid.x, mid.y); 
        } 
        if (lastEvent != null) { 
         float newRot = rotation(event); 
         float r = newRot - d; 
         matrix.postRotate(r, view.getMeasuredWidth()/2, view.getMeasuredHeight()/2); 
        } 
       } 
       break; 
     } 
     invalidate(); 

     return true; 
    } 

代碼繪製：

@Override 
    public boolean onTouch(View view, MotionEvent event) { 

     float x = event.getX(); 
     float y = event.getY(); 

     switch (event.getAction()) { 
      case MotionEvent.ACTION_DOWN: 
       touchStart(x, y); 
       invalidate(); 
       break; 
      case MotionEvent.ACTION_MOVE: 
       touchMove(x, y); 
       invalidate(); 
       break; 
      case MotionEvent.ACTION_UP: 
       touchEnd(); 
       invalidate(); 
       break; 
     } 

     return true; 
    } 

    private void touchMove(float x, float y) { 
     float f1 = Math.abs(x - mX); 
     float f2 = Math.abs(y - mY); 
     if ((f1 >= 4.0F) || (f2 >= 4.0F)) { 
      path.quadTo(mX, mY, 
        (x + mX)/2.0F, 
        (y + mY)/2.0F); 
      mX = x; 
      mY = y; 
     } 
    } 

    private void touchStart(float x, float y) { 
     path.reset(); 
     path.moveTo(x, y); 
     blurView.pathList.add(path); 
     blurView.strokeWidthList.add(strokeWidth); 
     mX = x; 
     mY = y; 
    } 

    private void touchEnd() { 
     path.lineTo(mX, mY); 
     path = new Path(); 
    } 

任何一個可以幫我要如何處理的比例因子或如何刪除圖像放大縮放因子進入手指觸摸。

Answer 1

您通常會存儲比例因子，並將許多座標處理系統乘以其值。

就是這樣。