android 放大后的坐标

Question

我试图在缩放后绘制圆圈，但它没有绘制在正确的位置。没有变焦它工作正常。变焦后还需要考虑什么因素吗？像比例因子之类的东西。 圆的半径也随之增大。 即使在缩放后我也需要正确绘制。

      public boolean onTouch(View v, MotionEvent rawEvent) {
      WrapMotionEvent event = WrapMotionEvent.wrap(rawEvent);
          ImageView view = (ImageView) v;
      view.setScaleType(ImageView.ScaleType.MATRIX);

             if (isZoomRequired == false)  //draw circle when zoom is off.
             {
             x = (int) rawEvent.getX();
                 y = (int) rawEvent.getY();
                 r = SettingsActivity.brushsize;

                pcanvas.drawCircle(x, y, r, mPaint);
                layers[1] = new BitmapDrawable(bitmap);
                LayerDrawable layerDrawable = new LayerDrawable(layers);
            view.setImageDrawable(layerDrawable);

            }
            else    //zoom when zoom is on or button selected                      
            {
             // Handle touch events here...
             switch (event.getAction() & MotionEvent.ACTION_MASK) {
             case MotionEvent.ACTION_DOWN:
               savedMatrix.set(matrix);
               start.set(event.getX(), event.getY());
               Log.d(TAG, "mode=DRAG");
               mode = DRAG;
             break;
             case MotionEvent.ACTION_POINTER_DOWN:
               oldDist = spacing(event);
               Log.d(TAG, "oldDist=" + oldDist);
               if (oldDist > 10f) {
               savedMatrix.set(matrix);
               midPoint(mid, event);
               mode = ZOOM;
               Log.d(TAG, "mode=ZOOM");
               }
             break;
             case MotionEvent.ACTION_UP:
             case MotionEvent.ACTION_POINTER_UP:
               mode = NONE;
               Log.d(TAG, "mode=NONE");
             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) {
               float newDist = spacing(event);
               Log.d(TAG, "newDist=" + newDist);
               if (newDist > 10f) {
               matrix.set(savedMatrix);
               scale = newDist / oldDist;
               matrix.postScale(scale, scale, mid.x, mid.y);
               }
             }
             break;
         }


         view.setImageMatrix(matrix);

         }
     }

android中如何计算缩放后的x，y坐标？以及缩放后圆的半径。 任何帮助将不胜感激。

Answer 1

从你的代码中我不清楚你到底在做什么。但您可以完全控制如何绘制圆圈。您可以根据给定的缩放级别缩放圆的半径并使用新的半径重新绘制圆，或者根据缩放级别缩放画布的矩阵。

Answer 2

如果您使用 ScaleGestureDetector.SimpleOnScaleGestureListener 类，您可以执行以下操作：

@Override
public boolean onScaleBegin(ScaleGestureDetector detector){ 
   //the focal point before taking into account the zoom/translations/etc  
    float startX = detector.getFocusX();
    float startY = detector.getFocusY();

    initialPoints = new float[]{startX, startY};
        if(transformMatrix.invert(inverseTransformMatrix))
            inverseTransformMatrix.mapPoints(initialPoints );
      //initialPoints now contain the correct points based on the current zoom
}