画布，路径方向改变

Question

我使用此示例代码来捕获信用卡签名 - http://corner.squareup.com/2010/07/smooth-signatures.html。我不知道如何在方向改变时缩放路径/画布。我使用View的onSizeChange回调：

  @Override
  protected void onSizeChanged(int w, int h, int oldw, int oldh) {
      //View given size
      super.onSizeChanged(w, h, oldw, oldh);

      Log.d("Signature Old Height", String.valueOf(oldh));
      Log.d("Signature Height", String.valueOf(h));
      Log.d("Signature Old Width", String.valueOf(oldw));
      Log.d("Signature Width", String.valueOf(w));

      if(mCanvas != null){
          Matrix scaleMatrix = new Matrix(); 

          scaleMatrix.setScale((float)oldw/(float)w, (float)oldh/(float)h);
          path.transform(scaleMatrix);
          mCanvas.drawPath(path, paint);
      }
  }

但我的工作不正常。