Canvas gamecamera - locationtranslate values messed up by applied canvas scaling

I'm working on an android game and am currently busy with a gamecamera type of component. The best method seems to be translating the canvas (possibly with a matrix) to move the entire canvas to act like a gamecamera. (please correct me if I'm wrong).

this is all getting along pretty nicely, 开发者_高级运维the gamecamera is moving and the x and y values of the camera are being used as guidelines to translate the canvas location:

    public void onMove(float distanceX, float distanceY){

          Camera.x += (int) distanceX;
          Camera.y += (int) distanceY;
     }

     protected void onDraw(Canvas canvas) {

             canvas.translate(Camera.x, Camera.y);

             level.draw(canvas);

             //the text is a ui component so shouldn't move with the level
             canvas.restore();
             canvas.drawText(fps + " fps", 0, 32, textPaint);
       }

When trying to interact with the world I simply add the camera's coordinates to the touch's coordinates to get the correct point in the world:

      public void onSingleTap(MotionEvent event) {

        float mouseX = event.getX() - Camera.x;
        float mouseY = event.getY() - Camera.y;
     }

However, The user also has the choice to scale the screen, zooming to a point on the world.

case MotionEvent.ACTION_MOVE:

    if (MODE == ZOOM && event.getPointerCount() == 2) {

        float newDist = spacing(event);

        if (newDist > 10f) {

            Camera.zoom = newDist / PrevMultiDist;

            //the midpoint for the zoom
            midPoint(midpoint, event);
            Camera.setPivot(midpoint.x, midpoint.y);

            translateMatrix.postScale(Camera.zoom, Camera.zoom, Camera.pivotX, Camera.pivotY);
        }
    }
 break;

The zoom is messing up the world-touch translation coordinates since the view is being moved to zoom on the chosen spot. I think if I substract the zoom offset value from the camera location that I will get the correct position in the world again.

So the touchevent becomes something like this:

      public void onSingleTap(MotionEvent event) {
      //ideally the zoomoffset might be added in the camera's location already?
        float mouseX = event.getX() - Camera.x - zoomOffsetX;
        float mouseY = event.getY() - Camera.y - zoomOffsetY;
     }

I already found this question: Android get Bitmap Rect (left, top, right, bottom) on a Canvas but it doesn't provide the awsner I want and I can't figure out if his calculations can help me.

I feel like I'm missing something really simple. Hope someone can help!