Draw mat at postion into different mat?

Hi! I'm trying to draw a small image at position x/y into a big background image. I didn't find a way to do this with opencv4nodejs.

I'm aware of `copyTo()` ... but as both mats have to have the same size, it doesn't solve my problem.

```
const region = new cv.Rect(x, y, width, height)
small.copyTo(large.getRegion(region))
```

Any hints?