Change draw area of tilemap??

[Sanic]

Basically, when I zoom out of a tilemap layer the draw region remains the same so the map ends up sitting in the top left corner of my screen when I zoom out:

[cap of the top left corner of my game screen, zoom at 0.5]

I've tried changing the layer width/height and the layer's canvas width/height but that just reverses the scaling.

What can I do to get the tilemap to draw the other areas when scaling?