LÖVE

Lovely Camera is a basic camera. It features target resolution, scaling mode, anchoring, optional black border, position, zoom, space conversions (screen to world, world to screen, screen to window, window to screen) and mouse position on those spaces (world and screen). If you want to do splitscreen, multiple cameras or any other advanced feature, it won't help you.

It works based on apply(), that is, it doesn't push or pop for you, it just applies the transformations when you tell it to do so. The demo shows usage.

https://github.com/mateusak/lovely-camera