I'm making a pixel art game with a small base resolution (640x360) with "letterbox integer scale" Fullscreen mode selected. I actually want it to be a bit more zoomed in than it is, and also want to use zoom effects that resolve onto integer scales (that is, that 1 pixel in the small resolution turns into an integer amount of pixels at larger resolutions evenly everywhere on the screen).
My problem is just that I can't figure out how "zoomed" the actual window is--I would refer to the canvas size, but I can't seem to find an expression that refers to the canvas size in the engine, even though it's tracked in the debug menu (though it *does* have the default canvas size expressions.) is there some other way to do this I haven't considered or am not seeing?
for instance if I fullscreen my game I know that the zoom is 4x (bc I know my resolution is 2560x1440), so I can add or remove 1 pixel width to every "base pixel" by changing the layout scale by increments of 1/4. obviously I won't know what resolution my players are playing at, so I want to be able to do it programmatically, with units of, say, 1/zoom, or something like 1/(canvasWidth/640). I just can't find the expression.