Here’s one example of a Hype document scaling based on its width. By adjusting the group bounds, and setting scaling & flexible properties on the group, it will expand based on the available width of the Hype document:
scaling-width-shrink-fit.hype 3.zip (953.2 KB)
You can achieve different results if you change the boundary of the group so that it only encloses the actual content you want to never be cut off on the top or bottom, instead of the entirety of the scene. For example, try adjusting the group bounds to just fit the two squares – it will ensure they always fit the available space and are never cut off, but you can get the background image to stretch outside of the boundaries of the document.