Bags not (hardcoded) resizing correctly

[Imadruid]

I am working on a bag mod, but I am having trouble with the code that resizes them automatically. I really don't want to make player resizeable bags, but I may have to. Has anyone been able to create a bag mod that had smaller icons/buttons and autosized correctly. If so, what is the formula they are using to determine how big to make the window.