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A response to the section on "How Can I Determine the Size and Position of Descendants of Peers?" Using onGloballyPositioned (or onSizeChanged, or similar modifiers) like this is a quick way to get yourself into trouble with layouts that take multiple frames to resolve that can flash or look janky.

When you have composition being driven by information that you can only get in a later phase, like measurement, layout or drawing, the first composition can't be correct! This means that the first frame might be blank, or components might jump around as you get more info.

This can also wreck havoc on animations - maybe they can cover up some of the jankiness, but animations need to have a consistent view of the layout as it animates at each point in time. Shared element transitions don't really work if the shared element disappears completely for a frame.

Unfortunately there's not really a one-size-fits-all solution for every case, but don't be afraid of a custom layout - if you're already doing some math to change the layout of something based on something else, you're about 80% of the way there to writing a custom layout.

This video from last year goes into a lot more detail about the problem space here, along with some examples of how to approach different problems: www.youtube.com/watch?v=PUxt...