Multi-threaded on alpinemaps.org (not all versions work on iphone)

[adam-ce]

going through the versions on https://gataki.cg.tuwien.ac.at/ and testing with chrome / safari on iOS:
non-threaded versions work. threaded versions go out of memory. maybe we need to limit the memory size for the web workers.

[adam-ce]

ios user agent strings:
safari: Mozilla/5.0 (iPhone; CPU iPhone OS 16_5 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.5 Mobile/15E148 Safari/604.1

chrome: Mozilla/5.0 (iPhone; CPU iPhone OS 16_5 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/113.0.5672.121 Mobile/15E148 Safari/604.1

[adam-ce]

also crashes in the single threaded version after some time. probably the limit is around 300mib (thanks for the link joey):
https://stackoverflow.com/questions/74506298/how-much-the-memory-limitation-is-on-the-ios-device-browser

[adam-ce]

for the memory limit, we can't detect that beforehand. so we probably want a watchdog implemented in JS with the following algorithm:

start multithreaded -> if it crashes, start singlethreaded -> if it crashes, start singlethreaded with a tighter tile limit.

i don't know whether this can even work, or the whole tab crashes and JS stops working altogether.