Webtiles mobile/tablet tracking issue

[rawlins]

This issue is a continuation of #2332 and #2221, since there's a fair amount of remaining undone work. Most of what's here is based on my notes from testing in iOS.

Major issues

• virtual keyboard, added in Feature request: webtiles: bring up the on-screen keyboard on iPadOS, iOS #2221 and subsequent commits. Detail work probably still ongoing.
• phone usability. It remains unclear if it's at all practical to really get dcss playable on a phone, but it might be possible to get it closer to a position where someone could log in and do a few things. What would this take?

Non-platform-specific

• The lack of esc is a big problem. E.g. it's very hard to get out of X view. (Looks like this would apply to both Android and iOS.) Edit: workaround added in 6e7a31e, trying out backspace for this role.
• Other hard or impossible keys to access: tab, scroller navigation keys (but touch scrolling works). Ctrl-keys available via *, but a lot of players don't know about this. Movement requires vikey knowledge, isn't very natural. Should there be a touch binding?
• tap and hold for right click would be very helpful. (I took a stab at implementing this for the dungeon view, see below, and couldn't figure it out in a few-hours attempt. It seemed like one issue on iOS at least was that the browser terminated all touch events at 500ms for its own tap-and-hold handling.)
• dungeon tapping feels laggy. I at first wasn't sure if this was something about my devices or what, but I've since learned that by default click events via touch have a 300ms delay built in in case the user wants to double-tap to zoom, and I'm pretty sure this is it. It may be better to use touchstart/end more generally at some point. Only tested on iOS but from reading this is likely general. I have a half-backed implementation of some of this (plus an attempt at tap-and-hold, see above) but it was very hard to get right, so I dropped it until I have more time.
• testing with a typical external keyboard needed?
• at the default zoom levels on a table, many tappable UI elements are sized a bit too small. (Tested only on iOS but I expect this is general.)

Android

I don't have access to an android device so others will have to provide feedback

iOS

• The UI behaves quite badly with the default (non-popout) keyboard. Work around the iOS shift effect somehow?
  • Links for future reference: https://blog.opendigerati.com/the-eccentric-ways-of-ios-safari-with-the-keyboard-b5aa3f34228d?gi=a9f920adc42 https://medium.com/@im_rahul/safari-and-position-fixed-978122be5f29
• Popout keyboard was fine, but on my iPad (9.7") there wasn't a good place to put it that didn't cover something important. (Related: minimap doesn't seem to scale?)
• Sometimes, zoom is initially set wrong (during the loading display), can't replicate this on demand. I think it mostly happens on a reload.
• Horizontal height calculations. The infamous 100vh issue is a problem for us, since we do use vh for ui popup sizing. a885d4b provided a workaround but not actually a fix.
• the techniques needed to keep the keyboard up are somewhat ugly and still flaky. Bugfixing needed.

others

• Right now touch laptops will by default trigger the input box, which is probably annoying. Solutions include better device detection (hard), and changing the default for tile_web_mobile_input_helper to false.

small screen / responsive issues

• Popups are appearing at a font size that doesn't fit 79 columns of text on the screen. The simplest fix would be to just figure out how to get them to scale down, since the requirement for 79 columns is based on the underlying terminal behavior. Scaling should be possible as e.g. the HUD is at a size that would make this work. See Truncated popups on mobile viewport #2262
• Scrolling on mobile with a popup open makes it too easy to close the popup, the close tap detection should filter scrolling somehow.