1316949 - Support page navigation by swipe

Status: RESOLVED WONTFIX

(Focus-iOS :: General, enhancement)

Description

[Aaron Train [:aaronmt]]

I can barely operate back and forward page navigation of the browser on my iPhone 7 with one hand.

Support swipe.

Comment 1

[J. Longman]

Just to note that I took some time to look into doing this. NB I'm not an iOS expert.  

- Simply adding a SwipeGestureRecognizer will interfere with panning around a document.
-- There's some subtlety which is proximity to screen edges when starting the swipe, close to edge = visit browser history, "far" from edges = pan document.

- Firefox for iOS achieves this subtlety by using a WKWebView, but WKWebView's don't appear to support content blocking. 
-- more detail, ContentBlockers are loaded using NSURLProtocol, WKWebView does not support NSURLProtocol: https://bugs.webkit.org/show_bug.cgi?id=138169

Putting more effort into the edge-detecting swipe gesture seems where effort should be directed. I kind of assume based on the nature of Focus that keeping a screenshot of forward and back history is not desirable so that should simplify the implementation. (I'm assuming that WKWV uses a screenshot when it reveals forward and backwards swiping, maybe it has full state, w/e.)

Comment 2

[Brian Nicholson (:bnicholson)]

(In reply to J. Longman from comment #1)
> I kind of assume based on the nature of Focus that
> keeping a screenshot of forward and back history is not desirable

I think using screenshots for the back/forward list is fine as long as we clear them when we erase the session. That said, we'll accept a PR that doesn't use screenshots for the initial implementation; that's something we can tweak later.

Comment 3

[Barbara Bermes [:barbara] - NI please!]

closing this one in favour of https://github.com/mozilla-mobile/focus-ios/issues/90