[webkit-changes] [WebKit/WebKit] 1b857d: [iOS] Pinch zooming then fullscreening causes full...

[Jer Noble]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 1b857d6d225136cda2fb75066538ca6798845d80
      https://github.com/WebKit/WebKit/commit/1b857d6d225136cda2fb75066538ca6798845d80
  Author: Jer Noble <jer.noble at apple.com>
  Date:   2024-02-12 (Mon, 12 Feb 2024)

  Changed paths:
    M Source/WebKit/UIProcess/API/Cocoa/WKWebViewInternal.h
    M Source/WebKit/UIProcess/API/ios/WKWebViewIOS.h
    M Source/WebKit/UIProcess/API/ios/WKWebViewIOS.mm
    M Source/WebKit/UIProcess/ios/fullscreen/WKFullScreenWindowControllerIOS.mm

  Log Message:
  -----------
  [iOS] Pinch zooming then fullscreening causes fullscreen presentation to be zoomed unexpectedly
https://bugs.webkit.org/show_bug.cgi?id=269195
rdar://121898126

Reviewed by Andy Estes.

The intent of the fullscreen presentation on iOS is to disable zooming & lock the zoom level to an
extent to which the entire contents of the fulscreen element are visible in the viewport. However,
the web page itself can change the minimum and maximum zoom levels (and even the current zoom
level). When this happens, it breaks the expected behavior of fullscreen mode, which is to show the
entire contents of the fullscreen element in the viewport.

The previous implementation attempted to save and restore the min, max, and current zoom levels when
entering and exiting fullscreen, assuming those levels would not be re-set during fullscreen mode.
This assumption was not met. Instead, add an IPI to override zoom levels sent by the page during
rendering, and a matching IPI to remove that override. Only the current zoom level is saved and restored.

* Source/WebKit/UIProcess/API/Cocoa/WKWebViewInternal.h:
* Source/WebKit/UIProcess/API/ios/WKWebViewIOS.h:
* Source/WebKit/UIProcess/API/ios/WKWebViewIOS.mm:
(-[WKWebView _updateScrollViewForTransaction:]):
(-[WKWebView _overrideZoomScaleParametersWithMinimumZoomScale:maximumZoomScale:allowUserScaling:]):
(-[WKWebView _clearOverrideZoomScaleParameters]):
* Source/WebKit/UIProcess/ios/fullscreen/WKFullScreenWindowControllerIOS.mm:
(WebKit::WKWebViewState::applyTo):
(WebKit::WKWebViewState::store):
(-[WKFullScreenWindowController enterFullScreen:]):
(-[WKFullScreenWindowController _reinsertWebViewUnderPlaceholder]):

Canonical link: https://commits.webkit.org/274503@main