[webkit-changes] [WebKit/WebKit] a516b8: Handle moving a UI-side composited window between ...

[Simon Fraser]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: a516b8527e73e0a16dfd0c660ca4ebd8d9b6130c
      https://github.com/WebKit/WebKit/commit/a516b8527e73e0a16dfd0c660ca4ebd8d9b6130c
  Author: Simon Fraser <simon.fraser at apple.com>
  Date:   2023-01-05 (Thu, 05 Jan 2023)

  Changed paths:
    M Source/WebKit/Shared/RemoteLayerTree/RemoteLayerBackingStore.h
    M Source/WebKit/Shared/RemoteLayerTree/RemoteLayerBackingStore.mm
    M Source/WebKit/WebProcess/WebPage/RemoteLayerTree/PlatformCALayerRemote.cpp
    M Source/WebKit/WebProcess/WebPage/mac/RemoteLayerTreeDrawingAreaMac.mm

  Log Message:
  -----------
  Handle moving a UI-side composited window between displays with different properties
https://bugs.webkit.org/show_bug.cgi?id=247932
rdar://102346937

Reviewed by Tim Horton

On macOS windows can be moved between displays with different colorspaces, so with
UI-side compositing we need to ensure that we update layer backing stores with the
new colorspace.

To fix this, add the colorspace to RemoteLayerBackingStore::Parameters, and initialize
it in PlatformCALayerRemote::updateBackingStore() by getting the colorspace from the
RemoteLayerTreeContext (on macOS). This allows the existing call to `ensureBackingStore()`
to do the right thing when the colorspace changes.

We rely on the fact that moving between displays triggers repaints in all layers already
to make sure that we hit PlatformCALayerRemote::updateBackingStore().

* Source/WebKit/Shared/RemoteLayerTree/RemoteLayerBackingStore.h:
(WebKit::RemoteLayerBackingStore::Parameters::operator== const):
(WebKit::RemoteLayerBackingStore::colorSpace const):
* Source/WebKit/Shared/RemoteLayerTree/RemoteLayerBackingStore.mm:
(WebKit::RemoteLayerBackingStore::pixelFormat const):
(WebKit::RemoteLayerBackingStore::colorSpace const): Deleted.
* Source/WebKit/WebProcess/WebPage/RemoteLayerTree/PlatformCALayerRemote.cpp:
(WebKit::PlatformCALayerRemote::updateBackingStore):
* Source/WebKit/WebProcess/WebPage/mac/RemoteLayerTreeDrawingAreaMac.mm:
(WebKit::RemoteLayerTreeDrawingAreaMac::setColorSpace):

Canonical link: https://commits.webkit.org/258486@main