Right now we do it whenever the platform views preview flag is on.
This is less efficient, filed
https://github.com/flutter/flutter/issues/24133 to only do this when
there's a platform view in the tree.
Moved the frame buffer specific logic from IOSGLContext to IOSGLRenderTarget.
use recording canvases for overlays
Support platform view overlays with gl rendering.
This also changes the overlay canvases (for both software and gl
rendering) be recording canvases, and only rasterize them after
finishing the paint traversal.
Handing a UIView refererence directly to the engine makes it challenging
for plugin authors to retain a controller for that UIView (e.g the
controller that talks over the platform channel) for as long as the
embedded view is needed.
We instead make the factory return a FlutterPlatformView which is a
wrapper around the UIView that the engine retains as long as the
platform view instance is needed. This allows plugin authors to keep
their control logic in the FlutterPlatformView and know that the engine
is responsible for retaining the reference.
When we visit a PlatformViewLayer during the paint traversal it replaces
the PaintContext's canvas with a new one that is painted ontop of the
embedded view.
We need to make sure that operations applied by parent layers are also
applied to the new canvas.
To achieve this we collect all the canvases in a SkNWayCanvas and use
this canvas by non leaf nodes. Leaf nodes still paint only to the "current"
canvas.
This PR moves the overlay canvas creation from the paint phase to the
preroll phase, collects them into a SkNWayCanvas and set it in
PaintContext.
To keep this PR focused, I only used the internal_nodes_canvas in the
tranform_layer.
Will followup with a PR that changes all internal layers to use the
internal_nodes_canvas.
When the flag is true, we currently use a single thread configuration,
and disabled the raster cache for opacity layers.
The flag's name is 'io.flutter_embedded_views_preview'.
The platform views embedding is still WIP, and until we dynamically
merge the gpu and platform threads based on the presence of an embedded
view in the scene fetching the view embedder is not thread safe.
This PR essentially disables iOS platform views embedding, we will
re-enable once dynamic thread merging is supported.
For flow to manipulate the embedded UIViews during the paint traversal
it needs some hook in PaintContext.
This PR introduces a ViewEmbeder interface that is implemented by the
iOS PlatformViewsController and plumbs it into PaintContext.
The ViewEmbedder interface is mainly a place holder at this point, as
this PR is focused on just the plumbing.
TL;DR: Offscreen surface is created on the render thread and device to host
transfer performed there before task completion on the UI thread.
While attempting to snapshot layer trees, the engine was attempting to use the
IO thread context. The reasoning was that this would be safe to do because any
textures uploaded to the GPU as a result of async texture upload would have
originated from this context and hence the handles would be valid in either
context. As it turns out, while the handles are valid, Skia does not support
this use-case because cross-context images transfer ownership of the image from
one context to another. So, when we made the hop from the UI thread to the IO
thread (for snapshotting), if either the UI or GPU threads released the last
reference to the texture backed image, the image would be invalid. This led to
such images being absent from the layer tree snapshot.
Simply referencing the images as they are being used on the IO thread is not
sufficient because accessing images on one context after their ownership has
already been transferred to another is not safe behavior (from Skia's
perspective, the handles are still valid in the sharegroup).
To work around these issues, it was decided that an offscreen render target
would be created on the render thread. The color attachment of this render
target could then be transferred as a cross context image to the IO thread for
the device to host tranfer.
Again, this is currently not quite possible because the only way to create
cross context images is from encoded data. Till Skia exposes the functionality
to create cross-context images from textures in one context, we do a device to
host transfer on the GPU thread. The side effect of this is that this is now
part of the frame workload (image compression, which dominate the wall time,
is still done of the IO thread).
A minor side effect of this patch is that the GPU latch needs to be waited on
before the UI thread tasks can be completed before shell initialization.
Also adds //flutter/benchmarking which, similar to //flutter/testing, allows for the creation of a benchmarking executable. This is also the target that contains benchmarking utilities.
- Switch core snapshot to Dart 2 and remove support for loading platform.dill.
- Remove support for loading script snapshots.
- Remove support for loading source.
- Remove settings and fix names to reflect the above.
- Remove support for loading the service isolate from source.
When these delegate methods were initially added, it was expected that a single
shell would be able to own mutliple platform views, engines and animators. This
plan was abandoned in favor of creating multiple shells with their own platform
views, engines, etc.. The arguments were meant to ease the disambiguate the
instances of the variaous objects managed by the shell. This is no longer
necessary.
This change adds a delay before Animator::BeginFrame calls its
delegate's OnAnimatorNotifyIdle. This is because under certain
workloads, such as our parent view resizing us, which is communicated
via viewport change events, we won't have a frame scheduled yet in the
animator, despite the fact that we will go on to schedule a frame once
the viewport event arrives.
In Fuchsia's resizing performance test, on our reference high end x86-64
hardware, the previous logic was resulting in a ~45ms garbage collection
right after the first frame of an animation.
* Flush all embedded Android view on hot restart.
Adds an OnEngineRestarted method to PlatformView, this is currently only
implemented for Android where we need to use it for embedded views.
* review comments followup
* rename to OnPreEngineRestart, call before Clone
