For embedder code that is configured for both AOT and JIT mode Dart execution
based on the Flutter engine being linked to, this runtime check may be used to
appropriately configure the `FlutterProjectArgs`. In JIT mode execution, the
kernel snapshots must be present in the Flutter assets directory specified in
the `FlutterProjectArgs`. For AOT execution, the fields `vm_snapshot_data`,
`vm_snapshot_instructions`, `isolate_snapshot_data` and
`isolate_snapshot_instructions` (along with their size fields) must be specified
in `FlutterProjectArgs`.
The contents rendered into the backing stores are already correctly scaled.
The initial implementation assumed this also held true for the metrics obtained
via embedded view parameters.
Fixes b/142699417
Embedders may use this to specify a thread whose event loop is managed by them
instead of the engine. In addition, specifying the same task runner for both
the platform and render task runners allows embedders to effectively perform
GPU rendering operations on the platform thread.
To affect this change, the following non breaking changes to the API have been
made:
* The `FlutterCustomTaskRunners` struct now has a new field `render_task_runner`
for the specification of a custom render task runner.
* The `FlutterTaskRunnerDescription` has a new field `identifier`. Embedders
must supply a unique identifier for each task runner they specify. In
addition, when describing multiple task runners that run their tasks on the
same thread, their identifiers must match.
* The embedder may need to process tasks during `FlutterEngineRun` and
`FlutterEngineShutdown`. However, the embedder doesn't have the Flutter engine
handle before `FlutterEngineRun` and is supposed to relinquish handle right
before `FlutterEngineShutdown`. Since the embedder needs the Flutter engine
handle to service tasks on other threads while these calls are underway,
there exist opportunities for deadlock. To work around this scenario, three
new calls have been added that allow more deliberate management of the Flutter
engine instance.
* `FlutterEngineRun` can be replaced with `FlutterEngineInitialize` and
`FlutterEngineRunInitialized`. The embedder can obtain a handle to the
engine after the first call but the engine will not post any tasks to custom
task runners specified by the embedder till the
`FlutterEngineRunInitialized` call. Embedders can guard the Flutter engine
handle behind a mutex for safe task runner interop.
* `FlutterEngineShutdown` can be preceded by the `FlutterEngineDeinitialize`
call. After this call the Flutter engine will no longer post tasks onto
embedder managed task runners. It is still embedder responsibility to
collect the Flutter engine handle via `FlutterEngineShutdown`.
* To maintain backwards compatibility with the old APIs, `FlutterEngineRun` is
now just a convenience for `FlutterEngineInitialize` and
`FlutterEngineRunInitilaized`. `FlutterEngineShutdown` now implicitly calls
`FlutterEngineDeinitialize` as well. This allows existing users who don't care
are custom task runner interop to keep using the old APIs.
* Adds complete test coverage for both old and new paths.
Fixes https://github.com/flutter/flutter/issues/42460
Prerequisite for https://github.com/flutter/flutter/issues/17579
The earlier design speculated that embedders could affect the same
transformations on the layers post engine compositor presentation but before
final composition.
However, the linked issue points out that this design is not suitable for use
with hardware overlay planes. When rendering to the same, to affect the
transformation before composition, embedders would have to render to an
off-screen render target and then apply the transformation before presentation.
This patch negates the need for that off-screen render pass.
To be clear, the previous architecture is still fully viable. Embedders still
have full control over layer transformations before composition. This is an
optimization for the hardware overlay planes use-case.
Fixes b/139758641
This patch allows embedders to split the Flutter layer tree into multiple
chunks. These chunks are meant to be composed one on top of another. This gives
embedders a chance to interleave their own contents between these chunks.
The Flutter embedder API already provides hooks for the specification of
textures for the Flutter engine to compose within its own hierarchy (for camera
feeds, video, etc..). However, not all embedders can render the contents of such
sources into textures the Flutter engine can accept. Moreover, this composition
model may have overheads that are non-trivial for certain use cases. In such
cases, the embedder may choose to specify multiple render target for Flutter to
render into instead of just one.
The use of this API allows embedders to perform composition very similar to the
iOS embedder. This composition model is used on that platform for the embedding
of UIKit view such and web view and map views within the Flutter hierarchy.
However, do note that iOS also has threading configurations that are currently
not available to custom embedders.
The embedder API updates in this patch are ABI stable and existing embedders
will continue to work are normal. For embedders that want to enable this
composition mode, the API is designed to make it easy to opt into the same in an
incremental manner.
Rendering of contents into the “root” rendering surface remains unchanged.
However, now the application can push “platform views” via a scene builder.
These platform views need to handled by a FlutterCompositor specified in a new
field at the end of the FlutterProjectArgs struct.
When a new platform view in introduced within the layer tree, the compositor
will ask the embedder to create a new render target for that platform view.
Render targets can currently be OpenGL framebuffers, OpenGL textures or software
buffers. The type of the render target returned by the embedder must be
compatible with the root render surface. That is, if the root render surface is
an OpenGL framebuffer, the render target for each platform view must either be a
texture or a framebuffer in the same OpenGL context. New render target types as
well as root renderers for newer APIs like Metal & Vulkan can and will be added
in the future. The addition of these APIs will be done in an ABI & API stable
manner.
As Flutter renders frames, it gives the embedder a callback with information
about the position of the various platform views in the effective hierarchy.
The embedder is then meant to put the contents of the render targets that it
setup and had previously given to the engine onto the screen (of course
interleaving the contents of the platform views).
Unit-tests have been added that test not only the structure and properties of
layer hierarchy given to the compositor, but also the contents of the texels
rendered by a test compositor using both the OpenGL and software rendering
backends.
Fixes b/132812775
Fixesflutter/flutter#35410
This exposes the `Settings::leak_vm` flag to custom embedders. All embedder
unit-tests now shut down the VM on the shutdown of the last engine in the
process. The mechanics of VM shutdown are already tested in the Shell unit-tests
harness in the DartLifecycleUnittests set of of assertions. This just exposes
that functionality to custom embedders. Since it is part of the public stable
API, I also switched the name of the field to be something less snarky than the
field in private shell settings.
embedder.h is a C API, so has no namespace, and only uses 'Flutter' as a
prefix for most symbol names. This creates potential collisions with
other code; for instance, FlutterEngine is the name of a type in
embedder.h, but also an ObjC class in the iOS Flutter API.
This adds a macro that can be set to prefix symbol names, allowing
clients (notably, the macOS embedding) to adjust the names used by the
embedding API internally without breaking ABI or API compatibility for
the standard engine build.
Currently the macro is only applied to FlutterEngine, since that's the
symbol that is currently at issue, but it can be expanded to other
symbols in the future.
Debug builds log invalid file errors on launch of anything using the
embedding API due to an unconditional use of assets_dir, even though
only one of assets_dir or assets_path needs to be set (and the embedding
API currently uses the latter). This checks that the FD has been set
before trying to use it to create an asset resolver.
Also eliminates a duplicate code path in embedder.cc, where it was
calling RunConfiguration::InferFromSettings, then running exactly the
same asset manager creation code again locally.
Messages sent to the embedder host may be one-way messages with no response
handler. If the host calls FlutterEngineSendPlatformMessageResponse on a
one-way message, then just delete the message response handle.
Also update the documentation to indicate that
FlutterEngineSendPlatformMessageResponse must be called for all messages.
Previously the docs implied that some FlutterPlatformMessage objects may
have a null response_handle. The embedder will now set a response_handle for
every message (even if the sender does not expect a response).
Currently, all our host unit-tests that have rendering concerns use the software backend because of OpenGL ES availability and stability issues on the various platforms where we run host tests. Unfortunately, entire subsystems are disabled (and not tested) when rendering with the software backend. This patch pulls in SwiftShader and via pending patches in the buildroot, configures the host unit-tests to optionally use OpenGL ES in a stable manner without relying on the OpenGL drivers being present (and functional).
I have wired up the embedder test fixture in this patch to use the SwiftShader based OpenGL ES driver. I will update the shell and runtime unittests in a subsequent patch as well. The on and offscreen surfaces are configured as 1x1 pbuffer surface because we should be able to write pixel tests using OpenGL directly wihout having to deal with surfaces.
Using it, a Flutter app can monitor missing frames in the release mode, and a custom Flutter runner (e.g., Fuchsia) can add a custom FrameRasterizedCallback.
Related issues:
https://github.com/flutter/flutter/issues/26154https://github.com/flutter/flutter/issues/31444https://github.com/flutter/flutter/issues/32447
Need review as soon as possible so we can merge this before the end of May to catch the milestone.
Tests added:
* NoNeedToReportTimingsByDefault
* NeedsReportTimingsIsSetWithCallback
* ReportTimingsIsCalled
* FrameRasterizedCallbackIsCalled
* FrameTimingSetsAndGetsProperly
* onReportTimings preserves callback zone
* FrameTiming.toString has the correct format
This will need a manual engine roll as the TestWindow defined in the framework needs to implement onReportTimings.
Corects a bnuch of typeos throughout teh engien codebsae. Also makes
a couple minor Commonwealth -> US spelling adjustments for consistency
with the rest of Flutter's codebase.
Made use of `misspell` tool:
https://github.com/client9/misspell
Rather than hard-coding the type of incoming events to mouse, and
synthesizing a primary button press for kDown/kUp, expose device kind
and buttons in the API.
For backwards compatibility, if the type is not set, the old behavior is
used. If an embedder sets the type to mouse explicitly, however, they
must also set correct button information.
For the touch type, the API abstracts away the framework's internal
expectation that a button is set for touch down/move for simplicity.
Fixesflutter/flutter#32854
If the mapping callback is not set or it the callback returns invalid data, ICU initialization will be embedder responsibility.
This affects all embedders and the following have been audited:
* Android: Via a symbol mapping.
* iOS: Via a file mapping.
* Embedder: Via a file mapping.
* Fuchsia: Via a VMO mapping
* Test shells and Flutter tester: Via file mapping with ICU data needing to be next to the executable.
Some components in the Flutter engine were derived from the forked blink codebase. While the forked components have either been removed or rewritten, the use of the blink namespace has mostly (and inconsistently) remained. This renames the blink namesapce to flutter for consistency. There are no functional changes in this patch.
Currently, all Flutter threads are managed by the engine itself. This works for
all threads except the platform thread. On this thread, the engine cannot see
the underlying event multiplexing mechanism. Using the new task runner
interfaces, the engine can relinquish the task of setting up the event
multiplexing mechanism and instead have the embedder provide one for it during
setup.
This scheme is only wired up for the platform thread. But, the eventual goal
is to expose this message loop interoperability for all threads.
This will allow us to easily visualize the time the platform informed the engine of a vsync event, its arguments, and when the engine began its UI thread workload using this information.
Some embedders may have to wait on fences asynchronously before committing
contents. This allows them to post a task onto the engine managed thread used
for rendering.
Some clients (e.g., embedded devices) prefer generating persistent cache files for the specific device beforehand, and ship them as readonly files in OTA packages.
Adds support for pointer signals, in a way that will support both discrete events (e.g., scroll wheels, flutter/flutter#22762) and continuous gestures (e.g., trackpad scroll, flutter/flutter#21953).
Also exposes these new event options to the embedder. Does not include code to send the
new events from the platform shells.
Previously the transformation matrix returned on semantics nodes was
fetched by matrix col,row (incorrectly). This uses the SkMatrix
constants instead and adds a test.
Some embedders prefer to minimise the number of semantics node/custom
action updates sent back to the host platform -- for example due to
expensive serialisation mechanisms, etc.
This patch provides a 'batch end' signal that provides embedders with an
indication of when a self-consistent set of semantics node or custom action
updates have been sent.
We overload the node/action ID with information that conveys a batch end
by using an ID (-1) that is never allotted to semantics nodes by the
framework.
Link dart:* sources into engine for debugger source support
Currently, dart:* libraries appear to have no source in
debuggers like Observatory. With this change, these sources will be
available in debug mode applications. Sources for dart:* libraries are
lazily loaded on a script-by-script basis.
Refer to https://dart-review.googlesource.com/c/sdk/+/93375 for the Dart
SDK change.
Flutter's accessibility APIs consist of three main calls from the
embedder to the Dart application:
1. FlutterEngineUpdateSemanticsEnabled: enables/disables semantics support.
2. FlutterEngineUpdateAccessibilityFeatures: sets embedder-specific
accessibility features.
3. FlutterEngineDispatchSemanticsAction: dispatches an action (tap,
long-press, scroll, etc.) to a semantics node.
and two main callbacks triggered by Dart code:
1. FlutterUpdateSemanticsNodeCallback: notifies the embedder of
updates to the properties of a given semantics node.
2. FlutterUpdateSemanticsCustomActionCallback: notifies the embedder
of updates to custom semantics actions registered in Dart code.
In the Flutter framework, when accessibility is first enabled, the
embedder will receive a stream of update callbacks notifying the
embedder of the full semantics tree. On further changes in the Dart
application, only updates will be sent.
Adds 'add', 'remove', and 'hover' to the set of pointer phases that are
available to embedders. This is necessary for them to send hover events
to the engine.
