目录

Impeller rendering engine

目录

What is Impeller?

#

Impeller provides a new rendering runtime for Flutter. The Flutter team's believes this solves Flutter's early-onset jank issue. Impeller precompiles a smaller, simpler set of shaders at Engine-build time so they don't compile at runtime.

For a video introduction to Impeller, check out the following talk from Google I/O 2023.


Introducing Impeller, Flutter's new rendering engine

Impeller has the following objectives:

  • Predictable performance: Impeller compiles all shaders and reflection offline at build time. It builds all pipeline state objects upfront. The engine controls caching and caches explicitly.
  • Instrumentable: Impeller tags and labels all graphics resources, such as textures and buffers. It can capture and persist animations to disk without affecting per-frame rendering performance.
  • Portable: Flutter doesn't tie Impeller to a specific client-rendering API. You can author shaders once and convert them to backend-specific formats, as necessary.
  • Leverages modern graphics APIs: Impeller uses, but doesn't depend on, features available in modern APIs like Metal and Vulkan.
  • Leverages concurrency: Impeller can distribute single-frame workloads across multiple threads, if necessary.

Availability

#

Where can you use Impeller?

iOS

#

Flutter enables Impeller by default on iOS.

  • To disable Impeller on iOS when debugging, pass --no-enable-impeller to the flutter run command.

    flutter run --no-enable-impeller

  • To disable Impeller on iOS when deploying your app, add the following tags under the top-level <dict> tag in your app's Info.plist file.

    xml
      <key>FLTEnableImpeller</key>
  <false />

The team continues to improve iOS support. If you encounter performance or fidelity issues with Impeller on iOS, file an issue in the GitHub tracker. Prefix the issue title with [Impeller] and include a small reproducible test case.

macOS

#

As of the 3.19 release, you can try out Impeller for macOS behind a flag. In a future release, the ability to opt-out of using Impeller will be removed.

To enable Impeller on macOS when debugging, pass --enable-impeller to the flutter run command.

flutter run --enable-impeller

To enable Impeller on macOS when deploying your app, add the following tags under the top-level <dict> tag in your app's Info.plist file.

xml
  <key>FLTEnableImpeller</key>
  <true />

Android

#

As of the 3.22 release, Impeller on Android with Vulkan is a release candidate. On devices that don't support Vulkan, Impeller will fallback to the the legacy OpenGL renderer. No action on your part is necessary for this fallback behavior. Consider trying Impeller on Android before it becomes the default on stable, you can explicitly opt into it.

To try out Impeller on Vulkan-capable Android devices, pass --enable-impeller to flutter run:

flutter run --enable-impeller

Or, you can add the following setting to your project's AndroidManifest.xml file under the <application> tag:

xml
<meta-data
    android:name="io.flutter.embedding.android.EnableImpeller"
    android:value="true" />

Bugs and issues

#

For the full list of Impeller's known bugs and missing features, the most up-to-date information is on the Impeller project board on GitHub.

The team continues to improve Impeller support. If you encounter performance or fidelity issues with Impeller on any platform, file an issue in the GitHub tracker. Prefix the issue title with [Impeller] and include a small reproducible test case.

Please include the following information when submitting an issue for Impeller:

  • The device you are running on, including the chip information.
  • Screenshots or recordings of any visible issues.
  • An export of the performance trace. Zip the file and attach it to the GitHub issue.

Architecture

#

To learn more details about Impeller's design and architecture, check out the README.md file in the source tree.

Additional information

#

除非另有说明，本文档之所提及适用于 Flutter 的最新稳定版本，本页面最后更新时间: 2024-07-06。 查看文档源码 或者 为本页面内容提出建议。