This repo is used to host and serve static assets in support of docs.flutter.dev, as well as some manual tests that use specially-crafted graphics.

Assets committed to this repo and pushed to GitHub are immediately available for linking and reference.

Reference the assets with this URL structure:

https://flutter.github.io/assets-for-api-docs/assets/<library>/<asset>

For example, an image named app_bar.png about AppBar from the material library would go in the assets/material/ directory and be at https://flutter.github.io/assets-for-api-docs/assets/material/app_bar.png.

All asset files should be under the assets directory in an appropriate subdirectory.

Images must be code-generated.

To create new images, see the packages/diagrams/lib/src/ directory.

The generate.dart script regenerates almost all of existing assets using the Flutter version you have installed. A small wrapper bin/generate.sh is provided as a convenience.

To limit image generation to certain categories and/or names, run:

# Filter by category
bin/generate.sh -c cupertino,material
# Filter by name
bin/generate.sh -n basic_material_app,blend_mode

bin/generate.sh --help lists available arguments.

The generate.dart script only works on macOS and Linux, because of the supporting apps it needs to run.

To optimize PNG files, it needs optipng, which is available for macOS via Homebrew, and Linux via apt-get.

To convert animations into mp4 files, it needs ffmpeg, available for macOS via Homebrew and Linux via apt-get.

flutter, dart (and when using an Android device, adb) commands need to be available in a directory in the PATH environment variable. (e.g. PATH=/<path_to_flutter>/flutter/bin/cache/dart-sdk/bin:/Android/Sdk/platform-tools:$PATH)

When using an Android device, be sure that the adb command is the same as the one running as a server (which is often started by your IDE, so use the same adb the IDE is running).

Please consider optimization tools for assets.

For PNGs, we recommend optipng, using the following command line:

optipng -zc1-9 -zm1-9 -zs0-3 -f0-5 *.png

Be careful about applying this aggressively. In particular, files in the assets/tests directory should not be optimized.

The automatic generation tool will automatically apply optimization to the assets it generates.

To create a new diagram:

1. Add a new file to packages/diagrams/lib/src/, and put the tests in there.

2. Export that file from packages/diagrams/lib/diagrams.dart.

3. Add your new class to the list in assets-for-api-docs/utils/diagram_generator/lib/main.dart.

4. Run generate.sh --name xxx where 'xxx' is the name of your diagram.

• /assets/videos/bee.mp4: CC0 Creative Commons, from https://pixabay.com/en/videos/honey-bee-insect-bee-flower-flying-211/
• /assets/videos/butterfly.mp4: CC0 Creative Commons, from https://pixabay.com/en/videos/butterfly-flower-insect-nature-209/
• Also see the license information for images used in the diagrams