assets-for-api-docs

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.

URL structure

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.

Generation

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 (bin\generate.bat on Windows) is provided as a convenience.

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

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

bin/generate --help lists available arguments.

Prerequisites

The generate.dart script works on macOS, Linux, and Windows, but it needs several prerequisites in order to run. On Linux and macOS run bin/generate. On Windows, run bin\generate.bat.

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

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

Both optipng and ffmpeg need to be in your path when you run the generate script.

flutter, dart (and when using an Android device, adb) commands also 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).

You cannot currently generate docs on an iOS device (although you can generate them on macOS).

Optimization

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.

Creating new diagrams

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 bin/generate --name xxx where 'xxx' is the name of your diagram.

Origin of third-party content

• /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