add ability to attach callbacks when resolving file asset listeners

Bascially add tracking of fileAssetReferencers from file assets, so that when file assets update, they can tell things that reference them to update also.

its worth looking at the rive-flutter & runtime implementations

in cpp it looks like we can hook into the delete hooks nicely to clean up after ourselves (so that when artboards get collected we are not holding references to them from file assets)

in dart this is more of a problem, however using weakReferences we do end up seeing artboards go out of scope
but weakReferences requires us to bump to a min dart of 2.17 (we are 2.14 in flutter & 2.12 in our editor atm)

the update here also uses the referencers to mark fonts dirty when fonts are set, which causes them to be updated on the next draw cycle

(video showing font updates working properly now in dart)

(video showing how referencers get collected and trashed in dart, it looks like we hold onto about 10 of them at a time.. but they do drop off over time. also we start with 2 references, the main artboard and the artboard instance)

7bc216b03 add ability to attach callbacks when resolving file asset listeners (#6068)

Co-authored-by: Maxwell Talbot <>
15 files changed
tree: 75853b6d9308ba95e8656612a76f6f0ab8ef8549
  1. .github/
  2. .vscode/
  3. build/
  4. cg_renderer/
  5. decoders/
  6. dependencies/
  7. dev/
  8. include/
  9. rivinfo/
  10. skia/
  11. src/
  12. tess/
  13. test/
  14. utils/
  15. vello/
  16. viewer/
  17. .dockerignore
  18. .gitignore
  19. .lua-format
  20. .rive_head
  22. Dockerfile
  23. Doxyfile

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Rive C++ is a runtime library for Rive, a real-time interactive design and animation tool.

The C++ runtime for Rive provides these runtime features:

  • Loading Artboards and their contents from .riv files.
  • Querying LinearAnimations and StateMachines from Artboards.
  • Making changes to Artboard hierarchy (fundamentally same guts used by LinearAnimations and StateMachines) and effienclty solving those changes via Artboard::advance.
  • Abstract Renderer for submitting high level vector path commands with retained path objects to optimize and minimize path re-computation (ultimately up to the concrete rendering implementation).
  • Example concrete renderer written in C++ with Skia. Skia renderer code is in skia/renderer/src/skia_renderer.cpp.

Build System

We use premake5. The Rive dev team primarily works on MacOS. There is some work done by the community to also support Windows and Linux. PRs welcomed for specific platforms you wish to support! We encourage you to use premake as it's highly extensible and configurable for a variety of platforms.


In the rive-cpp directory, run to debug build and release for a release build.

If you've put the premake5 executable in the rive-cpp/build folder, you can run it with PATH=.:$PATH ./

Rive makes use of clang vector builtins, which are, as of 2022, still a work in progress. Please use clang and ensure you have the latest version.

Building skia projects

cd skia/dependencies
./      // this will invoke

To build viewer (plus you'll needed CMake installed)



Uses the Catch2 testing framework.

cd dev

In the dev directory, run to compile and execute the tests.

(if you've installed premake5 in rive-cpp/build, you can run it with PATH=../../build:$PATH ./

The tests live in rive/test. To add new tests, create a new xxx_test.cpp file here. The test harness will automatically pick up the new file.

There's a VSCode command provided to run tests from the Tasks: Run Task command palette.

Code Formatting

rive-cpp uses clang-format, you can install it with brew on MacOS: brew install clang-format.

Memory Checks

Note that if you‘re on MacOS you’ll want to install valgrind, which is somewhat complicated these days. This is the easiest solution (please PR a better one when it becomes available).

brew tap LouisBrunner/valgrind
brew install --HEAD LouisBrunner/valgrind/valgrind

You can now run the all the tests through valgrind by running memory.

Disassembly Explorer

If you want to examine the generated assembly code per cpp file, install Disassembly Explorer in VSCode.

A disassemble task is provided to compile and preview the generated assembly. You can reach it via the Tasks: Run Task command palette or you can bind it to a shortcut by editing your VSCode keybindings.json:

        "key": "cmd+d",
        "command": "workbench.action.tasks.runTask",
        "args": "disassemble"