| commit | 48f4ed7b8253282c8853941e4851bbe428bbcad1 | [log] [tgz] |
|---|---|---|
| author | Tong Mu <dkwingsmt@users.noreply.github.com> | Fri Mar 07 18:39:09 2025 -0800 |
| committer | dart-internal-monorepo <dart-internal-monorepo@dart-ci-internal.iam.gserviceaccount.com> | Fri Mar 07 19:19:30 2025 -0800 |
| tree | d260e17bb42a84077b5917931c04cc571aa652a9 | |
| parent | 6dcc200adf1af9913d603672bd810fd6fddf20cb [diff] |
RoundSuperellipse algorithm v3: Ultrawideband heuristic formula (#164755) This PR revises the algorithm for RoundSuperellipses, replacing the current "max ratio" approximation with an algorithm that works for ratios from 2.0 to infinity. The previous "max ratio" approximation, which replaces the middle of edges with straight lines when the ratio is above 2.3, turns out to produce results too close to classic RRects. After reexamining the shapes and more calculation, I discovered that the max-ratio approximation is flawed. Even squircles with with really high ratios (~100) have a significant part of the edges that must not be approximated by straight lines. The new version is much closer to native. ### Comparison Native: (Notice the long wedgy gap at the end of curves) <img src="https://github.com/user-attachments/assets/61b60191-7d45-4c49-9e09-b0422243cd8c" width="400"/> Before PR: (Notice the short wedgy gap at the end of curves) <img src="https://github.com/user-attachments/assets/15ea374b-4b16-4187-aaa4-94f432fbb61e" width="400"/> After PR: <img src="https://github.com/user-attachments/assets/973ef4d1-7c26-44a9-b45e-10d109d5618b" width="400"/> Another example (after PR). Even though the rectangular RSE has ratios of around 4, there are still curvature near the middle section of edges, which can be identified with the help of antialias pixels. <img width="838" alt="image" src="https://github.com/user-attachments/assets/5078d098-c582-48a8-81e5-615909def675" /> ### Details I found that `n` has really good linearity towards larger ratios. <img width="844" alt="image" src="https://github.com/user-attachments/assets/73e99e45-a0f0-450b-8e2b-f6fd97082958" /> I also found a good candidate for the precomputed unknown (called `k_xJ`), which has a smooth curve at the beginning and almost straight line towards larger `n`, removing the need to cap the scope of application of the formula. <img width="1203" alt="image" src="https://github.com/user-attachments/assets/67664898-2dbd-4f00-a9ba-d76030cf3742" /> The algorithm for paths are also updated in a similar way and approximated the Bezier factors with heuristic formulae for bigger `n`s. I've also verified that the path deviates from the geometry by no more than 0.01% over the range of n [15, 100] Theoretically removing "stretch" should simplify the algorithms. Unfortunately I had to spend more lines to process cases of zero radii, which were conveniently handled by stretches. ## Pre-launch Checklist - [ ] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [ ] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [ ] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [ ] I signed the [CLA]. - [ ] I listed at least one issue that this PR fixes in the description above. - [ ] I updated/added relevant documentation (doc comments with `///`). - [ ] I added new tests to check the change I am making, or this PR is [test-exempt]. - [ ] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [ ] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. <!-- Links --> [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md https://dart.googlesource.com/external/github.com/flutter/flutter/+/83781ae65c67f81cf16ce15209788fb3e5d00060
Monorepo is:
With depot_tools installed and on your path, create a directory for your monorepo checkout and run these commands to create a gclient solution in that directory:
mkdir monorepo cd monorepo gclient config --unmanaged https://dart.googlesource.com/monorepo gclient sync -D
This gives you a checkout in the monorepo directory that contains:
monorepo/ DEPS - the DEPS used for this gclient checkout commits.json - the pinned commits for Dart, flutter/engine, and flutter/flutter tools/ - scripts used to create monorepo DEPS engine/src/ - the flutter/buildroot repo flutter/ - the flutter/engine repo out/ - the build directory, where Flutter engine builds are created third_party/ - Flutter dependencies checked out by DEPS dart/ - the Dart SDK checkout. third_party - Dart dependencies, also used by Flutter flutter/ - the flutter/flutter repo
Flutter's instructions for building the engine are at Compiling the engine
They can be followed closely, with a few changes:
goma_ctl ensure_start is sufficient.Example build commands that work on linux:
MONOREPO_PATH=$PWD if [[ ! $PATH =~ (^|:)$MONOREPO_PATH/flutter/bin(:|$) ]]; then PATH=$MONOREPO_PATH/flutter/bin:$PATH fi export GOMA_DIR=$(dirname $(command -v gclient))/.cipd_bin goma_ctl ensure_start pushd engine/src flutter/tools/gn --goma --no-prebuilt-dart-sdk --unoptimized --full-dart-sdk autoninja -C out/host_debug_unopt popd
The Flutter commands used to build and run apps will use the locally built Flutter engine and Dart SDK, instead of the one downloaded by the Flutter tool, if the --local-engine option is provided.
For example, to build and run the Flutter spinning square sample on the web platform,
MONOREPO_PATH=$PWD cd flutter/examples/layers flutter --local-engine=host_debug_unopt \ -d chrome run widgets/spinning_square.dart cd $MONOREPO_PATH
To build for desktop, specify the desktop platform device in flutter run as -d macos or -d linux or -d windows. You may also need to run the command
flutter create --platforms=windows,macos,linux
on existing apps, such as sample apps. New apps created with flutter create already include these support files. Details of desktop support are at Desktop Support for Flutter
Tests in the Flutter source tree can be run with the flutter test command, run in the directory of a package containing tests. For example:
MONOREPO_PATH=$PWD cd flutter/packages/flutter flutter test --local-engine=host_debug_unopt cd $MONOREPO_PATH
Please file an issue or email the dart-engprod team with any problems with or questions about using monorepo.
We will update this documentation to address them.
flutter commands may download the engine and Dart SDK files for the configured channel, even though they will be using the local engine and its SDK.gclient sync needs to be run in an administrator session, because some installed dependencies create symlinks.