opencv_dart #

OpenCV Bindings for Dart Language.

!!!This package is experiment and APIs may change in the future!!!

Many tests unfinished, contributions are welcome!

Prebuilt binaries for Android(arm64-v8a, armeabi-v7a, x86_64), Linux(x64) and Windows(x64) are available,for other platforms, you have to build them your self.

IMPORTANT #

After added to pubspec.yaml or install by commandline, please run dart run opencv_dart:setup -p <platform> -a <arch> to download prebuilt binaries.

• platform: auto android linux windows
• arch: auto x86 x64 x86_64(android only) arm64-v8a(android only) armeabi-v7a(android only)

Please use v0.3.0 and later version.

Status #

• ❌ : not finished
• ☑️ : almost finished
• ✅ : finished
• videoio: cv.VideoCapture from file is not supported yet supported now.

Usage #

import 'package:opencv_dart/opencv_dart.dart' as cv;

final img = cv.imread("test/images/lenna.png", flags: cv.IMREAD_COLOR);
final gray = cv.Mat.empty();

cv.cvtColor(img, gray, cv.COLOR_BGR2GRAY);
print("${img.rows}, ${img.cols}");

cv.imwrite("test_cvtcolor.png", gray);

More examples are on the way...

TODO #

• ✅ compile libs for android, linux
• ❌ support for iOS, macOS
• ❌ add more examples
• ❌ modify C wrapper to catch exceptions
• ❌ Native Assets
• ❌ async?

For Developers #

This package is in heavy development, dynamic libraries for Windows and linux have been compiled, for other platforms, you need to compile it yourself.

How to compile #

1. prepare a compiler.

   windows: Install Visual Studio 2019 or Later

   ubuntu: reference opencv official build guide to install

2. install dependencies: cmake, python, add to PATH

3. clone this repo, git clone https://github.com/rainyl/opencv_dart.git

4. cd opencv_dart and git submodule update --init

5. compile opencv

   for windows:

   python .\scripts\build.py --opencv --os linux --arch x64 --build-dir build --src src
   

   for linux:

   python ./scripts/build.py --opencv --os linux --arch x64 --build-dir build --src src
   

   for android, you need to download android ndk and opencv for android sdk, extract opencv sdk and copy and rename OpenCV-android-sdk to build/android directory.

6. compile this package along with gocv, windows: ./scripts/build.ps1, linux: ./scripts/build.sh, this will generate libopencv_dart.dll or libopencv_dart.so

7. copy libs to corresponding platform directorys, i.e., libopencv_dart.dll to windows, libopencv_dart.so to linux. this is necessary for dart and flutter to load the dynamic library.

8. If you want to test using vscode, add dynamic library path to "dart.env" in settings.json

Acknowledgement #

• gocv project: https://github.com/hybridgroup/gocv License: Apache-2.0

License #

Apache-2.0 License