opencv_dart 0.4.0

OpenCV4 bindings for Dart language and Flutter, using dart:ffi. The most complete OpenCV bindings for Dart!

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

module	Binding status	Test status	description
aruco	✅	✅	ArUco module
core	✅	✅	Core module
features2d	✅	✅	Features2D module
highgui	✅	✅	HighGUI module
imgcodecs	✅	✅	ImageCodecs module
imgproc	✅	✅	ImageProc module
objdetect	✅	✅	Object Detection module
svd	✅	✅	SVD module
video	✅	✅	Video module
videoio	✅	✅	VideoIO module
asyncarray	❌	❌	AsyncArray module
calib3d	❌	❌	Calib3D module
dnn	❌	❌	DNN module
photo	✅	✅	Photo module
cuda	❌	❌	CUDA module
contrib	❌	❌	Contrib module

• ❌ : 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