opencv_dart 2.0.0-dev.3

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

opencv_dart

OpenCV Bindings for Dart Language.

Important

v2.x is prepared for Native Assets, Use only if you know what you are doing!

Note

WIP, contributions are welcome!

• opencv_dart
  • Example
  • Supported Platforms
  • Status
    • Core Modules
    • Contrib Modules
    • Usage
      • Pure Dart
      • Flutter
    • TODO
  • For Developers
    • How to compile manually with conan
  • Acknowledgement
  • Star History
  • License

Example

Supported Platforms

Platform	Supported	Tested	Prebuilt Binaries
Android	✅	☑️	x86_64, arm64-v8a, armeabi-v7a
iOS	✅	☑️	arm64, x64(Simulator)
Linux	✅	✅	x64
Windows	✅	✅	x64
macOS	✅	✅	x64, arm64

Status

Core Modules

module	Binding status	Test status	description
core	✅	✅	Core module
calib3d	✅	✅	Calib3D module
dnn	✅	✅	DNN module
features2d	✅	✅	Features2D module
gapi	❌	❌	GAPI module
highgui	✅	✅	HighGUI module
imgcodecs	✅	✅	ImageCodecs module
imgproc	✅	✅	ImageProc module
ml	❌	❌	ML module
objdetect	✅	✅	Object Detection module
photo	✅	✅	Photo module
stitching	☑️	☑️	Stitching module
svd	✅	✅	SVD module
video	✅	✅	Video module
videoio	✅	✅	VideoIO module

Contrib Modules

module	Binding status	Test status	description
aruco	✅	✅	ArUco module
img_hash	✅	✅	Image hashing module
cuda	❌	❌
wechat_qrcode	✅	✅
bgsegm	❌	❌
superres	❌	❌
xfeatures2d	❌	❌
ximgproc	❌	❌
xobjdetect	❌	❌
xphoto	❌	❌

• ❌ : not finished
• ☑️ : partially supported
• ✅ : finished
• modules not in the above table are not considered, contributions are welcome

Usage

Pure Dart

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

void main() {
  final img = cv.imread("test/images/lenna.png", flags: cv.IMREAD_COLOR);
  final gray = cv.cvtColor(img, gray, cv.COLOR_BGR2GRAY);
  print("${img.rows}, ${img.cols}");

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

Flutter

see example

More examples are on the way...

TODO

• ✅ compile libs for android, linux
• ✅ support for iOS, macOS
• ❌ add more examples
• ❌ documentation
• ✅ modify C wrapper to catch exceptions
• ✅ Native Assets
• ❌ async?
• ❌ more/full test coverage
• ✅ directly include opencv source code, refactor cmakelists.txt

For Developers

NOTE: since v1.0.1, to speed up compile in CI, opencv is precompiled in opencv.full, and this repo will download the prebuilt static libraries from it's release, if you want to compile entirely by yourself, you can compile opencv and explicitly set -o opencv_dir=<path to opencv> for the below commands or set OpenCV_DIR environment variable.

How to compile manually with conan

1. prepare a compiler.

   windows: Install Visual Studio 2019 or Later

   ubuntu: reference opencv official build guide to install

   sudo apt-get install build-essential libgtk-3-dev ffmpeg libavcodec-dev cmake \
      ninja-build ccache nasm libavformat-dev libavutil-dev libswscale-dev \
      libgflags-dev python3 libjpeg-dev libpng-dev libtiff-dev python3-pip
   

   macos:

   brew install --force --overwrite ninja ccache ffmpeg nasm cmake
   

   from v0.6.4, build system has been migrated to conan

      python3 -m pip install conan
      conan profile detect -f
   

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

3. cd opencv_dart

4. compile

   for windows:

   conan build . -b missing -s compiler.cppstd=20
   

   for linux, macos:

   conan build . -b missing
   

   for android:

   conan build . -b missing -pr:h profiles/android-<arch> -c tools.android:ndk_path="<ABSOLUTE path for ndk>"
   

   for ios:

   echo "tools.cmake.cmaketoolchain:user_toolchain=[\"`pwd`/profiles/ios.toolchain.cmake\"]" >> profiles/ios-<arch>
   conan build . -b missing -pr:h profiles/ios-<arch>
   

5. 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

Star History

License

Apache-2.0 License