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Description:

opencv dart

opencv_dart #
OpenCV Bindings for Dart Language. Support both asynchronous and synchronous!

Important
For v1.0.6 and later, libs will be downloaded from
Releases automatically.

If you want to setup manually, please set OPENCV_DART_DISABLE_AUTO_BUILD environment variable,
e.g., export OPENCV_DART_DISABLE_AUTO_BUILD=1(for Unix-like)
or $env:OPENCV_DART_DISABLE_AUTO_BUILD=1(for Windows)

For v1.0.4 and below, make sure run the following setup commands before running your app:

flutter pub add opencv_dart or dart pub add opencv_dart
dart run opencv_dart:setup <platform> --arch <arch>

platform
arch

android
x86_64 arm64-v8a armeabi-v7a

linux
x64

windows
x64

macos
x64 arm64

ios
os64 (universal framework)

More questions: refer to #212 or open new issues.
If you are using flutter with Native Assets feature supported, consider using v2.x version, see more in native-assets branch

Note
WIP, APIs may change in the future, contributions are welcome!

opencv_dart

Example
Supported Platforms
Status

Core Modules
Contrib Modules
Usage

Pure Dart
Flutter

TODO

For Developers

How to compile

1. Install dependencies
2. clone this repo
3. compile
4. test

Contributors
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
videoio: cv.VideoCapture from file is not supported yet supported now.

Usage #

Warning
Since v1.0.0, nearly ALL APIs were changed to compitable with opencv-python,
for example:
// old API
void cvtColor(Mat src, Mat dst, int code);
// new API
Mat cvtColor(Mat src, int code, {Mat? dst});

// then usage will be changed from:
cvtColor(src, dst, cv.COLOR_BGR2GRAY);
// to:
final dst = cvtColor(src, cv.COLOR_BGR2GRAY);
// or:
cvtColor(src, cv.COLOR_BGR2GRAY, dst: dst);
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If you really need updates for v0.6.x, open PRs and it will be merged to v0.6 branch.

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

cv.imwrite("test_cvtcolor.png", gray);
}
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Flutter
see example
More examples are on the way... see awesome-opencv_dart and share yours
TODO #

✅ compile libs for android, linux
✅ support for iOS, macOS
✅ add more examples
❌ documentation
✅ modify C wrapper to catch exceptions
✅ Native Assets, see native-assets branch
✅ 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 #
1. Install dependencies

Windows: Install Visual Studio 2019 or Later, install Conan
python3 -m pip install conan
conan profile detect -f
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If you are usin Scoop:
scoop install conan
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Linux: Ubuntu as example, note opencv.full is built on Ubuntu 22.04 with ffmpeg 4.4
sudo apt-get install build-essential libgtk-3-dev ffmpeg libavcodec-dev cmake \
ninja-build libavformat-dev libavutil-dev libswscale-dev \
libgflags-dev python3 libjpeg-dev libpng-dev libtiff-dev python3-pip

python3 -m pip install conan
conan profile detect -f
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macOS: XCode is required
brew install --force --overwrite ninja ffmpeg@6 conan
brew link --overwrite ffmpeg@6
conan profile detect -f
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2. clone this repo
git clone https://github.com/rainyl/opencv_dart.git
cd opencv_dart
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3. compile

Windows:
conan build . -b missing -s compiler.cppstd=20
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Linux, macos:
conan build . -b missing
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android

If you want to use your own NDK instead of conan maintained one, please set ANDROID_NDK_HOME
or ANDROID_NDK_ROOT environment variable, e.g., export ANDROID_NDK_HOME=/opt/android-ndk-r26c
conan build . -b missing -pr:h profiles/android-<arch> -c tools.android:ndk_path="<ABSOLUTE path for ndk>"
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ios:
conan build . -b missing -pr:h profiles/ios-<arch>
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4. test

Set OPENCV_DART_LIB_PATH environment variable to the path of the compiled dynamic library,
e.g., export OPENCV_DART_LIB_PATH=pwd/linux/libopencv_dart.so
or $ENV:OPENCV_DART_LIB_PATH=$PWD\windows\opencv_dart.dll
or append the lib path to the library search path of your system
If you want to test using vscode, add above variable to "dart.env" in settings.json

Contributors #

rainy liu

Abdelaziz Mahdy

爱因斯唐

JinWoo Jung

mdeleau

Matteo T.

Acknowledgement #

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

Star History #

License #
Apache-2.0 License