dartcv #

OpenCV Bindings for Dart Language.

Important

The minimum required dart sdk version is 3.10 (Flutter 3.38) that supports hooks (Native-Assets).

Note

WIP, contributions are welcome!

dartcv

Example #

example

Supported Platforms #

Platform	Supported	Tested	Prebuilt Binaries
Android	✅	✅	x86_64, arm64-v8a, armeabi-v7a
iOS	✅	✅	arm64, x64+arm64(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	❌	❌
quality	✅	✅
freetype	✅	✅

❌ : not finished
☑️ : partially supported
✅ : finished
modules not in the above table are not considered, contributions are welcome
VideoIO and HighGUI modules dynamically linked FFMPEG, you should be careful with the license, this project takes no responsibility for the license.

Usage #

Pure Dart

import 'package:dartcv4/dartcv.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);
}

Asynchronous

import 'package:dartcv4/dartcv.dart' as cv;
import 'dart:async';
void main() async {
  final img = await cv.imreadAsync("test/images/lenna.png", flags: cv.IMREAD_COLOR);
  final gray = await cv.cvtColorAsync(img, cv.COLOR_BGR2GRAY);
  print("${img.rows}, ${img.cols}");

  await cv.imwriteAsync("test_cvtcolor.png", gray);
}

Flutter

see example

~~More examples are on the way...~~ see awesome-opencv_dart and share yours

Configure hooks options

dartcv4 now supports hooks options, you can configure it in pubspec.yaml

hooks:
  user_defines:
    dartcv4:
      # debug: true
      # treeshake: true # tree-shaking unused symbols, onyl works in AOT mode and Dart 3.13+.
      include_modules: # `core` is always included
        - imgcodecs
        - imgproc
        # ...
      exclude_modules:
        - contrib
        - dnn
        # ...
      # whether to build OpenCV with OpenCL support, per platform
      windows:
        use_opencl: false
      linux:
        use_opencl: true

debug: enable debug mode, default is false, if enabled, all messages will be printed to stderr.
treeshake: enable linker dead-code elimination, default is false. When enabled, the native library is compiled with function-level sections and the linker garbage-collects code that is not reachable from the exported symbols.
use_opencl: whether to build OpenCV with OpenCL support, default is false for all platforms. It can be configured per platform under a platform key (windows, linux, macos, android, ios). OpenCL is always disabled on ios since iOS does not support it. Enabling OpenCL may accelerate some operations (e.g. dnn), but it is disabled by default because the OpenCV OpenCL runtime can cause a racy hang-at-exit during process teardown; enable it only if you need the acceleration.
valid modules:
- core: always included
- included by default:
  - imgproc
  - imgcodecs
- excluded by default:
  - calib3d
  - features2d
  - flann
  - dnn
  - freetype
  - highgui
  - video
  - videoio
  - objdetect
  - photo
  - stitching
  - aruco
  - img_hash
  - quality
  - wechat_qrcode
  - ximgproc
  - xobjdetect
Note: even a module is excluded, it's dart code is still available, but throws a symbol not found exception when called.
~~videoio and highgui will introduce FFMPEG dynamic libraries (except for ios, ffmpeg is not supported on ios for now).~~ FFMPEG is no longer available with dartcv >= 2.2.0