update data and tolist for mat

Author: rainyl

.pubignore

@@ -10,8 +10,8 @@ coverage/
 *.dylib
 *.lib
 pkgs/
-src/*.cpp
-src/*.h
+src/**/*.cpp
+src/**/*.h
 images/
 CMakeUserPresets*
 ffigen*

example/lib/main.dart

@@ -1,9 +1,8 @@
-import 'dart:async';
+import 'dart:isolate';
 import 'dart:typed_data';
 
-import 'package:camera_universal/camera_universal.dart';
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
-
 import 'package:opencv_dart/opencv_dart.dart' as cv;
 
 void main() {
@@ -19,57 +18,33 @@ class MyApp extends StatefulWidget {
 
 class _MyAppState extends State<MyApp> {
   var images = <Uint8List>[];
-  Uint8List? videoFrame;
-  CameraController cameraController = CameraController();
 
   @override
   void initState() {
     super.initState();
-    task();
-  }
-
-  Future<void> task() async {
-    await cameraController.initializeCameras();
-    await cameraController.initializeCamera(
-      setState: setState,
-    );
-    await cameraController.activateCamera(
-      setState: setState,
-      mounted: () {
-        return mounted;
-      },
-    );
-  }
-
-  void takePicture() async {
-    var frame = cv.Mat.empty();
-    if (cameraController.is_camera_init) {
-      final im = await cameraController.action_take_picture(
-          onCameraNotInit: () {},
-          onCameraNotSelect: () {},
-          onCameraNotActive: () {});
-      if (im != null) {
-        frame = cv.imread(im.path);
-      }
-    }
-    if (!frame.isEmpty) {
-      setState(() {
-        videoFrame = cv.imencode(cv.ImageFormat.png.ext, frame);
-      });
-    }
   }
 
   @override
   void dispose() {
-    cameraController.dispose();
     super.dispose();
   }
 
+  // native resources are unsendable for isolate, so use raw data or encoded Uint8List and convert back
+  Future<(Uint8List, Uint8List)> heavyTask(Uint8List buffer) async {
+    final ret = Isolate.run(() {
+      final im = cv.imdecode(Uint8List.fromList(buffer), cv.IMREAD_COLOR);
+      late cv.Mat gray, blur;
+      for (var i = 0; i < 1000; i++) {
+        gray = cv.cvtColor(im, cv.COLOR_BGR2GRAY);
+        blur = cv.gaussianBlur(im, (7, 7), 2, sigmaY: 2);
+      }
+      return (cv.imencode(cv.ImageFormat.png.ext, gray), cv.imencode(cv.ImageFormat.png.ext, blur));
+    });
+    return ret;
+  }
+
   @override
   Widget build(BuildContext context) {
-    const textStyle = TextStyle(fontSize: 25);
-    const spacerSmall = SizedBox(height: 10);
-
     return MaterialApp(
       home: Scaffold(
         appBar: AppBar(
@@ -79,50 +54,15 @@ class _MyAppState extends State<MyApp> {
           alignment: Alignment.center,
           child: Column(
             children: [
-              Expanded(
-                flex: 1,
-                child: Row(
-                  children: [
-                    Expanded(
-                      child: Camera(
-                        cameraController: cameraController,
-                        onCameraNotInit: (context) {
-                          return const SizedBox.shrink();
-                        },
-                        onCameraNotSelect: (context) {
-                          return const SizedBox.shrink();
-                        },
-                        onCameraNotActive: (context) {
-                          return const SizedBox.shrink();
-                        },
-                        onPlatformNotSupported: (context) {
-                          return const SizedBox.shrink();
-                        },
-                      ),
-                    ),
-                    Expanded(
-                        child: videoFrame == null
-                            ? Text("Empty")
-                            : Image.memory(videoFrame!))
-                  ],
-                ),
-              ),
               ElevatedButton(
                 onPressed: () async {
-                  final data = await DefaultAssetBundle.of(context)
-                      .load("images/lenna.png");
-                  final im =
-                      cv.imdecode(data.buffer.asUint8List(), cv.IMREAD_COLOR);
-                  final gray = cv.cvtColor(im, cv.COLOR_BGR2GRAY);
-                  final blur = cv.gaussianBlur(im, (7, 7), 2, sigmaY: 2);
+                  final data = await DefaultAssetBundle.of(context).load("images/lenna.png");
+                  final bytes = data.buffer.asUint8List();
+                  // heavy computation
+                  final (gray, blur) = await heavyTask(bytes);
                   setState(() {
-                    images = [
-                      data.buffer.asUint8List(),
-                      cv.imencode(cv.ImageFormat.png.ext, gray),
-                      cv.imencode(cv.ImageFormat.png.ext, blur)
-                    ];
+                    images = [bytes, gray, blur];
                   });
-                  takePicture();
                 },
                 child: const Text("Process"),
               ),

example/windows/runner/main.cpp

@@ -26,7 +26,7 @@ int APIENTRY wWinMain(_In_ HINSTANCE instance, _In_opt_ HINSTANCE prev,
 
   FlutterWindow window(project);
   Win32Window::Point origin(10, 10);
-  Win32Window::Size size(1280, 720);
+  Win32Window::Size size(541, 720);
   if (!window.Create(L"opencv_dart_example", origin, size)) {
     return EXIT_FAILURE;
   }

ffigen.yaml

@@ -53,10 +53,11 @@ headers:
     - src/stitching/stitching.h
     - src/video/video.h
     - src/video/videoio.h
-# functions:
-#   symbol-address:
-#     include:
-#       - ".*" # Do this to expose all function pointers.
+functions:
+  symbol-address:
+    include:
+      - "Mat_CloseVoid"
+      # - ".*" # Do this to expose all function pointers.
 #     exclude: # If you only use exclude, then everything not excluded is generated.
 #       - "dispose"
 

lib/src/core/array.dart

@@ -38,6 +38,11 @@ class U8Array extends NativeArray<ffi.Uint8, int> {
     return array;
   }
 
+  U8Array.fromPointer(ffi.Pointer<ffi.Uint8> ptr, int length) : super(length) {
+    this.ptr = ptr;
+    finalizer.attach(this, ptr);
+  }
+
   static final finalizer = Finalizer<ffi.Pointer<ffi.Uint8>>((p) => calloc.free(p));
 
   @override

lib/src/core/cv_vec.dart

@@ -7,6 +7,7 @@ import '../opencv.g.dart' as cvg;
 
 abstract class CvVec<T extends ffi.Struct> extends CvStruct<T> {
   CvVec.fromPointer(super.ptr) : super.fromPointer();
+  List<num> get val;
 }
 
 /// uchar

lib/src/core/exception.dart

@@ -29,18 +29,21 @@ class CvException implements Exception {
 
 void defaultCvErrorCallback(
   int code,
-  ffi.Pointer<ffi.Char> func_name,
-  ffi.Pointer<ffi.Char> err_msg,
-  ffi.Pointer<ffi.Char> file_name,
+  ffi.Pointer<ffi.Char> funcName,
+  ffi.Pointer<ffi.Char> errMsg,
+  ffi.Pointer<ffi.Char> fileName,
   int line,
   ffi.Pointer<ffi.Void> userdata,
 ) {
-  final err = err_msg.cast<Utf8>();
-  ;
-  final func = func_name.cast<Utf8>();
-  final file = file_name.cast<Utf8>();
-  print(
-      "OpenCV Native Error Occurred (code: $code, err: ${err.toDartString()}) in ${func.toDartString()} of file ${file.toDartString()}:$line");
+  final err = errMsg.cast<Utf8>();
+  final func = funcName.cast<Utf8>();
+  final file = fileName.cast<Utf8>();
+  final msg = "OpenCV Native Error Occurred ("
+      "code: $code, "
+      "err: ${err.toDartString()}) "
+      "func: ${func.toDartString()} "
+      "file: ${file.toDartString()}:$line";
+  print(msg);
   calloc.free(err);
   calloc.free(func);
   calloc.free(file);
@@ -54,9 +57,9 @@ void registerErrorCallback({cvg.DartErrorCallbackFunction? callback}) {
   CFFI.registerErrorCallback(fp.nativeFunction);
 }
 
-class OpenCvDartException implements Exception {
+class CvdException implements Exception {
   final String message;
-  OpenCvDartException(this.message);
+  CvdException(this.message);
 
   @override
   String toString() {