ai-box/cxx/cv/node.cc

#include <iostream>
#include <functional>
#include <opencv2/opencv.hpp>
#include "node.h"

using namespace Napi;

#define MAT_INSTANCE_METHOD(method) InstanceMethod<&CVMat::method>(#method, static_cast<napi_property_attributes>(napi_writable | napi_configurable))

static FunctionReference *constructor = nullptr;

class CVMat : public ObjectWrap<CVMat> {
  public:
	static Napi::Object Init(Napi::Env env, Napi::Object exports)
	{
		Function func = DefineClass(env, "Mat", {
													MAT_INSTANCE_METHOD(IsEmpty),
													MAT_INSTANCE_METHOD(GetCols),
													MAT_INSTANCE_METHOD(GetRows),
													MAT_INSTANCE_METHOD(GetChannels),
													MAT_INSTANCE_METHOD(Resize),
													MAT_INSTANCE_METHOD(Crop),
													MAT_INSTANCE_METHOD(Rotate),
													MAT_INSTANCE_METHOD(Clone),

													MAT_INSTANCE_METHOD(DrawCircle),

													MAT_INSTANCE_METHOD(Data),
													MAT_INSTANCE_METHOD(Encode),
												});
		constructor = new FunctionReference();
		*constructor = Napi::Persistent(func);
		exports.Set("Mat", func);
		env.SetInstanceData<FunctionReference>(constructor);
		return exports;
	}

	CVMat(const CallbackInfo &info)
		: ObjectWrap<CVMat>(info)
	{
		int mode = cv::IMREAD_COLOR_BGR;
		if (info.Length() > 1 && info[1].IsObject()) {
			Object options = info[1].As<Object>();
			if (options.Has("mode") && options.Get("mode").IsNumber()) mode = options.Get("mode").As<Number>().Int32Value();
		}

		if (info[0].IsString()) im_ = cv::imread(info[0].As<String>().Utf8Value(), mode);
		else if (info[0].IsTypedArray()) {
			auto buffer = info[0].As<TypedArray>().ArrayBuffer();
			uint8_t *bufferPtr = static_cast<uint8_t *>(buffer.Data());
			std::vector<uint8_t> data(bufferPtr, bufferPtr + buffer.ByteLength());
			im_ = cv::imdecode(data, mode);
		}
	}

	~CVMat() { im_.release(); }

	Napi::Value IsEmpty(const Napi::CallbackInfo &info) { return Boolean::New(info.Env(), im_.empty()); }
	Napi::Value GetCols(const Napi::CallbackInfo &info) { return Number::New(info.Env(), im_.cols); }
	Napi::Value GetRows(const Napi::CallbackInfo &info) { return Number::New(info.Env(), im_.rows); }
	Napi::Value GetChannels(const Napi::CallbackInfo &info) { return Number::New(info.Env(), im_.channels()); }
	Napi::Value Resize(const Napi::CallbackInfo &info)
	{
		return CreateMat(info.Env(), [this, &info](auto &mat) { cv::resize(im_, mat.im_, cv::Size(info[0].As<Number>().Int32Value(), info[1].As<Number>().Int32Value())); });
	}
	Napi::Value Crop(const Napi::CallbackInfo &info)
	{
		return CreateMat(info.Env(), [this, &info](auto &mat) {
			mat.im_ = im_(cv::Rect(
				info[0].As<Number>().Int32Value(), info[1].As<Number>().Int32Value(),
				info[2].As<Number>().Int32Value(), info[3].As<Number>().Int32Value()));
		});
	}
	Napi::Value Rotate(const Napi::CallbackInfo &info)
	{
		return CreateMat(info.Env(), [this, &info](auto &mat) {
			auto x = info[0].As<Number>().DoubleValue();
			auto y = info[1].As<Number>().DoubleValue();
			auto angle = info[2].As<Number>().DoubleValue();
			cv::Mat rotation_matix = cv::getRotationMatrix2D(cv::Point2f(x, y), angle, 1.0);
			cv::warpAffine(im_, mat.im_, rotation_matix, im_.size());
		});
	}

	Napi::Value Clone(const Napi::CallbackInfo &info)
	{
		return CreateMat(info.Env(), [this, &info](auto &mat) { mat.im_ = im_.clone(); });
	}

	Napi::Value DrawCircle(const Napi::CallbackInfo &info)
	{
		int x = info[0].As<Number>().Int32Value();
		int y = info[1].As<Number>().Int32Value();
		int radius = info[2].As<Number>().Int32Value();
		int b = info[3].As<Number>().Int32Value();
		int g = info[4].As<Number>().Int32Value();
		int r = info[5].As<Number>().Int32Value();
		int thickness = info[6].As<Number>().Int32Value();
		int lineType = info[7].As<Number>().Int32Value();
		int shift = info[8].As<Number>().Int32Value();

		cv::circle(im_, cv::Point(x, y), radius, cv::Scalar(b, g, r), thickness, lineType, shift);
		return info.Env().Undefined();
	}

	Napi::Value Data(const Napi::CallbackInfo &info) { return ArrayBuffer::New(info.Env(), im_.ptr(), im_.elemSize() * im_.total()); }
	Napi::Value Encode(const Napi::CallbackInfo &info)
	{
		auto options = info[0].As<Object>();
		auto extname = options.Get("extname").As<String>().Utf8Value();
		cv::imencode(extname, im_, encoded_);
		return ArrayBuffer::New(info.Env(), encoded_.data(), encoded_.size());
	}


  private:
	inline Napi::Object EmptyMat(Napi::Env env) { return constructor->New({}).As<Object>(); }
	inline CVMat &GetMat(Napi::Object obj) { return *ObjectWrap<CVMat>::Unwrap(obj); }
	inline Napi::Object CreateMat(Napi::Env env, std::function<void(CVMat &mat)> callback)
	{
		auto obj = EmptyMat(env);
		callback(GetMat(obj));
		return obj;
	}

  private:
	cv::Mat im_;
	std::vector<uint8_t> encoded_;
};


void InstallOpenCVAPI(Env env, Object exports)
{
	CVMat::Init(env, exports);
}

#ifdef USE_OPENCV
static Object Init(Env env, Object exports)
{
	InstallOpenCVAPI(env, exports);
	return exports;
}
NODE_API_MODULE(addon, Init)

#endif