node-opencv/src/VideoCaptureWrap.cc

#include "VideoCaptureWrap.h"
#include "Matrix.h"
#include "OpenCV.h"

#include  <iostream>
using namespace std;

v8::Persistent<FunctionTemplate> VideoCaptureWrap::constructor;

struct videocapture_baton {

  Persistent<Function> cb;
  VideoCaptureWrap *vc;
  Matrix *im;

  uv_work_t request;
};

void VideoCaptureWrap::Init(Handle<Object> target) {
  NanScope();

  //Class
  Local<FunctionTemplate> ctor = NanNew<FunctionTemplate>(VideoCaptureWrap::New);
  NanAssignPersistent(constructor, ctor);
  ctor->InstanceTemplate()->SetInternalFieldCount(1);
  ctor->SetClassName(NanNew("VideoCapture"));

  // Prototype
  //Local<ObjectTemplate> proto = constructor->PrototypeTemplate();

  NODE_SET_PROTOTYPE_METHOD(ctor, "read", Read);
  NODE_SET_PROTOTYPE_METHOD(ctor, "setWidth", SetWidth);
  NODE_SET_PROTOTYPE_METHOD(ctor, "setHeight", SetHeight);
  NODE_SET_PROTOTYPE_METHOD(ctor, "setPosition", SetPosition);
  NODE_SET_PROTOTYPE_METHOD(ctor, "close", Close);
  NODE_SET_PROTOTYPE_METHOD(ctor, "ReadSync", ReadSync);
  NODE_SET_PROTOTYPE_METHOD(ctor, "grab", Grab);
  NODE_SET_PROTOTYPE_METHOD(ctor, "retrieve", Retrieve);

  target->Set(NanNew("VideoCapture"), ctor->GetFunction());
}

NAN_METHOD(VideoCaptureWrap::New) {
  NanScope();

  if (args.This()->InternalFieldCount() == 0)
  return NanThrowTypeError("Cannot Instantiate without new");

  VideoCaptureWrap *v;

  if (args[0]->IsNumber()) {
    v = new VideoCaptureWrap(args[0]->NumberValue());
  } else {
    //TODO - assumes that we have string, verify
    v = new VideoCaptureWrap(std::string(*NanAsciiString(args[0]->ToString())));
  }

  v->Wrap(args.This());

  NanReturnValue(args.This());
}

VideoCaptureWrap::VideoCaptureWrap(int device) {
  NanScope();
  cap.open(device);

  if(!cap.isOpened()) {
    NanThrowError("Camera could not be opened");
  }
}

VideoCaptureWrap::VideoCaptureWrap(const std::string& filename) {
  NanScope();
  cap.open(filename);
  // TODO! At the moment this only takes a full path - do relative too.
  if(!cap.isOpened()) {
    NanThrowError("Video file could not be opened (opencv reqs. non relative paths)");
  }
}

NAN_METHOD(VideoCaptureWrap::SetWidth) {
  NanScope();
  VideoCaptureWrap *v = ObjectWrap::Unwrap<VideoCaptureWrap>(args.This());

  if(args.Length() != 1)
  NanReturnUndefined();

  int w = args[0]->IntegerValue();

  if(v->cap.isOpened())
  v->cap.set(CV_CAP_PROP_FRAME_WIDTH, w);

  NanReturnUndefined();
}

NAN_METHOD(VideoCaptureWrap::SetHeight) {
  NanScope();
  VideoCaptureWrap *v = ObjectWrap::Unwrap<VideoCaptureWrap>(args.This());

  if(args.Length() != 1)
  NanReturnUndefined();

  int h = args[0]->IntegerValue();

  v->cap.set(CV_CAP_PROP_FRAME_HEIGHT, h);

  NanReturnUndefined();
}

NAN_METHOD(VideoCaptureWrap::SetPosition) {
  NanScope();
  VideoCaptureWrap *v = ObjectWrap::Unwrap<VideoCaptureWrap>(args.This());

  if(args.Length() != 1)
  NanReturnUndefined();

  int pos = args[0]->IntegerValue();

  v->cap.set(CV_CAP_PROP_POS_FRAMES, pos);

  NanReturnUndefined();
}

NAN_METHOD(VideoCaptureWrap::Close) {
  NanScope();
  VideoCaptureWrap *v = ObjectWrap::Unwrap<VideoCaptureWrap>(args.This());

  v->cap.release();

  NanReturnUndefined();
}

class AsyncVCWorker: public NanAsyncWorker {
public:
  AsyncVCWorker(NanCallback *callback, VideoCaptureWrap* vc,
  bool retrieve = false, int channel = 0) :
      NanAsyncWorker(callback),
      vc(vc),
      retrieve(retrieve),
      channel(channel) {
  }

  ~AsyncVCWorker() {
  }

  // Executed inside the worker-thread.
  // It is not safe to access V8, or V8 data structures
  // here, so everything we need for input and output
  // should go on `this`.
  void Execute() {
    if (retrieve) {
      if (!this->vc->cap.retrieve(mat, channel)) {
        SetErrorMessage("retrieve failed");
      }
      return;
    }
    this->vc->cap.read(mat);
  }

  // Executed when the async work is complete
  // this function will be run inside the main event loop
  // so it is safe to use V8 again
  void HandleOKCallback() {
    NanScope();

    Local<Object> im_to_return= NanNew(Matrix::constructor)->GetFunction()->NewInstance();
    Matrix *img = ObjectWrap::Unwrap<Matrix>(im_to_return);
    img->mat = mat;

    Local<Value> argv[] = {
      NanNull()
      , im_to_return
    };

    TryCatch try_catch;
    callback->Call(2, argv);
    if (try_catch.HasCaught()) {
      FatalException(try_catch);
    }
  }

private:
  VideoCaptureWrap *vc;
  cv::Mat mat;
  bool retrieve;
  int channel;
};

NAN_METHOD(VideoCaptureWrap::Read) {
  NanScope();
  VideoCaptureWrap *v = ObjectWrap::Unwrap<VideoCaptureWrap>(args.This());

  REQ_FUN_ARG(0, cb);

  NanCallback *callback = new NanCallback(cb.As<Function>());
  NanAsyncQueueWorker(new AsyncVCWorker(callback, v));

  NanReturnUndefined();
}

NAN_METHOD(VideoCaptureWrap::ReadSync) {
  NanScope();
  VideoCaptureWrap *v = ObjectWrap::Unwrap<VideoCaptureWrap>(args.This());

  Local<Object> im_to_return= NanNew(Matrix::constructor)->GetFunction()->NewInstance();
  Matrix *img = ObjectWrap::Unwrap<Matrix>(im_to_return);

  v->cap.read(img->mat);

  NanReturnValue(im_to_return);
}

class AsyncGrabWorker: public NanAsyncWorker {
public:
  AsyncGrabWorker(NanCallback *callback, VideoCaptureWrap* vc) :
      NanAsyncWorker(callback),
      vc(vc) {
  }

  ~AsyncGrabWorker() {
  }

  void Execute() {
    if (!this->vc->cap.grab()) {
      SetErrorMessage("grab failed");
    }
  }

private:
  VideoCaptureWrap *vc;
};

NAN_METHOD(VideoCaptureWrap::Grab) {
  NanScope();
  VideoCaptureWrap *v = ObjectWrap::Unwrap<VideoCaptureWrap>(args.This());

  REQ_FUN_ARG(0, cb);

  NanCallback *callback = new NanCallback(cb.As<Function>());
  NanAsyncQueueWorker(new AsyncGrabWorker(callback, v));

  NanReturnUndefined();
}

NAN_METHOD(VideoCaptureWrap::Retrieve) {
  NanScope();
  VideoCaptureWrap *v = ObjectWrap::Unwrap<VideoCaptureWrap>(args.This());

  int channel = 0;
  REQ_FUN_ARG(0, cb);
  INT_FROM_ARGS(channel, 1);

  NanCallback *callback = new NanCallback(cb.As<Function>());
  NanAsyncQueueWorker(new AsyncVCWorker(callback, v, true, channel));

  NanReturnUndefined();
}