Refactor to use combined create/open functions for VideoCapture and V…

…ideoWriter to simplify usage

Signed-off-by: deadprogram <[email protected]>

README.md

@@ -25,13 +25,12 @@ func main() {
 	deviceID := 0
 
 	// open webcam
-	webcam := opencv3.NewVideoCapture()
-	defer webcam.Close()
-
-	if ok := webcam.OpenDevice(deviceID); !ok {
-		fmt.Printf("error opening device: %v\n", deviceID)
+	webcam, err := opencv3.VideoCaptureDevice(int(deviceID))
+	if err != nil {
+		fmt.Printf("error opening video capture device: %v\n", deviceID)
 		return
-	}
+	}	
+	defer webcam.Close()
 
 	// open display window
 	window := opencv3.NewWindow("Face Detect")

examples/capture.go

@@ -18,12 +18,12 @@ import (
 
 func main() {
 	deviceID := 0
-	webcam := opencv3.NewVideoCapture()
-	defer webcam.Close()
-
-	if ok := webcam.OpenDevice(int(deviceID)); !ok {
-		fmt.Printf("error opening device: %v\n", deviceID)
+	webcam, err := opencv3.VideoCaptureDevice(int(deviceID))
+	if err != nil {
+		fmt.Printf("error opening video capture device: %v\n", deviceID)
+		return
 	}
+	defer webcam.Close()
 
 	// streaming, capture from webcam
 	buf := opencv3.NewMat()

examples/capwindow.go

@@ -19,13 +19,12 @@ import (
 
 func main() {
 	deviceID := 0
-	webcam := opencv3.NewVideoCapture()
-	defer webcam.Close()
-
-	if ok := webcam.OpenDevice(int(deviceID)); !ok {
-		fmt.Printf("error opening device: %v\n", deviceID)
+	webcam, err := opencv3.VideoCaptureDevice(int(deviceID))
+	if err != nil {
+		fmt.Printf("error opening video capture device: %v\n", deviceID)
 		return
 	}
+	defer webcam.Close()
 
 	window := opencv3.NewWindow("Capture")
 	defer window.Close()

examples/faceblur.go

@@ -33,13 +33,12 @@ func main() {
 	xmlFile := os.Args[2]
 
 	// open webcam
-	webcam := opencv3.NewVideoCapture()
-	defer webcam.Close()
-
-	if ok := webcam.OpenDevice(deviceID); !ok {
-		fmt.Printf("error opening device: %v\n", deviceID)
+	webcam, err := opencv3.VideoCaptureDevice(int(deviceID))
+	if err != nil {
+		fmt.Printf("error opening video capture device: %v\n", deviceID)
 		return
-	}
+	}	
+	defer webcam.Close()
 
 	// open display window
 	window := opencv3.NewWindow("Face Detect")

examples/facedetect.go

@@ -33,13 +33,12 @@ func main() {
 	xmlFile := os.Args[2]
 
 	// open webcam
-	webcam := opencv3.NewVideoCapture()
-	defer webcam.Close()
-
-	if ok := webcam.OpenDevice(deviceID); !ok {
-		fmt.Printf("error opening device: %v\n", deviceID)
+	webcam, err := opencv3.VideoCaptureDevice(int(deviceID))
+	if err != nil {
+		fmt.Printf("error opening video capture device: %v\n", deviceID)
 		return
-	}
+	}	
+	defer webcam.Close()
 
 	// open display window
 	window := opencv3.NewWindow("Face Detect")
@@ -78,10 +77,7 @@ func main() {
 			opencv3.Rectangle(img, r, blue)
 
 			size := opencv3.GetTextSize("Human", opencv3.FontHersheyPlain, 1.2, 2)
-			pt := image.Point{
-				X: r.X + (r.Width / 2) - (size.X / 2),
-				Y: r.Y - 2,
-			}
+			pt := image.Pt(r.Min.X + (r.Min.X / 2) - (size.X / 2), r.Min.Y - 2)
 			opencv3.PutText(img, "Human", pt, opencv3.FontHersheyPlain, 1.2, blue, 2)
 		}
 

examples/pvl/faceblur.go

@@ -33,13 +33,12 @@ func main() {
 	deviceID, _ := strconv.Atoi(os.Args[1])
 
 	// open webcam
-	webcam := opencv3.NewVideoCapture()
-	defer webcam.Close()
-
-	if ok := webcam.OpenDevice(deviceID); !ok {
-		fmt.Printf("error opening device: %v\n", deviceID)
+	webcam, err := opencv3.VideoCaptureDevice(int(deviceID))
+	if err != nil {
+		fmt.Printf("error opening video capture device: %v\n", deviceID)
 		return
-	}
+	}	
+	defer webcam.Close()
 
 	// open display window
 	window := opencv3.NewWindow("PVL Faceblur")

examples/pvl/smiledetect.go

@@ -35,13 +35,12 @@ func main() {
 	deviceID, _ := strconv.Atoi(os.Args[1])
 
 	// open webcam
-	webcam := opencv3.NewVideoCapture()
-	defer webcam.Close()
-
-	if ok := webcam.OpenDevice(deviceID); !ok {
-		fmt.Printf("error opening device: %v\n", deviceID)
+	webcam, err := opencv3.VideoCaptureDevice(int(deviceID))
+	if err != nil {
+		fmt.Printf("error opening video capture device: %v\n", deviceID)
 		return
-	}
+	}	
+	defer webcam.Close()
 
 	// open display window
 	window := opencv3.NewWindow("PVL Smile Detect")

examples/saveimage.go

@@ -30,13 +30,13 @@ func main() {
 	deviceID, _ := strconv.Atoi(os.Args[1])
 	saveFile := os.Args[2]
 
-	webcam := opencv3.NewVideoCapture()
+	webcam, err := opencv3.VideoCaptureDevice(int(deviceID))
+	if err != nil {
+		fmt.Printf("error opening video capture device: %v\n", deviceID)
+		return
+	}	
 	defer webcam.Close()
 
-	if ok := webcam.OpenDevice(deviceID); !ok {
-		fmt.Printf("error opening device: %v\n", deviceID)
-	}
-
 	img := opencv3.NewMat()
 	defer img.Close()
 

examples/savevideo.go

@@ -30,16 +30,13 @@ func main() {
 	deviceID, _ := strconv.Atoi(os.Args[1])
 	saveFile := os.Args[2]
 
-	webcam := opencv3.NewVideoCapture()
+	webcam, err := opencv3.VideoCaptureDevice(int(deviceID))
+	if err != nil {
+		fmt.Printf("error opening video capture device: %v\n", deviceID)
+		return
+	}	
 	defer webcam.Close()
 
-	writer := opencv3.NewVideoWriter()
-	defer writer.Close()
-
-	if ok := webcam.OpenDevice(deviceID); !ok {
-		fmt.Printf("error opening device: %v\n", deviceID)
-	}
-
 	img := opencv3.NewMat()
 	defer img.Close()
 
@@ -48,7 +45,12 @@ func main() {
 		return
 	}
 
-	writer.OpenWithMat(saveFile, 25, img)
+	writer, err := opencv3.VideoWriterFileMat(saveFile, 25, img)
+	if err != nil {
+		fmt.Printf("error opening video writer device: %v\n", saveFile)
+		return
+	}		
+	defer writer.Close()
 
 	for i := 0; i < 100; i++ {
 		if ok := webcam.Read(img); !ok {

pvl/README.md

@@ -18,13 +18,12 @@ func main() {
 	deviceID := 0
 
 	// open webcam
-	webcam := opencv3.NewVideoCapture()
-	defer webcam.Close()
-
-	if ok := webcam.OpenDevice(deviceID); !ok {
-		fmt.Printf("error opening device: %v\n", deviceID)
+	webcam, err := opencv3.VideoCaptureDevice(int(deviceID))
+	if err != nil {
+		fmt.Printf("error opening video capture device: %v\n", deviceID)
 		return
-	}
+	}	
+	defer webcam.Close()
 
 	// open display window
 	window := opencv3.NewWindow("PVL")

videoio.go

@@ -10,14 +10,27 @@ import (
 	"unsafe"
 )
 
-// VideoCapture is a bind of `cv::VideoCapture`.
+// VideoCapture is a wrapper around the cv::VideoCapture class.
 type VideoCapture struct {
 	p C.VideoCapture
 }
 
-// NewVideoCapture returns a new video capture.
-func NewVideoCapture() VideoCapture {
-	return VideoCapture{p: C.VideoCapture_New()}
+// VideoCaptureFile opens a VideoCapture from a file and prepares to start capturing
+func VideoCaptureFile(uri string) (vc VideoCapture, err error) {
+	vc = VideoCapture{p: C.VideoCapture_New()}
+
+	cURI := C.CString(uri)
+	defer C.free(unsafe.Pointer(cURI))
+
+	C.VideoCapture_Open(vc.p, cURI)
+	return vc, nil
+}
+
+// VideoCaptureDevice opens a VideoCapture from a device and prepares to start capturing
+func VideoCaptureDevice(device int) (vc VideoCapture, err error) {
+	vc = VideoCapture{p: C.VideoCapture_New()}
+	C.VideoCapture_OpenDevice(vc.p, C.int(device))
+	return vc, nil
 }
 
 // Close VideoCapture object.
@@ -27,18 +40,6 @@ func (v *VideoCapture) Close() error {
 	return nil
 }
 
-// Open a video data and prepares to start capturing.
-func (v *VideoCapture) Open(uri string) bool {
-	cURI := C.CString(uri)
-	defer C.free(unsafe.Pointer(cURI))
-	return C.VideoCapture_Open(v.p, cURI) != 0
-}
-
-// OpenDevice opens a video device and prepares to start capturing.
-func (v *VideoCapture) OpenDevice(device int) bool {
-	return C.VideoCapture_OpenDevice(v.p, C.int(device)) != 0
-}
-
 // Release video capture object.
 func (v *VideoCapture) Release() {
 	C.VideoCapture_Release(v.p)
@@ -72,31 +73,32 @@ type VideoWriter struct {
 	p  C.VideoWriter
 }
 
-// NewVideoWriter returns a new video writer.
-func NewVideoWriter() VideoWriter {
-	return VideoWriter{p: C.VideoWriter_New()}
-}
+// VideoWriterFile opens a VideoWriter with a specific output file.
+func VideoWriterFile(name string, fps float64, width int, height int) (vw VideoWriter, err error) {
+	vw = VideoWriter{p: C.VideoWriter_New()}
 
-// Close VideoWriter object.
-func (vw *VideoWriter) Close() error {
-	C.VideoWriter_Close(vw.p)
-	vw.p = nil
-	return nil
-}
-
-// Open a VideoWriter with a specific output file.
-func (vw *VideoWriter) Open(name string, fps float64, width int, height int) {
 	cName := C.CString(name)
 	defer C.free(unsafe.Pointer(cName))
 	C.VideoWriter_Open(vw.p, cName, C.double(fps), C.int(width), C.int(height))
+	return vw, nil
 }
 
-// OpenWithMat opens a VideoWriter with a specific output file
+// VideoWriterFileMat opens a VideoWriter with a specific output file,
 // using the dimensions from a specific Mat.
-func (vw *VideoWriter) OpenWithMat(name string, fps float64, img Mat) {
+func VideoWriterFileMat(name string, fps float64, img Mat) (vw VideoWriter, err error) {
+	vw = VideoWriter{p: C.VideoWriter_New()}
+
 	cName := C.CString(name)
 	defer C.free(unsafe.Pointer(cName))
 	C.VideoWriter_OpenWithMat(vw.p, cName, C.double(fps), img.p)
+	return vw, nil
+}
+
+// Close VideoWriter object.
+func (vw *VideoWriter) Close() error {
+	C.VideoWriter_Close(vw.p)
+	vw.p = nil
+	return nil
 }
 
 // IsOpened checks if the VideoWriter is open and ready to be written to.
@@ -106,8 +108,9 @@ func (vw *VideoWriter) IsOpened() bool {
 }
 
 // Write a single Mat image to the open VideoWriter.
-func (vw *VideoWriter) Write(img Mat) {
+func (vw *VideoWriter) Write(img Mat) error {
 	vw.mu.Lock()
 	defer vw.mu.Unlock()
 	C.VideoWriter_Write(vw.p, img.p)
+	return nil
 }