Add rotate option

camera/camera_cv3.go

@@ -7,25 +7,34 @@ import (
 	"fmt"
 	"image"
 
+	"github.com/disintegration/imaging"
 	"gocv.io/x/gocv"
 )
 
+// Options.
+type Options struct {
+	Index  int
+	Rotate int
+}
+
 // Camera represents camera.
 type Camera struct {
+	opts   Options
 	camera *gocv.VideoCapture
 	frame  *gocv.Mat
 }
 
 // New returns new Camera for given camera index.
-func New(index int) (camera *Camera, err error) {
+func New(opts Options) (camera *Camera, err error) {
 	camera = &Camera{}
+	camera.opts = opts
 
 	mat := gocv.NewMat()
 	camera.frame = &mat
 
-	camera.camera, err = gocv.VideoCaptureDevice(index)
+	camera.camera, err = gocv.VideoCaptureDevice(opts.Index)
 	if err != nil {
-		err = fmt.Errorf("camera: can not open camera %d: %s", index, err.Error())
+		err = fmt.Errorf("camera: can not open camera %d: %s", opts.Index, err.Error())
 	}
 
 	return
@@ -45,6 +54,24 @@ func (c *Camera) Read() (img image.Image, err error) {
 		return
 	}
 
+	if c.frame == nil {
+		err = fmt.Errorf("camera: can not grab frame")
+		return
+	}
+
+	if c.opts.Rotate == 0 {
+		return
+	}
+
+	switch c.opts.Rotate {
+	case 90:
+		img = imaging.Rotate90(img)
+	case 180:
+		img = imaging.Rotate180(img)
+	case 270:
+		img = imaging.Rotate270(img)
+	}
+
 	return
 }