Add support for native V4L implementation on Linux/RPi

camera/camera_cv3.go

@@ -1,4 +1,4 @@
-// +build cv3
+// +build cv3,!native
 
 // Package camera.
 package camera
@@ -15,6 +15,8 @@ import (
 type Options struct {
 	Index  int
 	Rotate int
+	Width  float64
+	Height float64
 }
 
 // Camera represents camera.
@@ -37,6 +39,9 @@ func New(opts Options) (camera *Camera, err error) {
 		err = fmt.Errorf("camera: can not open camera %d: %s", opts.Index, err.Error())
 	}
 
+	camera.SetProperty(PropFrameWidth, opts.Width)
+	camera.SetProperty(PropFrameHeight, opts.Height)
+
 	return
 }
 
@@ -55,7 +60,7 @@ func (c *Camera) Read() (img image.Image, err error) {
 	}
 
 	if c.frame == nil {
-		err = fmt.Errorf("camera: can not grab frame")
+		err = fmt.Errorf("camera: can not retrieve frame")
 		return
 	}