Add support for native V4L implementation on Linux/RPi

camera/camera.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.
@@ -34,6 +36,9 @@ func New(opts Options) (camera *Camera, err error) {
 		err = fmt.Errorf("camera: can not open camera %d", opts.Index)
 	}
 
+	camera.SetProperty(PropFrameWidth, opts.Width)
+	camera.SetProperty(PropFrameHeight, opts.Height)
+
 	return
 }
 
@@ -43,7 +48,7 @@ func (c *Camera) Read() (img image.Image, err error) {
 		c.frame = c.camera.RetrieveFrame(1)
 
 		if c.frame == nil {
-			err = fmt.Errorf("camera: can not grab frame")
+			err = fmt.Errorf("camera: can not retrieve frame")
 			return
 		}
 

camera/camera_const.go

@@ -1,3 +1,5 @@
+// +build !native
+
 package camera
 
 // Property identifiers.

camera/camera_const_native.go

@@ -0,0 +1,21 @@
+// +build native
+
+package camera
+
+import (
+	"github.com/korandiz/v4l"
+)
+
+// Property identifiers.
+const (
+	PropBrightness    = v4l.CtrlBrightness
+	PropContrast      = v4l.CtrlContrast
+	PropSaturation    = v4l.CtrlSaturation
+	PropHue           = v4l.CtrlHue
+	PropGain          = v4l.CtrlGain
+	PropExposure      = v4l.CtrlExposure
+	PropWhiteBalanceU = v4l.CtrlWhiteBalance
+	PropSharpness     = v4l.CtrlSharpness
+	PropWhiteBalanceV = v4l.CtrlDoWhiteBalance
+	PropBacklight     = v4l.CtrlBacklightCompensation
+)

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
 	}
 

camera/camera_native_linux.go

@@ -0,0 +1,132 @@
+// +build native
+
+// Package camera.
+package camera
+
+import (
+	"fmt"
+	"image"
+
+	"github.com/disintegration/imaging"
+	"github.com/korandiz/v4l"
+	"github.com/korandiz/v4l/fmt/mjpeg"
+
+	im "github.com/gen2brain/cam2ip/image"
+)
+
+// Options.
+type Options struct {
+	Index  int
+	Rotate int
+	Width  float64
+	Height float64
+}
+
+// Camera represents camera.
+type Camera struct {
+	opts   Options
+	camera *v4l.Device
+}
+
+// New returns new Camera for given camera index.
+func New(opts Options) (camera *Camera, err error) {
+	camera = &Camera{}
+	camera.opts = opts
+
+	devices := v4l.FindDevices()
+	if len(devices) < opts.Index+1 {
+		err = fmt.Errorf("camera: no camera at index %d", opts.Index)
+		return
+	}
+
+	camera.camera, err = v4l.Open(devices[opts.Index].Path)
+	if err != nil {
+		err = fmt.Errorf("camera: %s", err.Error())
+		return
+	}
+
+	if camera.camera == nil {
+		err = fmt.Errorf("camera: can not open camera %d", opts.Index)
+		return
+	}
+
+	config, err := camera.camera.GetConfig()
+	if err != nil {
+		err = fmt.Errorf("camera: %s", err.Error())
+		return
+	}
+
+	config.Format = mjpeg.FourCC
+	config.Width = int(opts.Width)
+	config.Height = int(opts.Height)
+
+	err = camera.camera.SetConfig(config)
+	if err != nil {
+		err = fmt.Errorf("camera: %s", err.Error())
+		return
+	}
+
+	err = camera.camera.TurnOn()
+	if err != nil {
+		err = fmt.Errorf("camera: %s", err.Error())
+		return
+	}
+
+	return
+}
+
+// Read reads next frame from camera and returns image.
+func (c *Camera) Read() (img image.Image, err error) {
+
+	buffer, err := c.camera.Capture()
+	if err != nil {
+		err = fmt.Errorf("camera: can not grab frame: %s", err.Error())
+		return
+	}
+
+	img, err = im.NewDecoder(buffer).Decode()
+	if err != nil {
+		err = fmt.Errorf("camera: %s", err.Error())
+		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
+}
+
+// GetProperty returns the specified camera property.
+func (c *Camera) GetProperty(id int) float64 {
+	ret, _ := c.camera.GetControl(uint32(id))
+	return float64(ret)
+}
+
+// SetProperty sets a camera property.
+func (c *Camera) SetProperty(id int, value float64) {
+	c.camera.SetControl(uint32(id), int32(value))
+}
+
+// Close closes camera.
+func (c *Camera) Close() (err error) {
+	if c.camera == nil {
+		err = fmt.Errorf("camera: camera is not opened")
+		return
+	}
+
+	c.camera.TurnOff()
+
+	c.camera.Close()
+	c.camera = nil
+	return
+}

camera/camera_test.go

@@ -11,7 +11,7 @@ import (
 )
 
 func TestCamera(t *testing.T) {
-	camera, err := New(1)
+	camera, err := New(Options{0, 0, 640, 480})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -25,18 +25,6 @@ func TestCamera(t *testing.T) {
 
 	defer os.RemoveAll(tmpdir)
 
-	var width, height float64 = 640, 480
-	camera.SetProperty(PropFrameWidth, width)
-	camera.SetProperty(PropFrameHeight, height)
-
-	if camera.GetProperty(PropFrameWidth) != width {
-		t.Error("FrameWidth not correct")
-	}
-
-	if camera.GetProperty(PropFrameHeight) != height {
-		t.Error("FrameHeight not correct")
-	}
-
 	var i int
 	var n int = 10