feat(camview): Add native live camera viewer

2026-07-24 22:05:07 +00:00 · 2026-07-04 09:40:46 +02:00
parent 57c82eb3a0
commit 799ff27b74
5 changed files with 472 additions and 0 deletions
--- a/README.md
+++ b/README.md
@@ -80,3 +80,9 @@ Usage: cam2ip [<flags>]
  * `/html`: HTML handler, frames are pushed to canvas over websocket
  * `/jpeg`: Static JPEG handler
  * `/mjpeg`: Motion JPEG, supported natively in major web browsers
+
+### camview
+
+`cmd/camview` is a small native window that shows the local camera live, using [iv](https://github.com/gen2brain/iv) for display.
+
+    go install github.com/gen2brain/cam2ip/cmd/camview@latest
--- a/cmd/camview/go.mod
+++ b/cmd/camview/go.mod
@@ -0,0 +1,27 @@
+module github.com/gen2brain/cam2ip/cmd/camview
+
+go 1.26
+
+require (
+	github.com/gen2brain/cam2ip v1.7.1-0.20260704073444-57c82eb3a02e
+	github.com/gen2brain/iv v0.3.0
+)
+
+require (
+	codeberg.org/tesselslate/wl v0.3.24 // indirect
+	codeberg.org/tesselslate/wl-protocols v0.3.47 // indirect
+	github.com/NeowayLabs/drm v0.0.0-20190824133025-4939fc0ad345 // indirect
+	github.com/dblohm7/wingoes v0.0.0-20260526185140-fb298caac7ca // indirect
+	github.com/ebitengine/purego v0.10.1 // indirect
+	github.com/gen2brain/base64 v0.2.0 // indirect
+	github.com/gen2brain/jpegn v0.4.2 // indirect
+	github.com/gen2brain/shm v0.2.2 // indirect
+	github.com/holoplot/go-evdev v0.0.0-20260504100651-66d1748fe847 // indirect
+	github.com/jezek/xgb v1.3.1 // indirect
+	github.com/korandiz/v4l v1.1.0 // indirect
+	github.com/pbnjay/pixfont v0.0.0-20200714042608-33b744692567 // indirect
+	github.com/pixiv/go-libjpeg v0.0.0-20190822045933-3da21a74767d // indirect
+	github.com/tailscale/win v0.0.0-20260619195133-2d76c33a64c1 // indirect
+	golang.org/x/exp v0.0.0-20260611194520-c48552f49976 // indirect
+	golang.org/x/sys v0.46.0 // indirect
+)
--- a/cmd/camview/go.sum
+++ b/cmd/camview/go.sum
@@ -0,0 +1,42 @@
+codeberg.org/tesselslate/wl v0.3.24 h1:49Gb1vt2Qp5Wl3KudHmPe2Cq1zg2WR8YPtTnHhdodBE=
+codeberg.org/tesselslate/wl v0.3.24/go.mod h1:9eLDoCveYvMpKcUIqig1ctVKrQm5f8aoCHlgDWvyf/U=
+codeberg.org/tesselslate/wl-protocols v0.3.47 h1:TTIPtEsCoWDh2qD5Z4n9VCBc0unNDGVClmk9+VLoBAw=
+codeberg.org/tesselslate/wl-protocols v0.3.47/go.mod h1:Dtk2EZR1jSFZIWZOSVuaZeoQJpo9qJon1D59lt7DYPE=
+github.com/NeowayLabs/drm v0.0.0-20190824133025-4939fc0ad345 h1:gsz1u5J8hnoPtBaA5dUdluC4lZNYgYRZmEchdxTuNxc=
+github.com/NeowayLabs/drm v0.0.0-20190824133025-4939fc0ad345/go.mod h1:B8Pf8lJWIsLTs7oyWkXOWOGAZiQQVomlZurKAgx8HBA=
+github.com/dblohm7/wingoes v0.0.0-20260526185140-fb298caac7ca h1:h1Awca4lQOspNR/2eeo04Ricn5NixDX9mb17WSAgLhQ=
+github.com/dblohm7/wingoes v0.0.0-20260526185140-fb298caac7ca/go.mod h1:2TGl1jRJrRpbzykmg7asHm3h08TqutUgQqY5v9k/g3c=
+github.com/ebitengine/purego v0.10.1 h1:dewVBCBT2GaMu1SrNTYxQhgQBethzfhiwvZiLGP/qyY=
+github.com/ebitengine/purego v0.10.1/go.mod h1:iIjxzd6CiRiOG0UyXP+V1+jWqUXVjPKLAI0mRfJZTmQ=
+github.com/gen2brain/base64 v0.2.0 h1:tIkh2/g6oiDKGfLfsbFEXmSeb5lxyTGbaFV2rQwpcaw=
+github.com/gen2brain/base64 v0.2.0/go.mod h1:tiBvPzg3qFDIggMPy0TEedCJVCeNOhDYeJMErNqvZNk=
+github.com/gen2brain/cam2ip v1.7.1-0.20260704073444-57c82eb3a02e h1:MSd4ptIXGkD6JfFRC4WZ0ULo4CIxMnuH6uv1TZP+RnM=
+github.com/gen2brain/cam2ip v1.7.1-0.20260704073444-57c82eb3a02e/go.mod h1:cjpZVlBsNVzYEGkgtrEoJQFT3mi9ND1ZQ9h3VfGp56Y=
+github.com/gen2brain/iv v0.3.0 h1:c8N+mWOqdf354PbEKS/EFm8SRkUw3y1Wacin1x5t+OE=
+github.com/gen2brain/iv v0.3.0/go.mod h1:LVyZXPg3Jpu/sAAeLHZjOOuo9lzOjo2+gDPz0pueFDk=
+github.com/gen2brain/jpegn v0.4.2 h1:sxy2yolV1eNA02uYtnqBFm4EIC3ETnars98aG7Dc4LM=
+github.com/gen2brain/jpegn v0.4.2/go.mod h1:YvcVOmVPSAsefH6yn9HBW3uY0EHlZwCMoiJXoAWfgL0=
+github.com/gen2brain/shm v0.2.2 h1:CmyCEXB392Mva9kdpec09CAhVZJIx9YhA/CFoWke0iE=
+github.com/gen2brain/shm v0.2.2/go.mod h1:UgIcVtvmOu+aCJpqJX7GOtiN7X2ct+TKLg4RTxwPIUA=
+github.com/holoplot/go-evdev v0.0.0-20260504100651-66d1748fe847 h1:1rQ5UQXFm02DXEtsIpotfA32WJ9KceS6t8w5K8QtFqc=
+github.com/holoplot/go-evdev v0.0.0-20260504100651-66d1748fe847/go.mod h1:iHAf8OIncO2gcQ8XOjS7CMJ2aPbX2Bs0wl5pZyanEqk=
+github.com/jezek/xgb v1.3.1 h1:NQCAEfQyzN+3RjWUSHBuVIxQcy2YfG3/mNvKfs/0rEg=
+github.com/jezek/xgb v1.3.1/go.mod h1:nrhwO0FX/enq75I7Y7G8iN1ubpSGZEiA3v9e9GyRFlk=
+github.com/korandiz/v4l v1.1.0 h1:VbzaWlhqNzVPfHEYEM+V8T7184ndiEzljJgDHSHc7pc=
+github.com/korandiz/v4l v1.1.0/go.mod h1:pftxPG7hkuUgepioAY6PAE81mShaVjzd95X/WF4Izus=
+github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646 h1:zYyBkD/k9seD2A7fsi6Oo2LfFZAehjjQMERAvZLEDnQ=
+github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646/go.mod h1:jpp1/29i3P1S/RLdc7JQKbRpFeM1dOBd8T9ki5s+AY8=
+github.com/pbnjay/pixfont v0.0.0-20200714042608-33b744692567 h1:pKjmNHL7BCXhgsnSlN6Ov3WAN2jbJMCx6IvrMN9GNfc=
+github.com/pbnjay/pixfont v0.0.0-20200714042608-33b744692567/go.mod h1:ytYavTmrpWG4s7UOfDhP6m4ASL5XA66nrOcUn1e2M78=
+github.com/pixiv/go-libjpeg v0.0.0-20190822045933-3da21a74767d h1:ls+7AYarUlUSetfnN/DKVNcK6W8mQWc6VblmOm4XwX0=
+github.com/pixiv/go-libjpeg v0.0.0-20190822045933-3da21a74767d/go.mod h1:DO7ixpslN6XfbWzeNH9vkS5CF2FQUX81B85rYe9zDxU=
+github.com/tailscale/win v0.0.0-20260619195133-2d76c33a64c1 h1:QzOW7bZOlg5/hi1W6dStSN9qazTHkHj5kO7sTA5aymY=
+github.com/tailscale/win v0.0.0-20260619195133-2d76c33a64c1/go.mod h1:vwG7VvIPzIYNJd0Nio6PZW7yr8KNNFEc8EVQ+J/B4bk=
+github.com/tc-hib/winres v0.2.1 h1:YDE0FiP0VmtRaDn7+aaChp1KiF4owBiJa5l964l5ujA=
+github.com/tc-hib/winres v0.2.1/go.mod h1:C/JaNhH3KBvhNKVbvdlDWkbMDO9H4fKKDaN7/07SSuk=
+golang.org/x/exp v0.0.0-20260611194520-c48552f49976 h1:X8Hz2ImujgbmetVuW+w2YkyZChE3cBpZi2P158rTG9M=
+golang.org/x/exp v0.0.0-20260611194520-c48552f49976/go.mod h1:vnf4pv9iKZXY58sQE1L86zmNWJ4159e1RkcWiLCkeEY=
+golang.org/x/image v0.12.0 h1:w13vZbU4o5rKOFFR8y7M+c4A5jXDC0uXTdHYRP8X2DQ=
+golang.org/x/image v0.12.0/go.mod h1:Lu90jvHG7GfemOIcldsh9A2hS01ocl6oNO7ype5mEnk=
+golang.org/x/sys v0.46.0 h1:noSf2Fq6F8DBgS+LysIkx7rIExoNHJsxOAtPp4rthXw=
+golang.org/x/sys v0.46.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
--- a/cmd/camview/icon.png
+++ b/cmd/camview/icon.png
--- a/cmd/camview/main.go
+++ b/cmd/camview/main.go
@@ -0,0 +1,397 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	_ "embed"
+	"flag"
+	"fmt"
+	"image"
+	"image/png"
+	"os"
+	"runtime"
+	"runtime/debug"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/gen2brain/iv"
+
+	"github.com/gen2brain/cam2ip/camera"
+)
+
+const name = "camview"
+
+//go:embed icon.png
+var iconPNG []byte
+
+var version string
+
+func init() {
+	if version != "" {
+		return
+	}
+
+	buildInfo, ok := debug.ReadBuildInfo()
+	if !ok {
+		return
+	}
+
+	if buildInfo.Main.Version != "" {
+		version = buildInfo.Main.Version
+	}
+
+	for _, kv := range buildInfo.Settings {
+		if kv.Key == "vcs.revision" && kv.Value != "" {
+			version = kv.Value
+			if len(version) > 7 {
+				version = version[:7]
+			}
+		}
+	}
+}
+
+func main() {
+	runtime.LockOSThread()
+
+	var (
+		index       int
+		device      string
+		listDevices bool
+		width       float64
+		height      float64
+		rotate      int
+		flip        string
+		timestamp   bool
+		timeFormat  string
+		fps         int
+		fullscreen  bool
+		showVersion bool
+	)
+
+	flag.IntVar(&index, "index", 0, "Camera index")
+	flag.StringVar(&device, "device", "", "Camera name to use, matched as substring, overrides index")
+	flag.BoolVar(&listDevices, "list-devices", false, "List available cameras and exit")
+	flag.Float64Var(&width, "width", 640, "Frame width")
+	flag.Float64Var(&height, "height", 480, "Frame height")
+	flag.IntVar(&rotate, "rotate", 0, "Rotate image, valid values are 90, 180, 270")
+	flag.StringVar(&flip, "flip", "", "Flip image, valid values are horizontal and vertical")
+	flag.BoolVar(&timestamp, "timestamp", false, "Draws timestamp on image")
+	flag.StringVar(&timeFormat, "time-format", "2006-01-02 15:04:05", "Time format")
+	flag.IntVar(&fps, "fps", 30, "Maximum frames per second to display")
+	flag.BoolVar(&fullscreen, "fullscreen", false, "Start in fullscreen")
+	flag.BoolVar(&showVersion, "version", false, "Print version and exit")
+	flag.Parse()
+
+	if showVersion {
+		fmt.Printf("%s %s\n", name, version)
+		os.Exit(0)
+	}
+
+	if listDevices {
+		devices, err := camera.Devices()
+		if err != nil {
+			stderr("%s\n", err.Error())
+			os.Exit(1)
+		}
+
+		for _, d := range devices {
+			if d.Path != "" {
+				fmt.Printf("%d: %s (%s)\n", d.Index, d.Name, d.Path)
+			} else {
+				fmt.Printf("%d: %s\n", d.Index, d.Name)
+			}
+		}
+
+		os.Exit(0)
+	}
+
+	if fps < 1 {
+		fps = 1
+	}
+
+	if device != "" {
+		idx, err := deviceIndex(device)
+		if err != nil {
+			stderr("%s\n", err.Error())
+			os.Exit(1)
+		}
+
+		index = idx
+	}
+
+	cam, err := camera.New(camera.Options{
+		Index:      index,
+		Rotate:     rotate,
+		Flip:       flip,
+		Width:      width,
+		Height:     height,
+		Timestamp:  timestamp,
+		TimeFormat: timeFormat,
+	})
+	if err != nil {
+		stderr("%s\n", err.Error())
+		os.Exit(1)
+	}
+
+	banner(index, cam.Info())
+
+	view, err := iv.New(iv.Options{AppID: name, Width: int(width), Height: int(height)})
+	if err != nil {
+		cam.Close()
+		stderr("%s\n", err.Error())
+		os.Exit(1)
+	}
+
+	_ = view.SetTitle(title(index))
+
+	if icon := appIcon(); icon != nil {
+		_ = view.SetIcon(icon)
+	}
+
+	if fullscreen {
+		_ = view.ToggleFullscreen()
+	}
+
+	s := &stream{}
+	done := make(chan struct{})
+
+	var closeOnce sync.Once
+	quit := func() {
+		closeOnce.Do(func() { close(done) })
+		s.wake()
+	}
+
+	view.SetClosedHandler(quit)
+	view.SetKeyPressHandler(func(key int) {
+		switch key {
+		case iv.KeyEscape, iv.KeyQ:
+			quit()
+		case iv.KeyF, iv.KeyF11:
+			_ = view.ToggleFullscreen()
+		}
+	})
+
+	captureDone := make(chan struct{})
+	go func() {
+		defer close(captureDone)
+		defer cam.Close()
+
+		capture(cam, s, fps, isTerminal(os.Stderr), done)
+	}()
+
+	blank := image.NewRGBA(image.Rect(0, 0, 1, 1))
+
+	for {
+		select {
+		case <-done:
+		default:
+			img, ctx := s.frame()
+			if img == nil {
+				img = blank
+			}
+
+			if err := view.Display(ctx, img, "", true); err != nil {
+				stderr("%s\n", err.Error())
+				quit()
+			}
+
+			continue
+		}
+
+		break
+	}
+
+	// Capture owns and closes the camera; bound the wait so a stall cannot hang exit.
+	select {
+	case <-captureDone:
+	case <-time.After(time.Second):
+	}
+
+	view.Close()
+}
+
+// stream holds the latest frame and wakes the display loop when a new one arrives.
+type stream struct {
+	mu     sync.Mutex
+	img    image.Image
+	cancel context.CancelFunc
+}
+
+// set stores a new frame and wakes the in-flight Display.
+func (s *stream) set(img image.Image) {
+	s.mu.Lock()
+	s.img = img
+	s.mu.Unlock()
+
+	s.wake()
+}
+
+// wake cancels the in-flight Display so the display loop advances.
+func (s *stream) wake() {
+	s.mu.Lock()
+	cancel := s.cancel
+	s.mu.Unlock()
+
+	if cancel != nil {
+		cancel()
+	}
+}
+
+// frame returns the latest image and a context that stays live until the next
+// frame arrives or the viewer is asked to quit.
+func (s *stream) frame() (image.Image, context.Context) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	s.cancel = cancel
+
+	return s.img, ctx
+}
+
+// capture reads the newest frame until quit; Read() paces the loop, fps caps it.
+// When showFPS is set it reports the measured rate on a single overwritten line.
+func capture(cam *camera.Camera, s *stream, fps int, showFPS bool, done <-chan struct{}) {
+	interval := time.Second / time.Duration(fps)
+	next := time.Now()
+
+	frames := 0
+	mark := time.Now()
+	reported := false
+
+	if showFPS {
+		defer func() {
+			if reported {
+				fmt.Fprintln(os.Stderr)
+			}
+		}()
+	}
+
+	for {
+		select {
+		case <-done:
+			return
+		default:
+		}
+
+		img, err := cam.Read()
+		if err != nil {
+			select {
+			case <-done:
+				return
+			default:
+			}
+
+			stderr("%s\n", err.Error())
+
+			select {
+			case <-done:
+				return
+			case <-time.After(100 * time.Millisecond):
+			}
+
+			next = time.Now()
+
+			continue
+		}
+
+		s.set(img)
+
+		if frames++; showFPS {
+			if d := time.Since(mark); d >= time.Second {
+				fmt.Fprintf(os.Stderr, "\rFPS: %5.1f", float64(frames)/d.Seconds())
+				reported = true
+				frames = 0
+				mark = time.Now()
+			}
+		}
+
+		if next = next.Add(interval); time.Until(next) <= 0 {
+			next = time.Now()
+
+			continue
+		}
+
+		select {
+		case <-done:
+			return
+		case <-time.After(time.Until(next)):
+		}
+	}
+}
+
+func appIcon() image.Image {
+	img, err := png.Decode(bytes.NewReader(iconPNG))
+	if err != nil {
+		return nil
+	}
+
+	return img
+}
+
+// banner prints the device and negotiated format on startup.
+func banner(index int, info camera.Info) {
+	fmt.Fprintf(os.Stderr, "%s %s\n", name, version)
+
+	if n := deviceName(index); n != "" {
+		fmt.Fprintf(os.Stderr, "  device  %s\n", n)
+	}
+
+	fmt.Fprintf(os.Stderr, "  format  %s %dx%d\n", info.Format, info.Width, info.Height)
+}
+
+func title(index int) string {
+	if n := deviceName(index); n != "" {
+		return fmt.Sprintf("%s - %s", name, n)
+	}
+
+	return name
+}
+
+func stderr(format string, a ...any) {
+	_, _ = fmt.Fprintf(os.Stderr, format, a...)
+}
+
+// isTerminal reports whether f is a character device (a terminal).
+func isTerminal(f *os.File) bool {
+	stat, err := f.Stat()
+	if err != nil {
+		return false
+	}
+
+	return stat.Mode()&os.ModeCharDevice != 0
+}
+
+// deviceName returns the name of the camera at index, or an empty string.
+func deviceName(index int) string {
+	devices, err := camera.Devices()
+	if err != nil {
+		return ""
+	}
+
+	for _, d := range devices {
+		if d.Index == index {
+			return d.Name
+		}
+	}
+
+	return ""
+}
+
+// deviceIndex returns the index of the first camera whose name contains the query.
+func deviceIndex(name string) (int, error) {
+	devices, err := camera.Devices()
+	if err != nil {
+		return 0, err
+	}
+
+	want := strings.ToLower(name)
+	for _, d := range devices {
+		if strings.Contains(strings.ToLower(d.Name), want) {
+			return d.Index, nil
+		}
+	}
+
+	return 0, fmt.Errorf("camera: no device matching %q", name)
+}