Webcam with working ticker

examples/webcam/main.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"strconv"
+
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/app"
+	"fyne.io/fyne/v2/container"
+	"fyne.io/fyne/v2/widget"
+	"git.martyn.berlin/martyn/fyne-widgets/pkg/layouts"
+	"git.martyn.berlin/martyn/fyne-widgets/pkg/webcam"
+)
+
+var webcamID int
+var webcamLabel *widget.Label
+var webcamWidget *webcam.Webcam
+
+func switchWebcam(id int) {
+	webcamLabel.Text = "Webcam: " + strconv.Itoa(id)
+	webcamLabel.Refresh()
+	webcamWidget.WebcamID = int64(id)
+	webcamWidget.Refresh()
+}
+
+func incWebCamID() {
+	webcamID = webcamID + 1
+	switchWebcam(webcamID)
+}
+
+func decWebCamID() {
+	webcamID = webcamID - 1
+	switchWebcam(webcamID)
+}
+
+func main() {
+	a := app.New()
+	w := a.NewWindow("Webcam")
+
+	webcamWidget = webcam.NewWebcam()
+	layout := layouts.NewFloatingControlsLayout()
+	layout.FloatingControlsLocation = layouts.FloatingControlsCenter
+	webcamID = 0
+
+	webcamLabel = widget.NewLabel("Webcam: 0")
+	buttons := container.NewHBox(webcamLabel, widget.NewButton("-", decWebCamID), widget.NewButton("+", incWebCamID))
+
+	w.SetContent(container.New(&layout, webcamWidget, buttons))
+	w.Resize(fyne.NewSize(640, 480))
+	w.ShowAndRun()
+}

pkg/webcam/webcam.go

@@ -0,0 +1,97 @@
+package webcam
+
+import (
+	"image"
+	"image/color"
+	"time"
+
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/canvas"
+	"fyne.io/fyne/v2/widget"
+	"gocv.io/x/gocv"
+)
+
+var _ fyne.WidgetRenderer = (*webcamRenderer)(nil)
+
+type Webcam struct {
+	widget.BaseWidget
+
+	WebcamID  int64
+	UpdateFPS int64
+	fpsTimer  *time.Ticker
+}
+
+func NewWebcam() *Webcam {
+	w := &Webcam{}
+	w.ExtendBaseWidget(w)
+	w.WebcamID = 0
+	w.UpdateFPS = 25
+
+	return w
+}
+
+func (w *Webcam) Resize(s fyne.Size) {
+	w.BaseWidget.Resize(s)
+}
+
+func (w *Webcam) CreateRenderer() fyne.WidgetRenderer {
+	fpsTimer := time.NewTicker(time.Duration(1000/25) * time.Millisecond)
+	go func(w *Webcam) {
+		for {
+			_ = <-fpsTimer.C
+			w.Refresh()
+		}
+	}(w)
+	return newWebcamRenderer(w)
+}
+
+type webcamRenderer struct {
+	webcam           *Webcam
+	background       *canvas.Rectangle
+	currentframe     *canvas.Raster
+	goCVVideoCapture *gocv.VideoCapture
+}
+
+func renderframe(w, h int) image.Image {
+	frameImage := image.NewRGBA(image.Rect(0, 0, w, h))
+	return frameImage
+}
+
+func (r *webcamRenderer) actualrenderframe(w, h int) image.Image {
+	webcam, _ := gocv.VideoCaptureDevice(int(r.webcam.WebcamID))
+	img := gocv.NewMat()
+	webcam.Read(&img)
+	frameImage, _ := img.ToImage() //no point doing anything other than returning anyway!
+	return frameImage
+}
+
+func newWebcamRenderer(w *Webcam) *webcamRenderer {
+	renderer := &webcamRenderer{
+		webcam:     w,
+		background: canvas.NewRectangle(color.RGBA{255, 0, 255, 255}),
+	}
+	renderer.currentframe = canvas.NewRaster(renderer.actualrenderframe)
+	return renderer
+}
+
+func (r *webcamRenderer) Objects() []fyne.CanvasObject {
+	// The order is critical, rect is drawn first then currentframe
+	return []fyne.CanvasObject{r.background, r.currentframe}
+}
+
+func (r *webcamRenderer) Layout(s fyne.Size) {
+	r.background.Resize(s)
+	r.currentframe.Resize(s)
+}
+
+func (r *webcamRenderer) MinSize() fyne.Size {
+	return fyne.NewSize(200, 200)
+}
+
+func (r *webcamRenderer) Refresh() {
+	r.currentframe.Refresh()
+}
+
+func (r *webcamRenderer) Destroy() {
+	r.webcam.fpsTimer.Stop()
+} // Called when the renderer is destroyed