Not really closer but less crashy

examples/multisyswebcam/main.go

@@ -0,0 +1,52 @@
+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/multisyswebcam"
+	"git.martyn.berlin/martyn/fyne-widgets/pkg/layouts"
+)
+
+var multisysWebcamID int
+var multisysWebcamLabel *widget.Label
+var multisysWebcamWidget *multisyswebcam.MultisysWebcam
+
+func switchMultisysWebcam(id int) {
+	multisysWebcamLabel.Text = "Webcam: " + strconv.Itoa(id)
+	multisysWebcamLabel.Refresh()
+	multisysWebcamWidget.MultisysWebcamID = int64(id)
+	multisysWebcamWidget.Refresh()
+}
+
+func incWebCamID() {
+	multisysWebcamID = multisysWebcamID + 1
+	switchMultisysWebcam(multisysWebcamID)
+}
+
+func decWebCamID() {
+	multisysWebcamID = multisysWebcamID - 1
+	switchMultisysWebcam(multisysWebcamID)
+}
+
+func main() {
+	a := app.New()
+	w := a.NewWindow("MultisysWebcam")
+
+	multisysWebcamWidget = multisyswebcam.NewMultisysWebcam()
+	layout := layouts.NewFloatingControlsLayout()
+	layout.FloatingControlsLocation = layouts.FloatingControlsCenter
+	multisysWebcamWidget.System = multisyswebcam.WebcamSystemGoCV
+	multisysWebcamID = 0
+	multisysWebcamWidget.UpdateFPS = 50
+
+	multisysWebcamLabel = widget.NewLabel("Webcam: 0")
+	buttons := container.NewHBox(multisysWebcamLabel, widget.NewButton("-", decWebCamID), widget.NewButton("+", incWebCamID))
+
+	w.SetContent(container.New(&layout, multisysWebcamWidget, buttons))
+	w.Resize(fyne.NewSize(640, 480))
+	w.ShowAndRun()
+}

pkg/multisyswebcam/multisyswebcam.go

@@ -0,0 +1,136 @@
+package multisyswebcam
+
+import (
+	"image"
+	"image/color"
+	"time"
+	"math/rand"
+
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/canvas"
+	"fyne.io/fyne/v2/widget"
+	"gocv.io/x/gocv"
+)
+
+var _ fyne.WidgetRenderer = (*multisysMultisysWebcamRenderer)(nil)
+
+type WebcamSystem int64
+
+const (
+	WebcamSystemDisabled WebcamSystem = iota
+	WebcamSystemGoCV
+	WebcamSystemWinAviCapDll
+)
+
+
+type MultisysWebcam struct {
+	widget.BaseWidget
+
+	System WebcamSystem
+
+	MultisysWebcamID int64
+	UpdateFPS    int64
+	fpsTimer     *time.Ticker
+
+}
+
+func NewMultisysWebcam() *MultisysWebcam {
+	w := &MultisysWebcam{}
+	w.ExtendBaseWidget(w)
+	w.MultisysWebcamID = 0
+	w.UpdateFPS = 25
+	w.System = WebcamSystemDisabled
+
+	return w
+}
+
+func (w *MultisysWebcam) Resize(s fyne.Size) {
+	w.BaseWidget.Resize(s)
+}
+
+func (w *MultisysWebcam) CreateRenderer() fyne.WidgetRenderer {
+	fpsTimer := time.NewTicker(time.Duration(1000/25) * time.Millisecond)
+	go func(w *MultisysWebcam) {
+		for {
+			_ = <-fpsTimer.C
+			if w != nil {
+				w.Refresh()
+			}
+		}
+	}(w)
+	return newMultisysWebcamRenderer(w)
+}
+
+func staticNoiseImage(w, h int) *image.RGBA {
+	i := image.NewRGBA(image.Rect(0, 0, w, h))
+	for x := 0; x < w; x++ {
+		for y := 0; y < h; y++ {
+			lum := uint8(rand.Float32() * 255)
+			i.Set(x, y, color.RGBA{lum, lum, lum, 255})
+		}
+	}
+	return i
+}
+
+func (w *MultisysWebcam) actualrenderframe(width, height int) image.Image {
+	switch w.System {
+	case WebcamSystemDisabled:
+		return staticNoiseImage(width,height)
+	case WebcamSystemGoCV:
+		gocvWebcam, _ := gocv.VideoCaptureDevice(int(w.MultisysWebcamID))
+		img := gocv.NewMat()
+		gocvWebcam.Read(&img)
+		frameImage, err := img.ToImage()
+		if err != nil {
+			frameImage = image.NewRGBA(image.Rect(0, 0, width, height))
+		}
+		return frameImage
+	}
+	return image.NewRGBA(image.Rect(0, 0, width, height))
+}
+
+func newMultisysWebcamRenderer(w *MultisysWebcam) *multisysMultisysWebcamRenderer {
+	renderer := &multisysMultisysWebcamRenderer{
+		multisysMultisysWebcam: w,
+		background:     canvas.NewRectangle(color.RGBA{255, 0, 255, 255}),
+	}
+	renderer.currentframe = canvas.NewRaster(w.actualrenderframe)
+	return renderer
+}
+
+type multisysMultisysWebcamRenderer struct {
+	multisysMultisysWebcam   *MultisysWebcam
+	background       *canvas.Rectangle
+	currentframe     *canvas.Raster
+	goCVVideoCapture *gocv.VideoCapture
+}
+
+func (r *multisysMultisysWebcamRenderer) Objects() []fyne.CanvasObject {
+	// The order is critical, rect is drawn first then currentframe
+	return []fyne.CanvasObject{r.background, r.currentframe}
+}
+
+func (r *multisysMultisysWebcamRenderer) Layout(s fyne.Size) {
+	r.background.Resize(s)
+	r.currentframe.Resize(s)
+}
+
+func (r *multisysMultisysWebcamRenderer) MinSize() fyne.Size {
+	return fyne.NewSize(200, 200)
+}
+
+func (r *multisysMultisysWebcamRenderer) Refresh() {
+	if r != nil {
+		if r.currentframe != nil {
+			r.currentframe.Refresh()
+		}
+	}
+}
+
+func (r *multisysMultisysWebcamRenderer) Destroy() {
+	if r.multisysMultisysWebcam != nil {
+		if r.multisysMultisysWebcam.fpsTimer != nil {
+			r.multisysMultisysWebcam.fpsTimer.Stop()
+		}
+	}
+} // Called when the renderer is destroyed