Add workaround to use just 1 thread on Apple M1

Downsize is resize is not as smooth, but upside does not crash.

Fixes fyne-io#2188

internal/driver/glfw/driver.go

@@ -37,6 +37,8 @@ type gLDriver struct {
 	drawDone   chan interface{}
 
 	animation *animation.Runner
+
+	drawOnMainThread bool // A workaround on Apple M1, just use 1 thread until fixed upstream
 }
 
 func (d *gLDriver) RenderedTextSize(text string, textSize float32, style fyne.TextStyle) (size fyne.Size, baseline float32) {

internal/driver/glfw/loop.go

@@ -71,8 +71,31 @@ func runOnDraw(w *window, f func()) {
 	<-done
 }
 
+func (d *gLDriver) drawSingleFrame() {
+	refreshingCanvases := make([]fyne.Canvas, 0)
+	for _, win := range d.windowList() {
+		w := win.(*window)
+		w.viewLock.RLock()
+		canvas := w.canvas
+		closing := w.closing
+		visible := w.visible
+		w.viewLock.RUnlock()
+
+		if closing || !canvas.IsDirty() || !visible {
+			continue
+		}
+		d.repaintWindow(w)
+		refreshingCanvases = append(refreshingCanvases, canvas)
+	}
+	cache.CleanCanvases(refreshingCanvases)
+}
+
 func (d *gLDriver) initGLFW() {
 	initOnce.Do(func() {
+		if runtime.GOOS == "darwin" && runtime.GOARCH == "arm64" {
+			d.drawOnMainThread = true
+		}
+
 		err := glfw.Init()
 		if err != nil {
 			fyne.LogError("failed to initialise GLFW", err)
@@ -146,6 +169,10 @@ func (d *gLDriver) runGL() {
 				}
 
 				newWindows = append(newWindows, win)
+
+				if d.drawOnMainThread {
+					d.drawSingleFrame()
+				}
 			}
 			if reassign {
 				d.windowLock.Lock()
@@ -187,7 +214,12 @@ func (d *gLDriver) repaintWindow(w *window) {
 func (d *gLDriver) startDrawThread() {
 	settingsChange := make(chan fyne.Settings)
 	fyne.CurrentApp().Settings().AddChangeListener(settingsChange)
-	draw := time.NewTicker(time.Second / 60)
+	var draw *time.Ticker
+	if d.drawOnMainThread {
+		draw = time.NewTicker(time.Hour * 24 * 365 * 100) // don't tick when on M1
+	} else {
+		draw = time.NewTicker(time.Second / 60)
+	}
 
 	go func() {
 		runtime.LockOSThread()
@@ -213,22 +245,7 @@ func (d *gLDriver) startDrawThread() {
 					go c.reloadScale()
 				})
 			case <-draw.C:
-				refreshingCanvases := make([]fyne.Canvas, 0)
-				for _, win := range d.windowList() {
-					w := win.(*window)
-					w.viewLock.RLock()
-					canvas := w.canvas
-					closing := w.closing
-					visible := w.visible
-					w.viewLock.RUnlock()
-
-					if closing || !canvas.IsDirty() || !visible {
-						continue
-					}
-					d.repaintWindow(w)
-					refreshingCanvases = append(refreshingCanvases, canvas)
-				}
-				cache.CleanCanvases(refreshingCanvases)
+				d.drawSingleFrame()
 			}
 		}
 	}()