uidriver/js: Bug fix: Needed to initialize pseudoScale with the given scale

Updates #960, #973

examples/moire/main.go

@@ -70,8 +70,6 @@ func update(screen *ebiten.Image) error {
 			screenScale = 2
 		case 2:
 			screenScale = 1
-		case 0:
-			// screenScale can be 0 on browsers or mobiles. Ignore this.
 		default:
 			panic("not reached")
 		}
@@ -79,9 +77,7 @@ func update(screen *ebiten.Image) error {
 	if inpututil.IsKeyJustPressed(ebiten.KeyF) {
 		fullscreen = !fullscreen
 	}
-	if screenScale > 0 {
 	ebiten.SetScreenScale(screenScale)
-	}
 	ebiten.SetFullscreen(fullscreen)
 
 	if ebiten.IsDrawingSkipped() {

examples/windowsize/main.go

@@ -108,8 +108,6 @@ func update(screen *ebiten.Image) error {
 			screenScale = 2
 		case 2:
 			screenScale = 0.75
-		case 0:
-			// screenScale can be 0 on browsers or mobiles. Ignore this.
 		default:
 			panic("not reached")
 		}
@@ -142,9 +140,7 @@ func update(screen *ebiten.Image) error {
 	}
 
 	ebiten.SetScreenSize(screenWidth, screenHeight)
-	if screenScale > 0 {
 	ebiten.SetScreenScale(screenScale)
-	}
 	ebiten.SetFullscreen(fullscreen)
 	ebiten.SetRunnableInBackground(runnableInBackground)
 	ebiten.SetCursorVisible(cursorVisible)

internal/uidriver/js/ui.go

@@ -424,6 +424,7 @@ func (u *UserInterface) Run(width, height int, scale float64, title string, cont
 
 	document.Set("title", title)
 	u.setScreenSize(width, height)
+	u.pseudoScale = scale
 	canvas.Call("focus")
 	ch := u.loop(context)
 	if runtime.GOARCH == "wasm" {

run.go

@@ -240,7 +240,7 @@ func SetScreenScale(scale float64) {
 
 // ScreenScale returns the current screen scale.
 //
-// ScreenScale returns a value set by SetScreenScale or Run on browsers.
+// On browsers, this value does not affect actual rendering.
 //
 // If Run is not called, this returns 0.
 //