ui: Bug fix: DeviceScaleFactor should return the current monitor's scale

internal/devicescale/devicescale.go

@@ -22,10 +22,6 @@ var (
 	m sync.Mutex
 )
 
-func Get() float64 {
-	return GetAt(0, 0)
-}
-
 func GetAt(x, y int) float64 {
 	m.Lock()
 	defer m.Unlock()

internal/ui/ui_glfw.go

@@ -495,6 +495,21 @@ func SetWindowDecorated(decorated bool) {
 	//     return nil
 }
 
+func DeviceScaleFactor() float64 {
+	f := 0.0
+	u := currentUI
+	if !u.isRunning() {
+		return devicescale.GetAt(currentMonitor().GetPos())
+	}
+
+	_ = u.runOnMainThread(func() error {
+		m := u.currentMonitor()
+		f = devicescale.GetAt(m.GetPos())
+		return nil
+	})
+	return f
+}
+
 func Run(width, height int, scale float64, title string, g GraphicsContext, mainloop bool) error {
 	u := currentUI
 	// GLContext must be created before setting the screen size, which requires

internal/ui/ui_mobile.go

@@ -84,7 +84,7 @@ func getDeviceScale() float64 {
 	defer deviceScaleM.Unlock()
 
 	if deviceScaleVal == 0 {
-		deviceScaleVal = devicescale.Get()
+		deviceScaleVal = devicescale.GetAt(0, 0)
 	}
 	return deviceScaleVal
 }

run.go

@@ -23,7 +23,6 @@ import (
 	"sync/atomic"
 
 	"github.com/hajimehoshi/ebiten/internal/clock"
-	"github.com/hajimehoshi/ebiten/internal/devicescale"
 	"github.com/hajimehoshi/ebiten/internal/png"
 	"github.com/hajimehoshi/ebiten/internal/shareable"
 	"github.com/hajimehoshi/ebiten/internal/ui"
@@ -528,7 +527,7 @@ func SetWindowIcon(iconImages []image.Image) {
 //
 // DeviceScaleFactor is concurrent-safe.
 func DeviceScaleFactor() float64 {
-	return devicescale.Get()
+	return ui.DeviceScaleFactor()
 }
 
 // IsVsyncEnabled returns a boolean value indicating whether