ui: Add SetCursorVisibility (#258)

internal/ui/ui_glfw.go

@@ -142,6 +142,20 @@ func ScreenScale() float64 {
 	return s
 }
 
+func SetCursorVisibility(visible bool) {
+	// This can be called before Run: change the state asyncly.
+	go func() {
+		_ = currentUI.runOnMainThread(func() error {
+			c := glfw.CursorNormal
+			if !visible {
+				c = glfw.CursorHidden
+			}
+			currentUI.window.SetInputMode(glfw.CursorMode, c)
+			return nil
+		})
+	}()
+}
+
 func Run(width, height int, scale float64, title string, g GraphicsContext) error {
 	u := currentUI
 	// GLContext must be created before setting the screen size, which requires

internal/ui/ui_js.go

@@ -57,6 +57,14 @@ func ScreenScale() float64 {
 	return currentUI.scale
 }
 
+func SetCursorVisibility(visibility bool) {
+	if visibility {
+		canvas.Get("style").Set("cursor", "auto")
+	} else {
+		canvas.Get("style").Set("cursor", "none")
+	}
+}
+
 func (u *userInterface) actualScreenScale() float64 {
 	return u.scale * u.deviceScale
 }

internal/ui/ui_mobile.go

@@ -112,6 +112,10 @@ func ScreenScale() float64 {
 	return currentUI.scale
 }
 
+func SetCursorVisibility(visibility bool) {
+	// Do nothing
+}
+
 func (u *userInterface) actualScreenScale() float64 {
 	return u.scale * deviceScale()
 }

run.go

@@ -153,3 +153,10 @@ func ScreenScale() float64 {
 	}
 	return ui.ScreenScale()
 }
+
+// SetCursorVisibility changes the state of cursor visiblity.
+//
+// This function is concurrent-safe.
+func SetCursorVisibility(visible bool) {
+	ui.SetCursorVisibility(visible)
+}