feat: add option WindowInitialLocations

Author: pchampio

application.go

@@ -100,13 +100,25 @@ func (a *Application) Run() error {
 		return errors.Errorf("invalid window mode %T", a.config.windowMode)
 	}
 
+	if a.config.windowInitialLocations.xpos != 0 {
+		// To create the window at a specific position, make it initially invisible
+		// using the Visible window hint, set its position and then show it.
+		glfw.WindowHint(glfw.Visible, glfw.False)
+	}
+
 	a.window, err = glfw.CreateWindow(a.config.windowInitialDimensions.width, a.config.windowInitialDimensions.height, "Loading..", monitor, nil)
 	if err != nil {
 		return errors.Wrap(err, "creating glfw window")
 	}
 	glfw.DefaultWindowHints()
 	defer a.window.Destroy()
 
+	if a.config.windowInitialLocations.xpos != 0 {
+		a.window.SetPos(a.config.windowInitialLocations.xpos,
+			a.config.windowInitialLocations.ypos)
+		a.window.Show()
+	}
+
 	a.resourceWindow, err = createResourceWindow(a.window)
 	if err != nil {
 		fmt.Printf("go-flutter: WARNING %v\n", err)

option.go

@@ -16,6 +16,7 @@ type config struct {
 	windowInitializerDeprecated func(*glfw.Window) error
 	windowIconProvider          func() ([]image.Image, error)
 	windowInitialDimensions     windowDimensions
+	windowInitialLocations      windowLocations
 	windowDimensionLimits       windowDimensionLimits
 	windowMode                  windowMode
 
@@ -30,6 +31,11 @@ type windowDimensions struct {
 	height int
 }
 
+type windowLocations struct {
+	xpos int
+	ypos int
+}
+
 type windowDimensionLimits struct {
 	minWidth  int
 	minHeight int
@@ -118,6 +124,25 @@ func WindowInitialDimensions(width, height int) Option {
 	}
 }
 
+// WindowInitialLocations specify the startup's position of the window.
+// Location, in screen coordinates, of the upper-left corner of the client area
+// of the window.
+func WindowInitialLocations(xpos, ypos int) Option {
+	if xpos < 1 {
+		fmt.Println("go-flutter: invalid initial value for xpos location, must be 1 or greater.")
+		os.Exit(1)
+	}
+	if ypos < 1 {
+		fmt.Println("go-flutter: invalid initial value for ypos location, must be 1 or greater.")
+		os.Exit(1)
+	}
+
+	return func(c *config) {
+		c.windowInitialLocations.xpos = xpos
+		c.windowInitialLocations.ypos = ypos
+	}
+}
+
 // WindowDimensionLimits specify the dimension limits of the window.
 // Does not work when the window is fullscreen or not resizable.
 func WindowDimensionLimits(minWidth, minHeight, maxWidth, maxHeight int) Option {