Frontend.Maui: fix window size for gtk

Initial window size was too thin so we tried to resize
the window once it's created.

Also extracted default window size to a constant in
FrontendHelpers to prevent code duplication.

Co-authored-by: webwarrior <[email protected]>

src/GWallet.Frontend.Maui/App.xaml.fs

@@ -1,5 +1,6 @@
 namespace GWallet.Frontend.Maui
 
+open Microsoft.Maui
 open Microsoft.Maui.Controls
 open Microsoft.Maui.Controls.Xaml
 
@@ -9,3 +10,13 @@ type App() as this =
 
     do this.LoadFromXaml typeof<App> |> ignore<App>
     do this.MainPage <- (WelcomePage GlobalState) :> Page
+
+#if GTK
+    override _.CreateWindow(activationState) = 
+        let window = base.CreateWindow(activationState)
+        window.Created.Add(fun _ -> 
+            let gtkWindow = MauiGtkApplication.Current.MainWindow
+            gtkWindow.Resize FrontendHelpers.DefaultDesktopWindowSize
+        )
+        window
+#endif

src/GWallet.Frontend.XF.Gtk/Program.fs

@@ -7,6 +7,7 @@ open Xamarin.Forms.Platform.GTK
 
 open GWallet.Backend
 open GWallet.Backend.FSharpUtil.UwpHacks
+open GWallet.Frontend.XF
 
 module Main =
 
@@ -34,7 +35,7 @@ module Main =
             )
         else
             window.SetApplicationIcon logoFileName
-        window.SetDefaultSize (500, 1000)
+        window.SetDefaultSize FrontendHelpers.DefaultDesktopWindowSize
         window.Show()
         Gtk.Application.Run()
         0

src/GWallet.Frontend.XF/FrontendHelpers.fs

@@ -464,3 +464,4 @@ module FrontendHelpers =
         let currencyLogoImg = Image(Source = imageSource, IsVisible = true)
         currencyLogoImg
 #endif
+    let DefaultDesktopWindowSize = 500, 1000