Fix GTK

src/Gtk/Avalonia.Gtk3/Interop/Native.cs

@@ -263,7 +263,7 @@ namespace Avalonia.Gtk3.Interop
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
             public delegate void gtk_window_close(GtkWindow window);
 
-            [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gdk)]
+            [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
             public delegate void gtk_window_set_geometry_hints(GtkWindow window, IntPtr geometry_widget, ref GdkGeometry geometry, GdkWindowHints geom_mask);
 
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gdk)]
@@ -502,6 +502,8 @@ namespace Avalonia.Gtk3.Interop
         public static D.cairo_set_font_size CairoSetFontSize;
         public static D.cairo_move_to CairoMoveTo;
         public static D.cairo_destroy CairoDestroy;
+
+        public static D.gtk_window_set_geometry_hints GtkWindowSetGeometryHints;
         public const int G_TYPE_OBJECT = 80;
     }
 
@@ -739,19 +741,19 @@ namespace Avalonia.Gtk3.Interop
     }
 
     [StructLayout(LayoutKind.Sequential)]
-    struct GdkGeometry
+    public struct GdkGeometry
     {
-        gint min_width;
-        gint min_height;
-        gint max_width;
-        gint max_height;
-        gint base_width;
-        gint base_height;
-        gint width_inc;
-        gint height_inc;
-        gdouble min_aspect;
-        gdouble max_aspect;
-        gint win_gravity;
+        public gint min_width;
+        public gint min_height;
+        public gint max_width;
+        public gint max_height;
+        public gint base_width;
+        public gint base_height;
+        public gint width_inc;
+        public gint height_inc;
+        public gdouble min_aspect;
+        public gdouble max_aspect;
+        public gint win_gravity;
     }
 
     enum GdkWindowHints

src/Gtk/Avalonia.Gtk3/WindowBaseImpl.cs

@@ -439,6 +439,15 @@ namespace Avalonia.Gtk3
         {
             if (GtkWidget.IsClosed)
                 return;
+
+            GdkGeometry geometry = new GdkGeometry();
+            geometry.min_width = MinWidth > 0 ? (int)MinWidth : -1;
+            geometry.min_height = MinHeight > 0 ? (int)MinHeight : -1;
+            geometry.max_width = !Double.IsInfinity(MaxWidth) && MaxWidth > 0 ? (int)MaxWidth : 999999;
+            geometry.max_height = !Double.IsInfinity(MaxHeight) && MaxHeight > 0 ? (int)MaxHeight : 999999;
+            
+            Native.GtkWindowSetGeometryHints(GtkWidget, IntPtr.Zero, ref geometry, GdkWindowHints.GDK_HINT_MIN_SIZE | GdkWindowHints.GDK_HINT_MAX_SIZE);                
+
             Native.GtkWindowResize(GtkWidget, (int)value.Width, (int)value.Height);
             if (OverrideRedirect)
             {