From bd835ee452213d1252750daa495344b099b09329 Mon Sep 17 00:00:00 2001
From: Paul Cornett <paulcor@users.noreply.github.com>
Date: Sat, 1 Aug 2020 21:23:34 -0700
Subject: [PATCH] Fix a sizing/layout problem with GTK3

Relying on "check-resize" to detect when a "size-allocate" is in progess is
insufficient, resulting in the possibility of a window ending up with the wrong
size or position after inital layout. Using our existing "size-allocate"
handlers should be enough to detect the cases we care about.
See #18865
---
 src/gtk/toplevel.cpp |  6 ++++++
 src/gtk/window.cpp   | 32 ++++++--------------------------
 2 files changed, 12 insertions(+), 26 deletions(-)

diff --git a/src/gtk/toplevel.cpp b/src/gtk/toplevel.cpp
index 2bbdb79e9c..c43add8016 100644
--- a/src/gtk/toplevel.cpp
+++ b/src/gtk/toplevel.cpp
@@ -57,6 +57,7 @@ static wxTopLevelWindowGTK *g_activeFrame = NULL;
 
 extern wxCursor g_globalCursor;
 extern wxCursor g_busyCursor;
+extern bool g_inSizeAllocate;
 
 #ifdef GDK_WINDOWING_X11
 // Whether _NET_REQUEST_FRAME_EXTENTS support is working
@@ -240,6 +241,9 @@ size_allocate(GtkWidget*, GtkAllocation* alloc, wxTopLevelWindowGTK* win)
     if (win->m_clientWidth  != alloc->width ||
         win->m_clientHeight != alloc->height)
     {
+        const bool save_inSizeAllocate = g_inSizeAllocate;
+        g_inSizeAllocate = true;
+
         win->m_clientWidth  = alloc->width;
         win->m_clientHeight = alloc->height;
 
@@ -272,6 +276,8 @@ size_allocate(GtkWidget*, GtkAllocation* alloc, wxTopLevelWindowGTK* win)
             win->HandleWindowEvent(event);
         }
         // else the window is currently unmapped, don't generate size events
+
+        g_inSizeAllocate = save_inSizeAllocate;
     }
 }
 }
diff --git a/src/gtk/window.cpp b/src/gtk/window.cpp
index e0345ada38..4e33c1ff06 100644
--- a/src/gtk/window.cpp
+++ b/src/gtk/window.cpp
@@ -225,8 +225,8 @@ int          g_lastButtonNumber = 0;
 
 #ifdef __WXGTK3__
 static GList* gs_sizeRevalidateList;
-static bool gs_inSizeAllocate;
 #endif
+bool g_inSizeAllocate;
 
 #if GTK_CHECK_VERSION(3,14,0)
     #define wxGTK_HAS_GESTURES_SUPPORT
@@ -2279,9 +2279,12 @@ size_allocate(GtkWidget* WXUNUSED_IN_GTK2(widget), GtkAllocation* alloc, wxWindo
         win->m_width  = a.width;
         win->m_height = a.height;
         {
+            const bool save_inSizeAllocate = g_inSizeAllocate;
+            g_inSizeAllocate = true;
             wxSizeEvent event(win->GetSize(), win->GetId());
             event.SetEventObject(win);
             win->GTKProcessEvent(event);
+            g_inSizeAllocate = save_inSizeAllocate;
         }
     }
 }
@@ -2325,22 +2328,6 @@ static void frame_clock_layout(GdkFrameClock*, wxWindow* win)
 }
 #endif // GTK_CHECK_VERSION(3,8,0)
 
-#ifdef __WXGTK3__
-//-----------------------------------------------------------------------------
-// "check-resize"
-//-----------------------------------------------------------------------------
-
-static void check_resize(GtkContainer*, wxWindow*)
-{
-    gs_inSizeAllocate = true;
-}
-
-static void check_resize_after(GtkContainer*, wxWindow*)
-{
-    gs_inSizeAllocate = false;
-}
-#endif // __WXGTK3__
-
 } // extern "C"
 
 void wxWindowGTK::GTKHandleRealized()
@@ -2905,13 +2892,6 @@ void wxWindowGTK::PostCreation()
         g_signal_connect(m_wxwindow ? m_wxwindow : m_widget, "size_allocate",
             G_CALLBACK(size_allocate), this);
     }
-#ifdef __WXGTK3__
-    else
-    {
-        g_signal_connect(m_widget, "check-resize", G_CALLBACK(check_resize), this);
-        g_signal_connect_after(m_widget, "check-resize", G_CALLBACK(check_resize_after), this);
-    }
-#endif
 
 #if GTK_CHECK_VERSION(2, 8, 0)
     if ( wx_is_at_least_gtk2(8) )
@@ -3736,7 +3716,7 @@ void wxWindowGTK::DoMoveWindow(int x, int y, int width, int height)
         pizza->move(m_widget, x, y, width, height);
         if (
 #ifdef __WXGTK3__
-            !gs_inSizeAllocate &&
+            !g_inSizeAllocate &&
 #endif
             gtk_widget_get_visible(m_widget))
         {
@@ -3753,7 +3733,7 @@ void wxWindowGTK::DoMoveWindow(int x, int y, int width, int height)
     // size-allocate can generate wxSizeEvent and size event handlers often
     // call SetSize(), directly or indirectly. It should be fine to call
     // gtk_widget_size_allocate() immediately in this case.
-    if (gs_inSizeAllocate && gtk_widget_get_visible(m_widget) && width > 0 && height > 0)
+    if (g_inSizeAllocate && gtk_widget_get_visible(m_widget) && width > 0 && height > 0)
     {
         // obligatory size request before size allocate to avoid GTK3 warnings
         GtkRequisition req;