From 6f888df4740b9014f4a3eeaba5aac64e84358071 Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Sat, 24 Apr 2021 14:56:49 +0100
Subject: [PATCH] Restore button size calculation when not using manifest in
 wxMSW

This fixes regression introduced in de10f054c4 (Improve calculating
wxButton best size under wxMSW, 2021-04-08) which didn't check whether
BCM_GETIDEALSIZE succeeded -- as we must do, because in some situations
(when using very old systems or not using a manifest even under newer
ones), it does indeed fail.
---
 src/msw/anybutton.cpp | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/src/msw/anybutton.cpp b/src/msw/anybutton.cpp
index edac3edad1..9310e33f1a 100644
--- a/src/msw/anybutton.cpp
+++ b/src/msw/anybutton.cpp
@@ -580,17 +580,23 @@ wxSize wxAnyButton::DoGetBestSize() const
 
     wxSize size;
 
-    // BCM_GETIDEALSIZE works properly only it there is a text label in the button.
-    if ( !IsOwnerDrawn() && ShowsLabel() )
+    // The preferred way is to use BCM_GETIDEALSIZE, but it only works properly
+    // if there is a text label in the button and can't be used under old
+    // systems or without a manifest.
+    if ( !IsOwnerDrawn() && ShowsLabel() &&
+            wxGetWinVersion() >= wxWinVersion_Vista )
     {
         SIZE idealSize = { 0, 0 };
-        ::SendMessage(GetHwnd(), BCM_GETIDEALSIZE, 0, (LPARAM)&idealSize);
-        size.Set(idealSize.cx, idealSize.cy);
+        if ( ::SendMessage(GetHwnd(), BCM_GETIDEALSIZE, 0, (LPARAM)&idealSize) )
+            size.Set(idealSize.cx, idealSize.cy);
 
-        if ( m_imageData )
-            AdjustForBitmapMargins(size);
+            if ( m_imageData )
+                AdjustForBitmapMargins(size);
     }
-    else
+
+    // If we failed to set the size using BCM_GETIDEALSIZE above, determine it
+    // ourselves.
+    if ( size == wxSize() )
     {
         // Account for the text part if we have it.
         if ( ShowsLabel() )