Merge branch 'aui-repaint'

Fix some wxAUI repaint problems and switch to using live resize
everywhere by default.

See #24166.

interface/wx/aui/framemanager.h

@@ -45,12 +45,14 @@ enum wxAuiManagerOption
     wxAUI_MGR_NO_VENETIAN_BLINDS_FADE  = 1 << 7,
     /// When a docked pane is resized, its content is refreshed in live (instead of moving
     /// the border alone and refreshing the content at the end).
+    /// Since wxWidgets 3.3.0 this flag is included in the default flags.
     wxAUI_MGR_LIVE_RESIZE              = 1 << 8,
     /// Default behaviour.
     wxAUI_MGR_DEFAULT = wxAUI_MGR_ALLOW_FLOATING |
                         wxAUI_MGR_TRANSPARENT_HINT |
                         wxAUI_MGR_HINT_FADE |
-                        wxAUI_MGR_NO_VENETIAN_BLINDS_FADE
+                        wxAUI_MGR_NO_VENETIAN_BLINDS_FADE |
+                        wxAUI_MGR_LIVE_RESIZE
 };
 
 /**
@@ -144,7 +146,11 @@ enum wxAuiManagerOption
            docking hint immediately.
     @style{wxAUI_MGR_LIVE_RESIZE}
            When a docked pane is resized, its content is refreshed in live (instead of moving
-           the border alone and refreshing the content at the end).
+           the border alone and refreshing the content at the end). Note that
+           this flag is included in wxAUI_MGR_DEFAULT and so needs to be
+           explicitly turned off if you don't need. Also note that it is
+           always enabled in wxGTK3 and wxOSX ports as non-live resizing is not
+           implemented in them.
     @style{wxAUI_MGR_DEFAULT}
            Default behaviour, combines: wxAUI_MGR_ALLOW_FLOATING | wxAUI_MGR_TRANSPARENT_HINT |
            wxAUI_MGR_HINT_FADE | wxAUI_MGR_NO_VENETIAN_BLINDS_FADE.
@@ -215,12 +221,16 @@ public:
         If this function returns true, ::wxAUI_MGR_LIVE_RESIZE flag is ignored
         and live resize is always used, whether it's specified or not.
 
-        Currently this is the case for wxOSX and wxGTK3 ports, as live resizing
-        is the only implemented method there.
+        Currently this is the case for wxOSX and wxGTK3 when using Wayland, as
+        live resizing is the only implemented method there. See
+        wxClientDC::CanBeUsedForDrawing() for more details.
+
+        @param window The associated window, may be null (this parameter was
+            added in wxWidgets 3.3.0)
 
         @since 3.1.4
      */
-    static bool AlwaysUsesLiveResize();
+    static bool AlwaysUsesLiveResize(const wxWindow* window);
 
     /**
         This function is used by controls to calculate the drop hint rectangle.

interface/wx/dcclient.h

@@ -63,12 +63,13 @@ public:
     window from outside an EVT_PAINT() handler in some ports, this does @em not
     work on most of the platforms: neither wxOSX nor wxGTK with GTK 3 Wayland
     backend support this at all, so drawing using wxClientDC simply doesn't
-    have any effect there, while wxMSW doesn't support using it for composited
-    windows, so wxWindow::MSWDisableComposited() must be called to allow it to
-    work. The only supported way of drawing on a window is via wxPaintDC. To
-    redraw a small part of the window, use wxWindow::RefreshRect() to
-    invalidate just this part and check wxWindow::GetUpdateRegion() in the
-    paint event handler to redraw this part only.
+    have any effect there. CanBeUsedForDrawing() can be used to determine
+    whether wxClientDC can be used for drawing in the current environment, but
+    it is recommended to only draw on the window using wxPaintDC, as this is
+    guaranteed to work everywhere. To redraw a small part of the window, use
+    wxWindow::RefreshRect() to invalidate just this part and check
+    wxWindow::GetUpdateRegion() in the paint event handler to redraw this part
+    only.
 
     wxClientDC objects should normally be constructed as temporary stack
     objects, i.e. don't store a wxClientDC object.
@@ -88,6 +89,23 @@ public:
         Constructor. Pass a pointer to the window on which you wish to paint.
     */
     wxClientDC(wxWindow* window);
+
+    /**
+        Return true if drawing on wxClientDC actually works.
+
+        In many environments (currently this includes wxGTK when using Wayland
+        backend, wxMSW when using double buffering and wxOSX in all cases),
+        wxClientDC can be only used for obtaining information about the device
+        context, but not for actually drawing on it. Portable code should avoid
+        using wxClientDC completely, as explained in the class documentation,
+        but it is also possible to optionally use it only when it does work,
+        i.e. when this function returns @true.
+
+        @param window The window that would be used with wxClientDC.
+
+        @since 3.3.0
+     */
+    static bool CanBeUsedForDrawing(const wxWindow* window);
 };
 
 

interface/wx/splitter.h

@@ -142,6 +142,20 @@ public:
     */
     virtual ~wxSplitterWindow();
 
+    /**
+        Returns true if splitter always behaves as if wxSP_LIVE_UPDATE were
+        specified.
+
+        This function returns true if non-live update mode is not supported and
+        live update is always used, even if wxSP_LIVE_UPDATE was not explicitly
+        specified.
+
+        @see wxClientDC::CanBeUsedForDrawing()
+
+        @since 3.3.0
+    */
+    bool AlwaysUsesLiveUpdate() const;
+
     /**
         Creation function, for two-step construction.
         See wxSplitterWindow() for details.