Update wxStaticBitmap in wxMSW on DPI change

Use the appropriately sized bitmap when the resolution changes.

include/wx/msw/statbmp.h

@@ -112,7 +112,9 @@ private:
     // can we leave it to it)
     void DoPaintManually(wxPaintEvent& event);
 
+    // event handlers
     void WXHandleSize(wxSizeEvent& event);
+    void WXHandleDPIChanged(wxDPIChangedEvent& event);
 
     // return the size of m_icon or the appropriate size of m_bitmapBundle at
     // the current DPI scaling (may still be invalid of both of them are)

src/msw/statbmp.cpp

@@ -45,6 +45,7 @@
 
 wxBEGIN_EVENT_TABLE(wxStaticBitmap, wxStaticBitmapBase)
     EVT_SIZE(wxStaticBitmap::WXHandleSize)
+    EVT_DPI_CHANGED(wxStaticBitmap::WXHandleDPIChanged)
 wxEND_EVENT_TABLE()
 
 // ===========================================================================
@@ -190,6 +191,16 @@ void wxStaticBitmap::WXHandleSize(wxSizeEvent& event)
     event.Skip();
 }
 
+void wxStaticBitmap::WXHandleDPIChanged(wxDPIChangedEvent& event)
+{
+    // Icons only exist in a single resolution, so don't bother updating in
+    // this case.
+    if ( !m_icon.IsOk() && m_bitmapBundle.IsOk() )
+        DoUpdateImage(wxSize(), false /* not using an icon */);
+
+    event.Skip();
+}
+
 void wxStaticBitmap::DoPaintManually(wxPaintEvent& WXUNUSED(event))
 {
     wxPaintDC dc(this);