Correct erasing of background behind controls in a toolbar in wxMSW.

We need to handle WM_PRINTCLIENT in wxToolBar itself as the default handler
for this message forwards to WM_ERASEBKGND of the parent window and our
handler for that message only erases the client part of the window, in wx
sense, i.e. including a relatively big vertical offset accounting for the
toolbar. This means that when we get WM_PRINTCLIENT from the embedded control
drawing code, we don't erase anything at all as the control rectangle height
is smaller than the offset.

This fix is not perfect as ideally the existing MSWGetBgBrushForChild() should
be taken into account automatically by the default MSWPrintChild()
implementation but at least it fixes the ugly visual artefacts.

Closes #12307.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74757 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

diff --git a/src/msw/toolbar.cpp b/src/msw/toolbar.cpp
index ecaa2b17efbaf98b66c99a13f301b55bffecdeeb..c292bb77de06b529c24b93406989fe6208ffbf51 100644 (file)
--- a/src/msw/toolbar.cpp
+++ b/src/msw/toolbar.cpp
@@ -1948,6 +1948,10 @@ WXLRESULT wxToolBar::MSWWindowProc(WXUINT nMsg, WXWPARAM wParam, WXLPARAM lParam
                 return 0;
             break;
 #endif // wxHAS_MSW_BACKGROUND_ERASE_HOOK
+
+        case WM_PRINTCLIENT:
+            wxFillRect(GetHwnd(), (HDC)wParam, MSWGetToolbarBgBrush());
+            return 1;
     }
 
     return wxControl::MSWWindowProc(nMsg, wParam, lParam);