fixed calling Union() or Offset() on a previously Clear()ed region, also removed some duplicate code (bug 560302 and more)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@15663 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/region.cpp

@@ -66,6 +66,7 @@ public:
 };
 
 #define M_REGION (((wxRegionRefData*)m_refData)->m_region)
+#define M_REGION_OF(rgn) (((wxRegionRefData*)(rgn.m_refData))->m_region)
 
 //-----------------------------------------------------------------------------
 // wxRegion
@@ -146,6 +147,8 @@ void wxRegion::Clear()
 
 bool wxRegion::Offset(wxCoord x, wxCoord y)
 {
+    wxCHECK_MSG( M_REGION, FALSE, _T("invalid wxRegion") );
+
     if ( !x && !y )
     {
         // nothing to do
@@ -164,62 +167,85 @@ bool wxRegion::Offset(wxCoord x, wxCoord y)
     return TRUE;
 }
 
-// Combine rectangle (x, y, w, h) with this.
+// combine another region with this one
-bool wxRegion::Combine(wxCoord x, wxCoord y, wxCoord width, wxCoord height, wxRegionOp op)
+bool wxRegion::Combine(const wxRegion& rgn, wxRegionOp op)
 {
-    AllocExclusive();
+    // we can't use the API functions if we don't have a valid region handle
-
+    if ( !m_refData )
-    HRGN rectRegion = ::CreateRectRgn(x, y, x + width, y + height);
+    {
-
+        // combining with an empty/invalid region works differently depending
-    int mode = 0;
+        // on the operation
         switch ( op )
         {
-        case wxRGN_AND: mode = RGN_AND; break ;
-        case wxRGN_OR: mode = RGN_OR; break ;
-        case wxRGN_XOR: mode = RGN_XOR; break ;
-        case wxRGN_DIFF: mode = RGN_DIFF; break ;
             case wxRGN_COPY:
+            case wxRGN_OR:
+            case wxRGN_XOR:
+                *this = rgn;
+                break;
+
             default:
-            mode = RGN_COPY; break ;
+                wxFAIL_MSG( _T("unknown region operation") );
+                // fall through
+
+            case wxRGN_AND:
+            case wxRGN_DIFF:
+                // leave empty/invalid
+                return FALSE;
+        }
+    }
+    else // we have a valid region
+    {
+        int mode;
+        switch ( op )
+        {
+            case wxRGN_AND:
+                mode = RGN_AND;
+                break;
+
+            case wxRGN_OR:
+                mode = RGN_OR;
+                break;
+
+            case wxRGN_XOR:
+                mode = RGN_XOR;
+                break;
+
+            case wxRGN_DIFF:
+                mode = RGN_DIFF;
+                break;
+
+            default:
+                wxFAIL_MSG( _T("unknown region operation") );
+                // fall through
+
+            case wxRGN_COPY:
+                mode = RGN_COPY;
+                break;
         }
 
-    bool success = ::CombineRgn(M_REGION, M_REGION, rectRegion, mode) != ERROR;
+        if ( ::CombineRgn(M_REGION, M_REGION, M_REGION_OF(rgn), mode) == ERROR )
-    if ( !success )
         {
             wxLogLastError(_T("CombineRgn"));
-    }
 
-    ::DeleteObject(rectRegion);
-
-    return success;
-}
-
-// Union /e region with this.
-bool wxRegion::Combine(const wxRegion& region, wxRegionOp op)
-{
-    if (region.Empty())
             return FALSE;
-
+        }
-    AllocExclusive();
-
-    int mode = 0;
-    switch (op)
-    {
-        case wxRGN_AND: mode = RGN_AND; break ;
-        case wxRGN_OR: mode = RGN_OR; break ;
-        case wxRGN_XOR: mode = RGN_XOR; break ;
-        case wxRGN_DIFF: mode = RGN_DIFF; break ;
-        case wxRGN_COPY:
-        default:
-            mode = RGN_COPY; break ;
     }
 
-    return (ERROR != ::CombineRgn(M_REGION, M_REGION, ((wxRegionRefData*)region.m_refData)->m_region, mode));
+    return TRUE;
+}
+
+// Combine rectangle (x, y, w, h) with this.
+bool wxRegion::Combine(wxCoord x, wxCoord y,
+                       wxCoord width, wxCoord height,
+                       wxRegionOp op)
+{
+    return Combine(wxRegion(x, y, width, height), op);
 }
 
 bool wxRegion::Combine(const wxRect& rect, wxRegionOp op)
 {
-    return Combine(rect.GetLeft(), rect.GetTop(), rect.GetWidth(), rect.GetHeight(), op);
+    return Combine(rect.GetLeft(), rect.GetTop(),
+                   rect.GetWidth(), rect.GetHeight(), op);
 }
 
 //-----------------------------------------------------------------------------