// the same native GDI object
// ----------------------------------------------------------------------------
-class WXDLLIMPEXP_CORE wxGDIRefData: public wxObjectRefData { };
+class WXDLLIMPEXP_CORE wxGDIRefData : public wxObjectRefData
+{
+public:
+ // Default ctor which needs to be defined just because we use
+ // wxDECLARE_NO_COPY_CLASS() below.
+ wxGDIRefData() { }
+
+ // override this in the derived classes to check if this data object is
+ // really fully initialized
+ virtual bool IsOk() const { return true; }
+
+private:
+ wxDECLARE_NO_COPY_CLASS(wxGDIRefData);
+};
// ----------------------------------------------------------------------------
-// wxGDIObject
+// wxGDIObject: base class for bitmaps, pens, brushes, ...
// ----------------------------------------------------------------------------
-class WXDLLIMPEXP_CORE wxGDIObject: public wxObject
+class WXDLLIMPEXP_CORE wxGDIObject : public wxObject
{
public:
+ // checks if the object can be used
+ virtual bool IsOk() const
+ {
+ // the cast here is safe because the derived classes always create
+ // wxGDIRefData objects
+ return m_refData && static_cast<wxGDIRefData *>(m_refData)->IsOk();
+ }
+
+ // don't use in the new code, use IsOk() instead
bool IsNull() const { return m_refData == NULL; }
+ // older version, for backwards compatibility only (but not deprecated
+ // because it's still widely used)
+ bool Ok() const { return IsOk(); }
+
#if defined(__WXMSW__) || defined(__WXPM__) || defined(__WXPALMOS__)
// Creates the resource
virtual bool RealizeResource() { return false; }
virtual WXHANDLE GetResourceHandle() const { return 0; }
#endif // defined(__WXMSW__) || defined(__WXPM__)
+protected:
+ // replace base class functions using wxObjectRefData with our own which
+ // use wxGDIRefData to ensure that we always work with data objects of the
+ // correct type (i.e. derived from wxGDIRefData)
+ virtual wxObjectRefData *CreateRefData() const
+ {
+ return CreateGDIRefData();
+ }
+
+ virtual wxObjectRefData *CloneRefData(const wxObjectRefData *data) const
+ {
+ return CloneGDIRefData(static_cast<const wxGDIRefData *>(data));
+ }
+
+ virtual wxGDIRefData *CreateGDIRefData() const = 0;
+ virtual wxGDIRefData *CloneGDIRefData(const wxGDIRefData *data) const = 0;
+
DECLARE_DYNAMIC_CLASS(wxGDIObject)
};
-#endif
- // _WX_GDIOBJ_H_BASE_
+#endif // _WX_GDIOBJ_H_BASE_