diff --git a/Common/Gfx/Canvas.h b/Common/Gfx/Canvas.h
index b8afa649..262179e7 100644
--- a/Common/Gfx/Canvas.h
+++ b/Common/Gfx/Canvas.h
@@ -25,10 +25,9 @@
 
 namespace Gfx {
 
-class Canvas
+class __declspec(novtable) Canvas
 {
 public:
-	Canvas();
 	virtual ~Canvas();
 
 	int GetW() const { return m_W; }
@@ -72,6 +71,8 @@ public:
 	virtual void FillRectangle(Gdiplus::Rect& rect, const Gdiplus::SolidBrush& brush) = 0;
 
 protected:
+	Canvas();
+
 	int m_W;
 	int m_H;
 
diff --git a/Common/Gfx/TextFormat.h b/Common/Gfx/TextFormat.h
index 29a733ea..cd490292 100644
--- a/Common/Gfx/TextFormat.h
+++ b/Common/Gfx/TextFormat.h
@@ -37,10 +37,9 @@ enum class VerticalAlignment : BYTE
 	Bottom
 };
 
-class TextFormat
+class __declspec(novtable) TextFormat
 {
 public:
-	TextFormat();
 	virtual ~TextFormat();
 
 	virtual bool IsInitialized() = 0;
@@ -54,6 +53,9 @@ public:
 	virtual void SetVerticalAlignment(VerticalAlignment alignment);
 	VerticalAlignment GetVerticalAlignment() { return m_VerticalAlignment; }
 
+protected:
+	TextFormat();
+
 private:
 	TextFormat(const TextFormat& other) {}