windowscodecs: Distinguish interface and implementation pointer for IcnsEncoder.

dlls/windowscodecs/icnsformat.c

@@ -179,7 +179,7 @@ static ULONG WINAPI IcnsFrameEncode_Release(IWICBitmapFrameEncode *iface)
         if (This->icns_image != NULL)
             HeapFree(GetProcessHeap(), 0, This->icns_image);
 
-        IUnknown_Release((IUnknown*)This->encoder);
+        IWICBitmapFrameEncode_Release(&This->encoder->IWICBitmapFrameEncode_iface);
         HeapFree(GetProcessHeap(), 0, This);
     }
 
@@ -489,7 +489,7 @@ static HRESULT WINAPI IcnsEncoder_QueryInterface(IWICBitmapEncoder *iface, REFII
     if (IsEqualIID(&IID_IUnknown, iid) ||
         IsEqualIID(&IID_IWICBitmapEncoder, iid))
     {
-        *ppv = This;
+        *ppv = &This->IWICBitmapEncoder_iface;
     }
     else
     {
@@ -639,7 +639,7 @@ static HRESULT WINAPI IcnsEncoder_CreateNewFrame(IWICBitmapEncoder *iface,
     frameEncode->committed = FALSE;
     *ppIFrameEncode = &frameEncode->IWICBitmapFrameEncode_iface;
     This->outstanding_commits++;
-    IUnknown_AddRef((IUnknown*)This);
+    IWICBitmapEncoder_AddRef(&This->IWICBitmapEncoder_iface);
 
 end:
     LeaveCriticalSection(&This->lock);
@@ -725,8 +725,8 @@ HRESULT IcnsEncoder_CreateInstance(REFIID iid, void** ppv)
     InitializeCriticalSection(&This->lock);
     This->lock.DebugInfo->Spare[0] = (DWORD_PTR)(__FILE__ ": IcnsEncoder.lock");
 
-    ret = IUnknown_QueryInterface((IUnknown*)This, iid, ppv);
-    IUnknown_Release((IUnknown*)This);
+    ret = IWICBitmapEncoder_QueryInterface(&This->IWICBitmapEncoder_iface, iid, ppv);
+    IWICBitmapEncoder_Release(&This->IWICBitmapEncoder_iface);
 
     return ret;
 }