CODEWITHSUNDEEP
bitmapdirect2dc++builder-xe7
Mike Versteeg
Mike Versteeg

Reputation: 1623

Destroy Direct2D bitmap?

I'm using C++ Builder XE7. Whenever a form resizes I need to rebuild a D2D bitmap, which I create with CreateBitmap(). As this will quickly eat up all video memory, I want to destroy the previous bitmap before creating a new one. Oddly enough I cannot find any information how to destroy this _di_ID2D1Bitmap. I tried the Release() method but that just gives me an AV in line 291 of systobj.h.

What is the proper way to destroy a _di_ID2D1Bitmap?

Thanks.

Upvotes: 0

Views: 600

Answers (1)

Peter Kostov
Peter Kostov

Reputation: 951

_di_ID2D1Bitmap is a DelphiInterface. An interface reference in Delphi is a pointer to pointer to an IMT. So, a variable of _di_ID2D1Bitmap type is a pointer.

You don't have to free it manually, because there is an automatic reference counting - ie - when there are no references left, it will be freed automatically. You may check the IInterface._AddRef and IInterface._Release methods.

In short, if you have a pointer P holding just one reference to your ID2D1Bitmap (ie _di_ID2D1Bitmap), when you pass it to the CreateBitmap() it will acquire a ref to the new bitmap while the old one will became with 0 references and will be freed.

Here are some useful reads:

Upvotes: 2

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