GDI+ cause the application freeze

[Tal Rashas Guardianship]

I have got a trouble of GDI+, my code is like this: CPaintDC dc(this); // device context for painting CRect rect; GetClientRect(&rect); CDC dcMem; dcMem.CreateCompatibleDC(&dc); CBitmap bitmap; bitmap.CreateCompatibleBitmap(&dc, rect.Width(), rect.Height()); dcMem.SelectObject(&bitmap); Graphics graphics(dcMem.m_hDC); SolidBrush brushBKGnd(Color(0,0,0)); //freeze at here graphics.FillRectangle(&brushBKGnd, Rect(rect.left, rect.top, rect.Width(), rect.Height())); The code will freeze at the last line, I don't know why, please help me.

[Stuart Dootson]

Well - your code is OK - I've just tried it and it works even if you don't startup GDI+ properly. You do have to remember to blit the bitmap to the window DC to see anything, mind. So - your code's (superficially) OK - maybe there's something about your setup that's not quite right? What are the co-ordinates of your rectangle? What happens if you paint to dc rather than dcMem?

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

[Tal Rashas Guardianship]

I have tried to test the parameters which were sent to FillRectangle function, I found that when they are big numbers(i.e, 200,000), the calling to FillRectangle will freeze. But from my code, the value of CRect is got from API GetClientRect, does this function have some possibility to fail?

[Stuart Dootson]

Can I suggest you set a breakpoint on FillRectangle and see what the client rect value is?

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

[Tal Rashas Guardianship]

No，I didn't set breakpoint, I just create a CRect object with large paramaters: CRect rect(0, 0, 200000, 200000); //Disable this line //GetClientRect(&rect);

[Stuart Dootson]

No - get rid of those test parameters and try to find what the rectangle co-ordinates are when the call freezes when the rectangle is derived from the client rect.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

[Tal Rashas Guardianship]

I see, thanks for your mention

[Tal Rashas Guardianship]

Hi there. The reason is clear. It's because that I called the GDI+ APIs in another thread, and GDI+ doesn't support multi-thread calling