Drawing bitmaps without memory leaks. HELP.

[qedusa]

I'm trying to draw a bitmap image repeatedly. However, it crashes when it's draw the same image about 1,000 times - I suspect due to a memory leak. I need someone to tell me the best way to display a bitmap and then destroy the associated memory immediately afterwards. Any sample code anyone?

 

[tchouch]

You should override OnDraw() Function in Your CWnd-derived class.
An example for a Bitmap with Handle hBitmap (created with CreateBitmap(), CreateDIBitmap() etc.):

HBITMAP AnyFunktion()
{
...
HBITMAP hBitmap = CreateDIBitmap(...); //Get Your Bitmap Handle
...
return hBitmap;
}

void CMyView::OnDraw(CDC* pDC)
{
HDC hdcMem = CreateCompatibleDC(pDC->m_hDC);
if(hdcMem) {
RECT rct;
GetClientRect(&rct);
HGDIOBJ hobj = SelectObject(hdcMem,hBitmap);
if(hobj) {
CPoint pnt = GetScrollPosition( ); //If the Bitmap is biggeras View
BitBlt(pDC->m_hDC, pnt.x, pnt.y, pnt.x + rct.right, pnt.y + rct.bottom, hdcMem, pnt.x, pnt.y, SRCCOPY);
}
DeleteDC(hdcMem);
}
}

Do not forget DeleteObject(hBitmap) after You do not need it more.
Do not create or delete Bitmap in OnDraw() - it makes Your Program slow.

 

[qedusa]

Thanks tchouch, I realized that the problem wasn't my bitmap drawing code but something to do with my [shape] drawing. I'm trying to draw a shape and then a bitmap image on top. When I started to have problems repeating the process I naturally blamed the bitmap!!
However, I have found your tip (example) useful anyway for speeding up the drawing process!!
Thanks