CBitmapDC - An automatic memory DC wrapper

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CBitmapDC is a subclass of CDC. It is a handy little class that provides a memory bitmap device context without having to reinvent the wheel every time you need one.

Example 1

CBitmapDC can be used to make a CBitmap on the fly

1. make a memory bitmap DC by calling CBitmapDC's constructor with the desired bitmap width and height
2. draw in this device context with normal CDC drawing functions
3. call CBitmapDC's Close function, this returns a pointer to the finished CBitmap
4. do whatever you want to do with the CBitmap
5. delete the CBitmap

void CMyView::OnDraw(CDC* pDC)
{
  CBitmapDC bitmapDC(50, 50, pDC);
  bitmapDC.Rectangle(0, 0, 50, 50);
  bitmapDC.MoveTo(0,50);
  bitmapDC.LineTo(50,0);
  CBitmap *pbmp = bitmapDC.Close();
  DrawBitmap(pbmp, pDC, CPoint(10, 10));
  delete pbmp;
}

Example 2

CBitmapDC can be used as a temporary scratchpad

1. make a memory bitmap DC by calling CBitmapDC's constructor with the desired bitmap width and height
2. draw in this device context with normal CDC drawing functions
3. do whatever you want to do e.g. blit the memory DC to screen
4. use the automatic cleanup of CBitmapDC's destructor

void CMyView::OnDraw(CDC* pDC)
{
  CBitmapDC bitmapDC_2(50, 50, pDC);
  bitmapDC_2.Rectangle(0, 0, 50, 50);
  bitmapDC_2.MoveTo(0, 0);
  bitmapDC_2.LineTo(50, 50);
  pDC->BitBlt(200, 10, 50, 50, &bitmapDC_2, 0, 0, SRCCOPY);
}