Advanced MFC Programming

Chapter 4. Button
}
pDC,
rect.left,
rect.top,
SRCCOPY
);
memDCImage.BitBlt
(
0,
0,
rect.Width(),
rect.Height(),
&memDC,
0,
0,
SRCINVERT
);
memDCImage.BitBlt
(
0,
0,
rect.Width(),
rect.Height(),
&memDCMask,
0,
0,
SRCAND
);
memDCImage.BitBlt
(
0,
0,
rect.Width(),
rect.Height(),
&memDC,
0,
0,
SRCINVERT
);
pDC->BitBlt
(
rect.left,
rect.top,
rect.Width(),
rect.Height(),
&memDCImage,
0,
0,
SRCCOPY
);
}
memDC.SelectObject(pOld);
if(pBitmapMask != NULL)
{
memDCMask.SelectObject(pOldMask);
memDCImage.SelectObject(pOldImage);
}
Bitmap copy is implemented by calling function CDC::BitBlt(…). This function will copy the selected
bitmap from one DC to another. If there is no mask bitmap, we copy the normal bitmap (selected by memDC)
directly to the target DC (pointed by pDC). Otherwise, first we copy the image pattern from the target device
(pDC) to memory bitmap (selected by memDCImage). Then we copy normal bitmap and mask bitmap
(selected by memDC and memDCMask) to this memory bitmap three times, using different operation modes,
and copy the final result to the target DC (pDC). At last, we select the bitmaps out of DCs.
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