Advanced MFC Programming

Chapter 10. Bitmap
lpLogPal->palVersion=0x300;
lpLogPal->palNumEntries=nSizeCT;
for(i=0; ipalPalEntry[i].peRed=lpBi->bmiColors[i].rgbRed;
lpLogPal->palPalEntry[i].peGreen=lpBi->bmiColors[i].rgbGreen;
lpLogPal->palPalEntry[i].peBlue=lpBi->bmiColors[i].rgbBlue;
lpLogPal->palPalEntry[i].peFlags=NULL;
}
}
VERIFY(pPalDraw->CreatePalette(lpLogPal));
delete [](BYTE *)lpLogPal;
pPalOld=dc.SelectPalette(pPalDraw, FALSE);
dc.RealizePalette();
……
CleanUp();
hBmp=::CreateDIBSection
(
dc.GetSafeHdc(),
lpBi,
DIB_RGB_COLORS,
(void **)&pBits,
NULL,
0
);
memcpy
(
(LPSTR)pBits,
(LPSTR)lpBi+sizeof(BITMAPINFOHEADER)+nSizeCT*sizeof(RGBQUAD),
lpBi->bmiHeader.biSizeImage
);
ASSERT(hBmp);
m_bmpDraw.Attach(hBmp);
Please note that function CGDIView::CleanUp() is called before the bitmap is created. After the DIB
section is created, we use the DIB data passed through hData parameter to initialize the image. The buffers
that store DIB bit values are pointed by pointer pBits. We can use it to edit the image pixels directly, there
is no need to convert between DDB and DIB foramts any more.
After the bitmap is loaded, we need to create the mask bitmap, memory bitmap, and theree memory
DCs. We also need to select the bitmaps and the logical palette into the DCs if necessary:
……
m_dcMem.CreateCompatibleDC(&dc);
m_dcMemMask.CreateCompatibleDC(&dc);
m_dcMemBS.CreateCompatibleDC(&dc);
ASSERT(m_dcMem.GetSafeHdc());
ASSERT(m_dcMemMask.GetSafeHdc());
ASSERT(m_dcMemBS.GetSafeHdc());
if(nSizeCT != 0)
{
m_pPalOld=m_dcMem.SelectPalette(pPalDraw, FALSE);
m_pPalMaskOld=m_dcMemMask.SelectPalette(pPalDraw, FALSE);
m_pPalBSOld=m_dcMemBS.SelectPalette(pPalDraw, FALSE);
}
m_bmpMask.CreateCompatibleBitmap
(
&dc,
lpBi->bmiHeader.biWidth,
lpBi->bmiHeader.biHeight
);
m_bmpBS.CreateCompatibleBitmap
(
&dc,
lpBi->bmiHeader.biWidth,
lpBi->bmiHeader.biHeight
);
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