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Working with 32BPP DIBSection using HDC regardless of display settings

Hello,

I have a DIB section, and I want to use standard GDI functions like LineTo, BitBlt, AlphaBlend etc. to work with it. Hovewer, I don't want to be dependent on current display settings. I would like to create DC not compatible with any device, but with memory, so I can use the full power of 32BPP bitmaps, when user has for example 256 color display mode. How to do that?

VC++ 6.0 (MFC Dialog App), SP6, PSDK Feb 2003, WinXP

Thanks.

marcodalzotto

Do you have a surce code to work on?

JiriNovotny

ASKER

Sure, here is the DIB section creation:

BITMAPINFO m_tBI;
HDC m_hDC;
HBITMAP m_hDIB;
DWORD *m_pData;
HBITMAP m_hOldBmp;
......

// Create device context
m_hDC = CreateCompatibleDC(NULL);
if(m_hDC != NULL)
{
// Init struct
ZeroMemory(&m_tBI, sizeof(m_tBI));
m_tBI.bmiHeader.biSize = sizeof(m_tBI.bmiHeader);
m_tBI.bmiHeader.biPlanes = 1;
m_tBI.bmiHeader.biBitCount = 32;
m_tBI.bmiHeader.biCompression = BI_RGB;
m_tBI.bmiHeader.biWidth = dwWidth;
m_tBI.bmiHeader.biHeight = dwHeight;
m_tBI.bmiHeader.biSizeImage = dwWidth * dwHeight * 4;

// Create DIB section
m_hDIB = CreateDIBSection(m_hDC, &m_tBI, DIB_RGB_COLORS, (LPVOID*)&m_pData, 0, 0);
if(m_hDIB != NULL)
{
// Select DIB into device context
m_hOldBmp = (HBITMAP)SelectObject(m_hDC, m_hDIB);
// Guarantee that GDI has completed any drawing to a bitmap
GdiFlush();
// Save sizes
m_dwWidth = dwWidth;
m_dwHeight = dwHeight;
// Validate image
m_bValid = TRUE;
// Return success
return TRUE;
}
// Error, so clean up
DeleteDC(m_hDC);
}

As you can see, I'm using current display DC. Hovewer, I want to not use such a DC, but 'memory' DC. I'm sure you understand.

JiriNovotny

ASKER

Is it really so hard that nobody knows?

ASKER CERTIFIED SOLUTION

marcodalzotto

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