Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
?
Solved

Pointer to bits of bitmap

Posted on 2004-04-14
2
Medium Priority
?
635 Views
Last Modified: 2008-03-03
I have this:
    hDCMem = CreateCompatibleDC(NULL);

    RECT rect;

    GetWindowRect(hWnd, & rect);

    hBmp = NULL;

    {
        HDC hDC = GetDC(hWnd);
        hBmp = CreateCompatibleBitmap(hDC, rect.right - rect.left, rect.bottom - rect.top);
        ReleaseDC(hWnd, hDC);
    }
      hOld = SelectObject(hDCMem, hBmp);


How can I get a pointer the bits that make up hBmp?
0
Comment
Question by:rossryan
2 Comments
 
LVL 48

Accepted Solution

by:
AlexFM earned 2000 total points
ID: 10830609
Asked in my last post to your previous question: replace CreateCompatibleBitmap with CreateDIBSection.
Bits of the bitmap created by CreateDIBSection may be accessed by GetBitmapBits and SetBitmapBits functions. If you need direct pointer to bitmap bits, it is returned as output parameter of CreateDIBSection function. Except of this, GetObject API may be applied to HBITMAP, it fills the BITMAP structure. BITMAP::bmBits is pointer to bitmap bits.
If bitmap is created by CreateCompatibleDC, BITMAP::bmBits is NULL. If it is created by CreateDIBSection, this pointer is available.

So, replace this line:

hBmp = CreateCompatibleBitmap(hDC, rect.right - rect.left, rect.bottom - rect.top);

with these:

   int nWidth = rect.right - rect.left;
   int nHeight = rect.bottom - rect.top;
   LPBITMAPINFO lpbi;

    lpbi = (LPBITMAPINFO) new BYTE[sizeof(BITMAPINFOHEADER) + (256 * sizeof(RGBQUAD))];
    lpbi->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
    lpbi->bmiHeader.biWidth = nWidth;
    lpbi->bmiHeader.biHeight = nHeight;
    lpbi->bmiHeader.biPlanes = 1;
    lpbi->bmiHeader.biBitCount = 32; //24;
    lpbi->bmiHeader.biCompression = BI_RGB;
    lpbi->bmiHeader.biSizeImage = nWidth * nHeight; //    WIDTHBYTES((DWORD)nWidth * 8) * nHeight;
    lpbi->bmiHeader.biXPelsPerMeter = 0;
    lpbi->bmiHeader.biYPelsPerMeter = 0;
    lpbi->bmiHeader.biClrUsed = 0;
    lpbi->bmiHeader.biClrImportant = 0;

    BYTE* pTmp;

    hBmp = CreateDIBSection(
        NULL,
        lpbi,
        DIB_RGB_COLORS,
        (void **)&pTmp,
        NULL,
        0 );

    delete[] lpbi;
0
 

Author Comment

by:rossryan
ID: 10831160
Got ya, I posted this before you replied.
0

Featured Post

Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction This article is a continuation of the C/C++ Visual Studio Express debugger series. Part 1 provided a quick start guide in using the debugger. Part 2 focused on additional topics in breakpoints. As your assignments become a little more …
This article shows you how to optimize memory allocations in C++ using placement new. Applicable especially to usecases dealing with creation of large number of objects. A brief on problem: Lets take example problem for simplicity: - I have a G…
The goal of the tutorial is to teach the user how to use functions in C++. The video will cover how to define functions, how to call functions and how to create functions prototypes. Microsoft Visual C++ 2010 Express will be used as a text editor an…
The goal of the video will be to teach the user the difference and consequence of passing data by value vs passing data by reference in C++. An example of passing data by value as well as an example of passing data by reference will be be given. Bot…

578 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question