Thread: Loading a bmp from a string?

  1. #1
    60% Braindead
    Join Date
    Dec 2005

    Loading a bmp from a string?

    Hey, I've been messing with bitmaps for a day or so now, and it gets very montonous to add bitmap names to the resource file. I was wondering if theres some way to copy the bitmap contents to a constant string, then load it? That way theres no need for resources or external files.


    (oddly enough this doesnt work:

    const char TESTBITMAP1[] = "*Bitmap information*"
       ScreenDisplay_Object = (HBITMAP)LoadImage(GetModuleHandle(NULL), TESTBITMAP1, IMAGE_BITMAP, 0, 0, LR_DEFAULTCOLOR);
       if(ScreenDisplay_Object == NULL)
        MessageBox(hwnd, "Could not load object!", "Error", MB_OK | MB_ICONEXCLAMATION);
    Theres more code to it, but it shouldent turn out as null, but it always does?)
    Last edited by Blackroot; 09-01-2006 at 10:54 PM.
    Error W8057 C:\\Life.cpp: Invalid number of arguments in function run(Brain *)

  2. #2
    Registered User Tonto's Avatar
    Join Date
    Jun 2005
    New York
    You could statically encode a BITMAP structure and CreateBitmapIndirect for the handle. But why do you care if there are resources?

  3. #3
    60% Braindead
    Join Date
    Dec 2005
    I dont really, I just like keeping my options open. Its also quicker for me to just copy the bitmap to a constant char rather than a res file & definition.

    It says on MSDN CreateBitmapIndirect should be used for monochrome bitmaps. Additionaly, I have no idea how to fill out bmPlanes and bmPixels.
    Specifies the count of color planes.
    Specifies the number of bits required to indicate the color of a pixel.
    I have no idea where I'd get that information.

    So I wandered off to CreateCompatableBitmap...
    For the CreateCompatableBitmap function, it takes an hdc
    HBITMAP CreateCompatibleBitmap(
      HDC hdc,        // handle to DC
      int nWidth,     // width of bitmap, in pixels
      int nHeight     // height of bitmap, in pixels
    Example to avoid creating a monochrome image:
    HDC memDC = CreateCompatibleDC ( hDC );
    HBITMAP memBM = CreateCompatibleBitmap ( hDC, nWidth, nHeight );
    SelectObject ( memDC, memBM );
    But I'm lost as to what device I'd give the hdc that would also give it the bitmap information (Msdn being vague again -,-). It looks to me like resources might be quicker o_O.

  4. #4
    Registered User
    Join Date
    Oct 2001
    >I was wondering if theres some way to copy the bitmap contents to a constant string, then load it?
    Check out this code by JaWib.
    #include <windows.h>
    #include <iostream>
    class Bitmap
      Bitmap(const char* file)
        m_hImage = (HBITMAP)LoadImage(GetModuleHandle(0),file,IMAGE_BITMAP,0,0,LR_LOADFROMFILE);
      bool operator!() { return m_hImage==0?true:false; }
      void Draw()
        HDC hdc = GetDC(GetConsoleWindow());
        BITMAPINFO bmi = {0};
        bmi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
        if (!GetDIBits(hdc,m_hImage,0,0,0,&bmi,DIB_RGB_COLORS))
          std::cerr<<"Failed to get bitmap info";
        int width = bmi.bmiHeader.biWidth;
        int height = bmi.bmiHeader.biHeight;
        char* bits = new char[width*height*bmi.bmiHeader.biBitCount+sizeof(BITMAPINFOHEADER)];
        memcpy(bits, &bmi.bmiHeader, sizeof(BITMAPINFOHEADER));
        if(!GetDIBits(hdc, m_hImage, 0, height, bits+bmi.bmiHeader.biSize, (LPBITMAPINFO)bits, DIB_RGB_COLORS))
          std::cerr<<"Failed to get bits: "<<GetLastError();
        if (!SetDIBitsToDevice(hdc,0,0,width,height,0,0,0,height,bits+bmi.bmiHeader.biSize,(LPBITMAPINFO)bits,DIB_RGB_COLORS))
          std::cerr<<"Failed to draw"<<GetLastError();
      HBITMAP m_hImage;
    std::ostream& operator<<(std::ostream& os, Bitmap& image)
      return os;
    int main()
      Bitmap image("image.bmp");
        std::cerr<<"Failed to load image";
        return 1;
    It was posted under this thread:
    Last edited by swoopy; 09-02-2006 at 01:26 AM.

  5. #5
    60% Braindead
    Join Date
    Dec 2005
    Wow, thats going to take a minute to figure out haha. In the meantime, I think I'll stick with resources until I can understand what the hell thats doing lol. Thanks tonto & swoopy.

  6. #6
    Registered User
    Join Date
    Oct 2001
    >Wow, thats going to take a minute to figure out haha.
    Same here, I haven't looked at it in detail, but remember thinking when I originally browsed the thread that this is some nifty code.

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