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Create bitmap from pixels

5.00/5 (7 votes)
25 Jan 2011CPOL 44.2K  
Create a bitmap from an array of pixels
C++
static HBITMAP Create8bppBitmap(HDC hdc, int width, int height, LPVOID pBits = NULL)
{
    BITMAPINFO *bmi = (BITMAPINFO *)malloc(sizeof(BITMAPINFOHEADER) + sizeof(RGBQUAD) * 256);
    BITMAPINFOHEADER &bih(bmi->bmiHeader);
    bih.biSize = sizeof (BITMAPINFOHEADER);
    bih.biWidth         = width;
    bih.biHeight        = -height;
    bih.biPlanes        = 1;
    bih.biBitCount      = 8;
    bih.biCompression   = BI_RGB;
    bih.biSizeImage     = 0;
    bih.biXPelsPerMeter = 14173;
    bih.biYPelsPerMeter = 14173;
    bih.biClrUsed       = 0;
    bih.biClrImportant  = 0;
    for (int I = 0; I <= 255; I++)
    {
        bmi->bmiColors[I].rgbBlue = bmi->bmiColors[I].rgbGreen = bmi->bmiColors[I].rgbRed = (BYTE)I;
        bmi->bmiColors[I].rgbReserved = 0;
    }

    void *Pixels = NULL;
    HBITMAP hbmp = CreateDIBSection(hdc, bmi, DIB_RGB_COLORS, &Pixels, NULL, 0);

    if(pBits != NULL)
    {
        //fill the bitmap
        BYTE* pbBits = (BYTE*)pBits;
        BYTE *Pix = (BYTE *)Pixels;
        memcpy(Pix, pbBits, width * height);
    }

    free(bmi);

    return hbmp;
}

static HBITMAP CreateBitmapFromPixels( HDC hDC, UINT uWidth, UINT uHeight, UINT uBitsPerPixel, LPVOID pBits)
    {
           if(uBitsPerPixel < 8) // NOT IMPLEMENTED YET
              return NULL;

          if(uBitsPerPixel == 8)
              return Create8bppBitmap(hDC, uWidth, uHeight, pBits);

          HBITMAP hBitmap = 0;
          if ( !uWidth || !uHeight || !uBitsPerPixel )
             return hBitmap;
          LONG lBmpSize = uWidth * uHeight * (uBitsPerPixel/8) ;
          BITMAPINFO bmpInfo = { 0 };
          bmpInfo.bmiHeader.biBitCount = uBitsPerPixel;
          bmpInfo.bmiHeader.biHeight = uHeight;
          bmpInfo.bmiHeader.biWidth = uWidth;
          bmpInfo.bmiHeader.biPlanes = 1;
          bmpInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
               // Pointer to access the pixels of bitmap
          UINT * pPixels = 0;
          hBitmap = CreateDIBSection( hDC, (BITMAPINFO *)&
                                      bmpInfo, DIB_RGB_COLORS, (void **)&
                                      pPixels , NULL, 0);

          if ( !hBitmap )
              return hBitmap; // return if invalid bitmaps

          //SetBitmapBits( hBitmap, lBmpSize, pBits);
          // Directly Write
          memcpy(pPixels, pBits, lBmpSize );

          return hBitmap;
    }

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)