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how speed up DIB's and Regions?

Cambalinho (1445)
i have these code for DIB's:
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BYTE* Get24BitPixels(HBITMAP pBitmap, WORD *pwWidth, WORD *pwHeight)
    {
        // a bitmap object just to get bitmap width and height
        BITMAP bmpBmp;

        // pointer to original bitmap info
        LPBITMAPINFO pbmiInfo;

        // bitmap info will hold the new 24bit bitmap info
        BITMAPINFO bmiInfo;

        // width and height of the bitmap
        WORD wBmpWidth, wBmpHeight;

        // ---------------------------------------------------------
        // get some info from the bitmap
        // ---------------------------------------------------------
        GetObject(pBitmap, sizeof(bmpBmp),&bmpBmp);
        pbmiInfo   = (LPBITMAPINFO)&bmpBmp;

        // get width and height
        wBmpWidth  = (WORD)pbmiInfo->bmiHeader.biWidth;
        wBmpWidth -= (wBmpWidth%4);                       // width is 4 byte boundary aligned.
        wBmpHeight = (WORD)pbmiInfo->bmiHeader.biHeight;

        // copy to caller width and height parms
        *pwWidth  = wBmpWidth;
        *pwHeight = wBmpHeight;
        // ---------------------------------------------------------

        // allocate width * height * 24bits pixels
        //BYTE *pPixels = new BYTE[wBmpWidth*wBmpHeight*3];
        BYTE *pPixels = new (std::nothrow) BYTE[wBmpWidth*wBmpHeight*3];
        if (pPixels==0)
            return NULL;

        // get user desktop device context to get pixels from
        HDC hDC = GetWindowDC(NULL);

        // fill desired structure
        bmiInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
        bmiInfo.bmiHeader.biWidth = wBmpWidth;
        bmiInfo.bmiHeader.biHeight = -wBmpHeight;
        bmiInfo.bmiHeader.biPlanes = 1;
        bmiInfo.bmiHeader.biBitCount = 24;
        bmiInfo.bmiHeader.biCompression = BI_RGB;
        bmiInfo.bmiHeader.biSizeImage = wBmpWidth*wBmpHeight*3;
        bmiInfo.bmiHeader.biXPelsPerMeter = 0;
        bmiInfo.bmiHeader.biYPelsPerMeter = 0;
        bmiInfo.bmiHeader.biClrUsed = 0;
        bmiInfo.bmiHeader.biClrImportant = 0;

        // get pixels from the original bitmap converted to 24bits
        int iRes = GetDIBits(hDC,pBitmap,0,wBmpHeight,(LPVOID)pPixels,&bmiInfo,DIB_RGB_COLORS);

        // release the device context
        ReleaseDC(NULL,hDC);

        // if failed, cancel the operation.
        if (!iRes)
        {
            delete[] pPixels;
            return NULL;
        };

        // return the pixel array
        return pPixels;
    }

and Regions:
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HRGN RegionbyBitmap(HBITMAP pBitmap,COLORREF clrTransparent=-1 )
    {
        BYTE jTranspR = GetRValue(clrTransparent), jTranspG=GetGValue(clrTransparent), jTranspB=GetBValue(clrTransparent);
        // bitmap width and height
        WORD wBmpWidth,wBmpHeight;

        // the final region and a temporary region
        HRGN hRgn, hTmpRgn;

        // 24bit pixels from the bitmap
        BYTE *pPixels = Get24BitPixels(pBitmap, &wBmpWidth, &wBmpHeight);
        if (!pPixels) return NULL;

        // create our working region
        hRgn = CreateRectRgn(0,0,wBmpWidth,wBmpHeight);
        if (!hRgn)
        {
            delete[] pPixels;
            return NULL;
        }

        // ---------------------------------------------------------
        // scan the bitmap
        // ---------------------------------------------------------


        DWORD p=0;
        for (WORD y=0; y<wBmpHeight; y++)
        {
            for (WORD x=0; x<wBmpWidth; x++)
            {
              BYTE jRed   = pPixels[p+2];
              BYTE jGreen = pPixels[p+1];
              BYTE jBlue  = pPixels[p+0];

              if ((jRed == jTranspR && jGreen == jTranspG && jBlue == jTranspB))
              {
                // remove transparent color from region
                hTmpRgn = CreateRectRgn(x,y,x+1,y+1);
                CombineRgn(hRgn, hRgn, hTmpRgn, RGN_XOR);
                DeleteObject(hTmpRgn);


              }

              // next pixel
              p+=3;
            }
        }

        // release pixels
        delete[] pPixels;

        return hRgn;
    }

on DIB's: i don't know if theres another way for be more faster;
on Regions: using region on pixel way it can be very slow. can anyone advice me?
(using these code on a timer, it can freezes the application :( )
Last edited on
coder777 (8444)
The best would be using your own bitmap using CreateDIBSection(...):

https://msdn.microsoft.com/en-us/library/windows/desktop/dd183494%28v=vs.85%29.aspx

This allows you to access the pixel directly. You might create it within the WM_SIZE message.

Within the WM_PAINT message:

First create your own dc using CreateCompatibleDC(...):

https://msdn.microsoft.com/en-us/library/windows/desktop/dd183489%28v=vs.85%29.aspx

Select the the previously created bitmap. After you're done with your drawing you need BitBlt(...):

https://msdn.microsoft.com/en-us/library/windows/desktop/dd183370%28v=vs.85%29.aspx

So it becomes visible.

Why do you think you need that region stuff?
Yes, it is slow especially when use with each and every pixel.

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