Comments

• RE: 'Other methods' listed in comments

  Posted by Legacy on 03/11/1999 12:00am

  Originally posted by: Paul Reynolds

  CImageList method:

  The CImageList method is rather fixed requiring you to have a predefined bitmap....and is nothing to do with the method actually listed....If you really want to draw an image easily using a predefined image, you would use an Icon anyway...

  Another Method:

  If this is another method to that which has already be described, why not submit it separately?!
  

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• Transparent Bitmap

  Posted by Legacy on 03/09/1999 12:00am

  Originally posted by: wubin huzheng

  There's a simple method to draw a transparent bitmap by calling class
  
  CImageList.
  
  
  
  CBitmap bitmapImage;	
  
  //load bitmap from resource
  
  bitmapImage.LoadBitmap(IDB_BITMAP);  
  
     
  
  BITMAP bmpInfo;	
  
  CSize bitSize;
  
  //get size of bitmap
  
  bitmapImage.GetBitmap(&bmpInfo);	
  
  bitSize = CSize(bmpInfo.bmWidth, bmpInfo.bmHeight);
  
  CDC* pwholeWndDC;
  
  pwholeWndDC=GetDC();
  
  CImageList imageList;	
  
  //create ImageList
  
  imageList.Create(bitSize.cx, bitSize.cy, ILC_COLOR|ILC_MASK, 1, 1);
  
  //select color white is transparent color
  
  imageList.Add(&bitmapImage, RGB(0,0,0));	      
  
  CPoint ptLocation(0,0);	
  
  //drawing the first bitmap of imagelist Transparently
  
  bitmapImage.Draw(pwholeWndDC, 0, ptLocation, ILD_TRANSPARENT);	
  
  
  

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• Another Method

  Posted by Legacy on 01/23/1999 12:00am

  Originally posted by: Shaun Cooley

  Here is another method, the advantage to this message 
  
  is that the bitmap is only drawn on the visible DC once.
  
  This reduces flicker on slower systems.
  
  // This is by Jeff Prosise:
  
  void CMaskedBitmap::DrawTransparent (CDC* pDC, int x, int y, COLORREF crColor)
  
  {
  
  	BITMAP bm;
  
  	GetObject (sizeof (BITMAP), &bm);
  
  	CPoint size (bm.bmWidth, bm.bmHeight);
  
  	pDC->DPtoLP (&size);
  
      CPoint org (0, 0);
  
  	pDC->DPtoLP (&org);
  
      // Create a memory DC (dcImage) and select the bitmap into it
  
  	CDC dcImage;
  
  	dcImage.CreateCompatibleDC (pDC);
  
  	CBitmap* pOldBitmapImage = dcImage.SelectObject (this);
  
  	dcImage.SetMapMode (pDC->GetMapMode ());
  
      // Create a second memory DC (dcAnd) and in it create an AND mask
  
  	CDC dcAnd;
  
  	dcAnd.CreateCompatibleDC (pDC);
  
  	dcAnd.SetMapMode (pDC->GetMapMode ());
  
      CBitmap bitmapAnd;
  
  	bitmapAnd.CreateBitmap (bm.bmWidth, bm.bmHeight, 1, 1, NULL);
  
  	CBitmap* pOldBitmapAnd = dcAnd.SelectObject (&bitmapAnd);
  
      dcImage.SetBkColor (crColor);
  
  	dcAnd.BitBlt (org.x, org.y, size.x, size.y, &dcImage, org.x, org.y,
  
  	    SRCCOPY);
  
      // Create a third memory DC (dcXor) and in it create an XOR mask
  
  	CDC dcXor;
  
  	dcXor.CreateCompatibleDC (pDC);
  
  	dcXor.SetMapMode (pDC->GetMapMode ());
  
      CBitmap bitmapXor;
  
  	bitmapXor.CreateCompatibleBitmap (&dcImage, bm.bmWidth, bm.bmHeight);
  
  	CBitmap* pOldBitmapXor = dcXor.SelectObject (&bitmapXor);
  
      dcXor.BitBlt (org.x, org.y, size.x, size.y, &dcImage, org.x, org.y, SRCCOPY);
  
      dcXor.BitBlt (org.x, org.y, size.x, size.y, &dcAnd, org.x, org.y, 0x220326);
  
      // Copy the pixels in the destination rectangle to a temporary
  
  	// memory DC (dcTemp)
  
  	CDC dcTemp;
  
  	dcTemp.CreateCompatibleDC (pDC);
  
  	dcTemp.SetMapMode (pDC->GetMapMode ());
  
      CBitmap bitmapTemp;
  
  	bitmapTemp.CreateCompatibleBitmap (&dcImage, bm.bmWidth, bm.bmHeight);
  
  	CBitmap* pOldBitmapTemp = dcTemp.SelectObject (&bitmapTemp);
  
      dcTemp.BitBlt (org.x, org.y, size.x, size.y, pDC, x, y, SRCCOPY);
  
      // Generate the final image by applying the AND and XOR masks to
  
  	// the image in the temporary memory DC
  
  	dcTemp.BitBlt (org.x, org.y, size.x, size.y, &dcAnd, org.x, org.y, SRCAND);
  
      dcTemp.BitBlt (org.x, org.y, size.x, size.y, &dcXor, org.x, org.y, SRCINVERT);
  
      // Blit the resulting image to the screen
  
  	pDC->BitBlt (x, y, size.x, size.y, &dcTemp, org.x, org.y, SRCCOPY);
  
      // Restore the default bitmaps
  
  	dcTemp.SelectObject (pOldBitmapTemp);
  
  	dcXor.SelectObject (pOldBitmapXor);
  
  	dcAnd.SelectObject (pOldBitmapAnd);
  
  	dcImage.SelectObject (pOldBitmapImage);
  
  }
  
  
  

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