Transparent 之 TransparentBlt

• TransparentBlt函数

  BOOL TransparentBlt(
    HDC hdcDest,        // handle to destination DC
    int nXOriginDest,   // x-coord of destination upper-left corner
    int nYOriginDest,   // y-coord of destination upper-left corner
    int nWidthDest,     // width of destination rectangle
    int hHeightDest,    // height of destination rectangle
    HDC hdcSrc,         // handle to source DC
    int nXOriginSrc,    // x-coord of source upper-left corner
    int nYOriginSrc,    // y-coord of source upper-left corner
    int nWidthSrc,      // width of source rectangle
    int nHeightSrc,     // height of source rectangle
    UINT crTransparent  // color to make transparent
  

• 示例

  static HBITMAP hBmp;
  static int cxBmp;
  static int cyBmp;
  
       case WM_CREATE:
  		{
  			//load bmp and get bmp info
  			hBmp = LoadBitmap(GetModuleHandle(NULL),MAKEINTRESOURCE(IDB_BALL));
  			BITMAP bmpInfo;
  			GetObject(hBmp,sizeof(BITMAP),&bmpInfo);
  			cxBmp = bmpInfo.bmWidth;
  			cyBmp = bmpInfo.bmHeight;
  			//put window int the middle screen
  			int cxScr = GetSystemMetrics(SM_CXSCREEN);
  			int cyScr = GetSystemMetrics(SM_CYSCREEN);
  			int cxWnd = 400;
  			int cyWnd = 400;
  			MoveWindow(hWnd,(cxScr-cxWnd)/2,(cyScr-cyWnd)/2,cxWnd,cyWnd,TRUE);
  		}
  		break;
  
  	case WM_PAINT:
  		hdc = BeginPaint(hWnd, &ps);
  		{
  			//bg color
  			RECT rcWnd;
  			HBRUSH hBrush;
  			GetClientRect(hWnd,&rcWnd);
  			hBrush = CreateSolidBrush(RGB(0,128,128));
  			FillRect(hdc,&rcWnd,hBrush);
  			DeleteObject(hBrush);
  			//disp bmp
  			HDC hMemDC = CreateCompatibleDC(hdc);
  			HBITMAP hOldBmp = (HBITMAP)SelectObject(hMemDC,hBmp);
  			//BitBlt(hdc,73,58,cxBmp,cyBmp,hMemDC,0,0,SRCCOPY);
  			TransparentBlt(hdc,73,58,cxBmp,cyBmp,hMemDC,0,0,cxBmp,cyBmp,RGB(255,255,255));
  			SelectObject(hMemDC,hOldBmp);
  			DeleteDC(hMemDC);
  
  		}
  		EndPaint(hWnd, &ps);
  		break;
  

• 结果
• BitBlt:

• 
• TransparentBlt:
•