Black Box 4/BlackBox.cdr/progc/c_all592.arj/TI869.ASC

Text File | 1992-04-14 | 5KB | 199 lines

  PRODUCT  :  Borland C++                            NUMBER  :  869
  VERSION  :  All
       OS  :  WIN
     DATE  :  April 14, 1992                           PAGE  :  1/3

    TITLE  :  How To Center A Dialog Box On Its Parent Window




  It is often necessary to center a dialog box on top of its parent
  window for aesthetic reasons.  Who would one do this?  Simple,
  use the function provided below when the dialog box that needs
  centering receives a WM_INITDIALOG message.

  Below is a sample dialog box procedure that shows the use of the
  function UICenterDialog as well as the source for UICenterDialog
  itself.

  Note:  If the dialog box would not be 100% visible by centering
  it on top of its parent window, this code then centers it on the
  Windows desktop.  If this behavior is not necessary simply remove
  the last if statement.

  // CNTRDLG.C
  // Copyright (C) 1992 Borland Internationa, Inc.
  // All Rights Reserved

  // Function to show the use of UICenterDialog
  //...............................................................

  BOOL FAR PASCAL MyDialogProc(HWND hDlg, WORD msg, WORD wParam,
       LONG lParam)
  {
       switch(msg)
       {
            case WM_INITDIALOG:
                 UICenterDialog(hDlg);
                 break;

            default:
                 return TRUE;
       }
       return FALSE;
  }

  // Source for the UICenterDialog function
  //...............................................................

  void UICenterDialog(HWND hDlg)
  {
       int       cxWin,         // Delta X for parent window
                 cyWin,         // Delta Y for parent window













  PRODUCT  :  Borland C++                            NUMBER  :  869
  VERSION  :  All
       OS  :  WIN
     DATE  :  April 14, 1992                           PAGE  :  2/3

    TITLE  :  How To Center A Dialog Box On Its Parent Window




                 xDlg,          // New X coordinate for dialog box
                 yDlg,          // New Y coordinate for dialog box
                 cxDlg,         // Delta X for dialog box
                 cyDlg,         // Delta Y for dialog box
                 cxScreen,      // Delta X for screen
                 cyScreen;      // Delta Y for screen
       RECT      rcDlg,         // Rectangle for dialog box
                 rcPrnt;        // Rectangle for parent window
       HWND      hWndParent;    // Handle the parent window

       // Determine the width and height of the screen.
       cxScreen = GetSystemMetrics(SM_CXSCREEN);
       cyScreen = GetSystemMetrics(SM_CYSCREEN);

       // Determine rectangle for parent window of dialog box.
       hWndParent = GetWindowWord(hDlg, GWW_HWNDPARENT);
       if(IsWindow(hWndParent))
       {
            // Use parent coordinates (rect) to determine where the
            // dialog needs to be on the Windows desktop
            GetWindowRect(hWndParent, &rcPrnt);
            cxWin = rcPrnt.right - rcPrnt.left;
            cyWin = rcPrnt.bottom - rcPrnt.top;
       }
       else
       {
            // We were unable to determine who the parent is,
            // therefore centering the dialog is pointless!  Place
            // it in the upper left corner of the Windows desktop.
            cxWin = 0;     // Force the centering calculation to
            cyWin = 0;     // think that the dialog is centered on
                           // the Windows desktop
       }

       // Determine rectangle for dialog box itself.
       GetWindowRect(hDlg, &rcDlg);
       cxDlg = rcDlg.right - rcDlg.left;
       cyDlg = rcDlg.bottom - rcDlg.top;

       // Determine new dialog X and Y coordinate
       xDlg = (cxWin - cxDlg) / 2;
       xDlg += rcPrnt.left;
       yDlg = (cyWin - cyDlg) / 2;













  PRODUCT  :  Borland C++                            NUMBER  :  869
  VERSION  :  All
       OS  :  WIN
     DATE  :  April 14, 1992                           PAGE  :  3/3

    TITLE  :  How To Center A Dialog Box On Its Parent Window




       yDlg += rcPrnt.top;

       // Center the dialog using new coordinates
       if ((xDlg < 0) || (yDlg < 0) || (xDlg+cxDlg > cxScreen) ||
            (yDlg+cyDlg > cyScreen))
       {
            // If by centering the dialog on top of its parent it
            // would not be 100% visible, then center it on the
            // Windows desktop instead.
            xDlg = (cxScreen - cxDlg) / 2;
            yDlg = (cyScreen - cyDlg) / 2;
       }

       // Move the dialog box to its new home on the desktop
       MoveWindow(hDlg, xDlg, yDlg, cxDlg, cyDlg, TRUE);
  }