Developer CD Series 1995 February: Tool Chest/Dev.CD Feb 95/Dev.CD Feb 95.toast/Sample Code/Sprocket/Lib/Window.cp

Text File | 1994-12-06 | 22.4 KB | 911 lines | [TEXT/MPS ]

/*
    File:        Window.cp

    Contains:    Implementation of TWindow, a base class which provides a
                framework for building way-cool windows which even John
                Sullivan would be happy with. Floating windows and “smart
                zooming” algorithms are based on code samples provided by
                Dean Yu. Tim Craycroft, the guy making the window manager
                do all this work for you has also been a great help.

    Written by: Dave Falkenburg

    Copyright:    © 1993-94 by Dave Falkenburg, all rights reserved.

    Change History (most recent first):

        <10>     12/6/94    DRF        Rolled in David Den Boer’s fixes. Also add the conditionals for
                                    newest universal headers again.
         <9>    11/23/94    DRF        Bite the bullet just require the latest universal headers
         <8>    11/17/94    DRF        Add casts for CFront & PPCC. Also dealt with the change to
                                    ClipAbove in the latest universal headers.
         <7>    11/12/94    DRF        Added AdjustMenusBeforeMenuSelection.
         <6>     11/8/94    DRF        Add some better menu handling methods.
         <5>     9/27/94    DRF         AppLib.h is now Sprocket.h
         <4>      9/9/94    DRF        Reorganized headers and removed redundant #includes.
         <3>      9/4/94    DRF        Added DrawJustTheGrowIcon.
         <2>     8/27/94    DRF        In TWindow::Close, call window’s (de)Activate method before
                                    closing so that menus can be properly updated.

    To Do:        Make sure invisible windows can be created & managed
                Handle modal windows as another class of windows
                Fix activate bugs when showing and hiding windows
                Window positioning methods (getters and setters)
                Display Manager support
                Changes to support AEObject model
 */

#include "Sprocket.h"
#include "Window.h"

#include <Script.h>        //    for GetMBarHeight()
#include <LowMem.h>        //    for LMGetWindowList()


const short            kFloatingWindowKind        = 1000;
const short            kNormalWindowKind        = 1001;
const WindowPtr     kNoFloatingWindows        = (WindowPtr) -1;

const short            kScreenEdgeSlop            = 4;
const short            kSpaceForFinderIcons    = 64;
const short            kMinimumTitleBarHeight    = 21;
const short            kMinimumWindowSize        = 32;

static void            HiliteShowHideFloatingWindows(Boolean hiliting,Boolean hiding);

static void            FindScreenRectWithLargestPartOfWindow(WindowPtr aWindow,Rect *theBestScreenRect, GDHandle * theBestDevice);
static pascal void    CalculateWindowAreaOnDevice(short depth,short deviceFlags,GDHandle targetDevice,long userData);


struct    CalcWindowAreaDeviceLoopUserData
    {
    GDHandle    fScreenWithLargestPartOfWindow;
    long        fLargestArea;
    Rect        fWindowBounds;
    };





TWindow::TWindow()
    {
    }


TWindow::~TWindow()
    {
    }


void
TWindow::CreateWindow(WindowType typeOfWindowToCreate /* = kNormalWindow */)
    {
    WindowPtr    behindWindow,oldFrontMostWindow;

    if (typeOfWindowToCreate == kModalWindow)
        {
        DebugStr((StringPtr) "\pModal windows aren’t supported yet");
        fWindowType = kFloatingWindow;
        return;
        }
    else if (typeOfWindowToCreate == kFloatingWindow)
        {
        behindWindow = (WindowPtr) -1;
        oldFrontMostWindow = FrontWindow();

        fWindowType = kFloatingWindow;
        }
    else if (typeOfWindowToCreate == kNormalWindow)
        {
        behindWindow = LastFloatingWindow();

        fWindowType = kNormalWindow;

        if (behindWindow == kNoFloatingWindows)
            oldFrontMostWindow = FrontNonFloatingWindow();    // •••
        else
            oldFrontMostWindow = (WindowPtr) ((WindowPeek) behindWindow)->nextWindow;
        }

    fWindow = this->MakeNewWindow(behindWindow);
    fIsVisible = ((WindowPeek) fWindow)->visible;

    if (fWindow)
        {
        SetWRefCon(fWindow,(long) this);

        if (typeOfWindowToCreate == kModalWindow)
            {
            DebugStr((StringPtr) "\pCan’t create Modal windows yet");
            }
        else if (typeOfWindowToCreate == kFloatingWindow)
            {
            ((WindowPeek) fWindow)->windowKind = kFloatingWindowKind;

            //    make sure the other window stays hilited
            if (oldFrontMostWindow)
                HiliteAndActivateWindow(oldFrontMostWindow,true);
            }
        else if (typeOfWindowToCreate == kNormalWindow)
            {
            ((WindowPeek) fWindow)->windowKind = kNormalWindowKind;

            //    unhighlight the old front window
            if (oldFrontMostWindow)
                HiliteAndActivateWindow(oldFrontMostWindow,false);

            //    hilite the new window…
            HiliteAndActivateWindow(fWindow,true);
            }
        }
    }


void
TWindow::AdjustCursor(EventRecord * /* anEvent */)
    {
    }

void
TWindow::Idle(EventRecord * /* anEvent */)
    {
    }

void
TWindow::Activate(Boolean /* activating */)
    {
    }

void
TWindow::Draw(void)
    {
    }

void
TWindow::Click(EventRecord * /* anEvent */)
    {
    }

void
TWindow::KeyDown(EventRecord * /* anEvent */)
    {
    }


void
TWindow::Select(void)
    {
    WindowPtr    currentFrontWindow;

    if (fWindowType == kFloatingWindow)
        currentFrontWindow = FrontWindow();
    else if (fWindowType == kNormalWindow)
        currentFrontWindow = FrontNonFloatingWindow();
    else
        {
        }

    if (currentFrontWindow != fWindow)
        {
        if (fWindowType == kFloatingWindow)
            BringToFront(fWindow);
        else
            {
            WindowPtr    lastFloater = LastFloatingWindow();

            // Deactivate the window currently in front.

            HiliteAndActivateWindow(currentFrontWindow,false);

            if (lastFloater == kNoFloatingWindows)
                {
                //    If there are no floating windows,
                //    just call SelectWindow like the good ol’ days

                SelectWindow(fWindow);
                }
            else
                {
                // Bring it behind the last floating window and activate it.
                // Note that Inside Mac 1 states that you need to call PaintOne() and CalcVis() on a
                // window if you are using SendBehind() to bring it closer to the front.  With System 7,
                // this is no longer necessary.

                SendBehind(fWindow,lastFloater);
                }

            //    Hilite the new front window

            HiliteAndActivateWindow(fWindow,true);
            }
        }
    }


void
TWindow::Drag(Point startPoint)
    {
    GrafPtr        savePort;
    KeyMap        theKeyMap;
    Boolean        commandKeyDown = false;
    RgnHandle    draggingRegion;
    long        dragResult;

    if (WaitMouseUp())        //    de-bounce?
        {
        // Set up the Window Manager port.

        GetPort(&savePort);
        SetPort(gWindowManagerPort);
        SetClip(GetGrayRgn());

        // Check to see if the command key is down.

        GetKeys(theKeyMap);
        commandKeyDown = ((theKeyMap[1] & 0x8000) != 0);

        if (commandKeyDown)
            {
            //    We’re not going to change window ordering,
            //    so make sure that we don’t drag in front of
            //    other windows which may be in front of ours.

#if    qUseNewUniversalInterfaces
            ClipAbove(fWindow);
#else
            ClipAbove((WindowPeek) fWindow);
#endif
            }
        else if (fWindowType != kFloatingWindow)
            {
            //    We’re dragging a normal window, so make sure
            //    that we don’t drag in front of any floating
            //    windows.

#if    qUseNewUniversalInterfaces
            ClipAbove(FrontNonFloatingWindow());
#else
            ClipAbove((WindowPeek) FrontNonFloatingWindow());
#endif
            }

        //    Drag an outline of the window around the desktop.
        //    NOTE: DragGrayRgn destroys the region passed in, so make a copy

        draggingRegion = NewRgn();
        CopyRgn(((WindowPeek)fWindow)->strucRgn,draggingRegion);
        dragResult = DragGrayRgn(draggingRegion, startPoint, &gDeskRectangle, &gDeskRectangle, noConstraint, nil);
        DisposeRgn(draggingRegion);


        SetPort(savePort);    //    Get back to old port

        if ((dragResult != 0) && (dragResult != 0x80008000))
            {
            this->Nudge((short) (dragResult & 0xFFFF),(short) (dragResult >> 16));
            }
        }

    if (!commandKeyDown)
        Select();
    }

void
TWindow::Nudge(short horizontalDistance, short verticalDistance)
    {
    WindowPeek    windowAsWindowPeek = (WindowPeek) fWindow;
    short        newHorizontalPosition,newVerticalPosition;

    newHorizontalPosition = (short) (**windowAsWindowPeek->contRgn).rgnBBox.left + horizontalDistance;
    newVerticalPosition = (short) (**windowAsWindowPeek->contRgn).rgnBBox.top + verticalDistance;

    MoveWindow(fWindow,newHorizontalPosition,newVerticalPosition,false);
    }

void
TWindow::Grow(Point startPoint)
    {
    GrafPtr    oldPort;
    long    newSize;
    Rect    oldWindowRect,resizeLimits;

    GetPort(&oldPort);

    GetWindowSizeLimits(&resizeLimits);
    newSize = GrowWindow(fWindow,startPoint,&resizeLimits);
    if (newSize)
        {
        oldWindowRect = fWindow->portRect;
        SizeWindow(fWindow,(short) newSize,(short) (newSize >> 16),true);
        SetPort(fWindow);
        this->AdjustForNewWindowSize(&oldWindowRect,&fWindow->portRect);
        }

    SetPort(oldPort);
    }


void
TWindow::Zoom(short zoomState)
    {
    GrafPtr        oldPort;
    FontInfo    systemFontInfo;
    short        titleBarHeight;
    Rect        bestScreenRect,perfectWindowRect,scratchRect;
    short        amountOffscreen;
    WindowPeek    windowAsWindowPeek = (WindowPeek) fWindow;
    GDHandle    bestDevice;

    GetPort(&oldPort);

    //    Figure out the height of the title bar so we can properly position
    //    a window. The algorithm is stolen from the System 7.x 'WDEF' (0)
    //
    //    This probably isn’t the best thing to do: A better way might be
    //    to diff the structure and content region rectangles?

    SetPort(gWindowManagerPort);
    GetFontInfo(&systemFontInfo);
    titleBarHeight = (short) (systemFontInfo.ascent + systemFontInfo.descent + 4);
    if ((titleBarHeight % 2) == 1)
        titleBarHeight--;
    if (titleBarHeight < kMinimumTitleBarHeight)
        titleBarHeight = kMinimumTitleBarHeight;


    //    Only do the voodoo magic if we are really “zooming” the window.

    if (zoomState == inZoomOut)
        {
        FindScreenRectWithLargestPartOfWindow(fWindow,&bestScreenRect,&bestDevice);
        bestScreenRect.top += titleBarHeight;

        this->GetPerfectWindowSize(&perfectWindowRect);
        OffsetRect(&perfectWindowRect,-perfectWindowRect.left,-perfectWindowRect.top);

        //    Take the zero-pined perfect window size and move it to
        //    the top left of the    window’s content region.

        OffsetRect(&perfectWindowRect,(**windowAsWindowPeek->contRgn).rgnBBox.left,
                                      (**windowAsWindowPeek->contRgn).rgnBBox.top);


        //    Does perfectWindowRect fit completely on the best screen?

        SectRect(&perfectWindowRect, &bestScreenRect, &scratchRect);
        if (!EqualRect(&perfectWindowRect, &scratchRect))
            {
            //    SectRect sez perfectWindowRect doesn’t completely fit
            //    on the screen, so bump the window so that more of it fits.

            //    Make sure that the left edge of perfectWindowRect is forced
            //    onto the best screen.  This is in case we are bumping
            //    the window to the right.

            amountOffscreen = bestScreenRect.left - perfectWindowRect.left;
            if (amountOffscreen > 0)
                {
                perfectWindowRect.left += amountOffscreen;
                perfectWindowRect.right += amountOffscreen;
                }

            //    Make sure that the left edge of perfectWindowRect is forced
            //    onto the best screen.  This is in case we are bumping
            //    the window downward to a new screen.

            amountOffscreen = bestScreenRect.top - perfectWindowRect.top;
            if (amountOffscreen > 0)
                {
                perfectWindowRect.top += amountOffscreen;
                perfectWindowRect.bottom += amountOffscreen;
                }

            //    If right edge of window falls off the screen,
            //        Move window to the left until the right edge IS on the screen
            //        OR the left edge is at bestScreenRect.left

            amountOffscreen = perfectWindowRect.right - bestScreenRect.right;
            if (amountOffscreen > 0)
                {
                //    Are we going to push the left edge offscreen? If so, change the
                //    offset so we move the window all the way over to the left.

                if ((perfectWindowRect.left - amountOffscreen) < bestScreenRect.left)
                    amountOffscreen = perfectWindowRect.left - bestScreenRect.left;

                perfectWindowRect.left -= amountOffscreen;
                perfectWindowRect.right -= amountOffscreen;
                }

            //    If bottom edge of window falls off the screen,
            //        Move window to up until the bottom edge IS on the screen
            //        OR the top edge is at bestScreenRect.top

            amountOffscreen = perfectWindowRect.bottom - bestScreenRect.bottom;
            if (amountOffscreen > 0)
                {
                //    Are we going to push the top edge offscreen? If so, change the
                //    offset so we move the window just to the top.

                if ((perfectWindowRect.top - amountOffscreen) < bestScreenRect.top)
                    amountOffscreen = perfectWindowRect.top - bestScreenRect.top;

                perfectWindowRect.top -= amountOffscreen;
                perfectWindowRect.bottom -= amountOffscreen;
                }

            SectRect(&perfectWindowRect, &bestScreenRect, &scratchRect);
            if (!EqualRect(&perfectWindowRect, &scratchRect))
                {
                //    The edges of the window still fall offscreen,
                //    so make the window smaller until it fits.

                if (perfectWindowRect.bottom > bestScreenRect.bottom)
                    perfectWindowRect.bottom = bestScreenRect.bottom;

                //    If the right edge is still falling off,
                //        save space for Finder’s disk icons as well.

                if (perfectWindowRect.right > bestScreenRect.right)
                    {
                    perfectWindowRect.right = bestScreenRect.right;

                    //    If we were on the main screen, leave room for Finder icons, too.

                    if (bestDevice == GetMainDevice())
                        perfectWindowRect.right -= kSpaceForFinderIcons;
                    }
                }
            }

        //    Stash our new rectangle inside of the Window’s dataHandle
        //    so that ZoomWindow does the right thing.

        (**((WStateDataHandle) (windowAsWindowPeek->dataHandle))).stdState = perfectWindowRect;
        }

    //    HEY YOU! Don’t forget to set the port to the window being zoomed
    //    Why, you ask? Because IM-IV-50 says to; otherwise you die

    SetPort(fWindow);

    Rect    oldWindowRect = fWindow->portRect;

    ZoomWindow(fWindow,zoomState,false);
    this->AdjustForNewWindowSize(&oldWindowRect,&fWindow->portRect);

    SetPort(oldPort);
    }

void
TWindow::ShowHide(Boolean showFlag)
    {
    //    Here we need the “::” in front of ShowHide to indicate we are calling
    //    the global function, and not the method ShowHide. Unintended recursion
    //    can do bad things to the unsuspecting programmer.

    //    Some C++ programmers would always prepend the “::” on function calls.

    ::ShowHide(fWindow,showFlag);
    fIsVisible = showFlag;
    }


Boolean
TWindow::EventFilter(EventRecord * /* theEvent */)
    {
    return false;
    }


void
TWindow::GetPerfectWindowSize(Rect *perfectSize)
    {
    *perfectSize = qd.screenBits.bounds;
    }

void
TWindow::GetWindowSizeLimits(Rect *limits)
    {
    limits->top = limits->left = kMinimumWindowSize;
    limits->right = gDeskRectangle.right - gDeskRectangle.left;
    limits->bottom = gDeskRectangle.bottom - gDeskRectangle.top;
    }

void
TWindow::AdjustForNewWindowSize(Rect * /* oldRect */, Rect * /* newSize */)
    {
    }


Boolean
TWindow::IsVisible(void)
    {
    return fIsVisible;
    }


Boolean
TWindow::CanClose(void)
    {
    return true;
    }


Boolean
TWindow::Close(void)
    {
    WindowPtr    newFrontWindow = nil;

    if (FrontNonFloatingWindow() == fWindow)
        newFrontWindow = (WindowPtr) ((WindowPeek) fWindow)->nextWindow;

    this->Activate(false);
    DisposeWindow(fWindow);

    if (newFrontWindow)
        HiliteAndActivateWindow(newFrontWindow,true);

    return true;
    }


Boolean
TWindow::DeleteAfterClose(void)
    {
    return true;
    }


void
TWindow::AdjustMenusBeforeMenuSelection(void)
    {
    }


void
TWindow::DoMenuSelection(short /* menu */, short /* item */)
    {
    }


void
TWindow::DoMenuCommand(unsigned long /* menuCommand */)
    {
    }


OSErr
TWindow::HandleDrag(DragTrackingMessage dragMessage,DragReference theDrag)
    {
    OSErr    result = dragNotAcceptedErr;

    switch (dragMessage)
        {
        case    dragTrackingEnterWindow:
            result = this->DragEnterWindow(theDrag);
            break;

        case    dragTrackingInWindow:
            result = this->DragInWindow(theDrag);
            break;

        case    dragTrackingLeaveWindow:
            result = this->DragLeaveWindow(theDrag);
            break;

        default:
            break;
        }

    return result;
    }


OSErr
TWindow::DragEnterWindow(DragReference /* theDrag */)
    {
    return dragNotAcceptedErr;
    }


OSErr
TWindow::DragInWindow(DragReference /* theDrag */)
    {
    return dragNotAcceptedErr;
    }


OSErr
TWindow::DragLeaveWindow(DragReference /* theDrag */)
    {
    return dragNotAcceptedErr;
    }


OSErr
TWindow::HandleDrop(DragReference /* theDrag */)
    {
    return dragNotAcceptedErr;
    }


///////////////////////////////////////////////////////////////////////////
//
//    Utility Functions used for floating windows
//

TWindow *
GetWindowObject(WindowPtr aWindow)
    {
    short    wKind;

    if (aWindow != nil)
        {
        wKind = ((WindowPeek) aWindow)->windowKind;

        if (wKind >= userKind)
            {
            //    All windowKinds >= userKind are based upon TWindow

            return (TWindow *) GetWRefCon(aWindow);
            }
        }
    return (TWindow *) nil;
    }


////////////////////////////////////////////////////////////////////////
//
//    Utility functions


pascal WindowPtr
GetNewColorOrBlackAndWhiteWindow(short windowID, void *wStorage, WindowPtr behind)
    {
    if (gHasColorQuickdraw)
        return GetNewCWindow(windowID,wStorage,behind);
    else
        return GetNewWindow(windowID,wStorage,behind);
    }


pascal WindowPtr
NewColorOrBlackAndWhiteWindow(void *wStorage, const Rect *boundsRect, ConstStr255Param title, Boolean visible, short theProc, WindowPtr behind, Boolean goAwayFlag, long refCon)
    {
    if (gHasColorQuickdraw)
        return NewCWindow(wStorage,boundsRect,title,visible,theProc,behind,goAwayFlag,refCon);
    else
        return NewWindow(wStorage,boundsRect,title,visible,theProc,behind,goAwayFlag,refCon);
    }


void
DrawJustTheGrowIcon(WindowPtr aWindow)
    {
    GrafPtr        savedPort;
    RgnHandle    savedClip = NewRgn();
    Rect        growBoxRect;

    GetPort(&savedPort);
    SetPort(aWindow);
    GetClip(savedClip);

    //    clip to just the bottom right corner of the window

    growBoxRect.top = aWindow->portRect.bottom - kScrollbarWidth;
    growBoxRect.bottom = aWindow->portRect.bottom;
    growBoxRect.left = aWindow->portRect.right - kScrollbarWidth;
    growBoxRect.right = aWindow->portRect.right;
    ClipRect(&growBoxRect);

    DrawGrowIcon(aWindow);

    SetClip(savedClip);
    DisposeRgn(savedClip);

    SetPort(savedPort);
    }


WindowPtr
LastFloatingWindow(void)
    {
    WindowPeek    aWindow = (WindowPeek) FrontWindow();
    WindowPtr    lastFloater = (WindowPtr) kNoFloatingWindows;

    while (aWindow && (aWindow->windowKind == kFloatingWindowKind))
        {
        if (aWindow->visible)
            lastFloater = (WindowPtr) aWindow;

        aWindow = (WindowPeek) aWindow->nextWindow;
        }
    return(lastFloater);
    }


WindowPtr
FrontNonFloatingWindow(void)
    {
    WindowPeek    aWindow = (WindowPeek) LMGetWindowList();

    //    Skip over floating windows

    while (aWindow && (aWindow->windowKind == kFloatingWindowKind))
        aWindow = (WindowPeek) aWindow->nextWindow;

    //    Skip over invisible, but otherwise normal windows

    while (aWindow && (aWindow->visible == 0))
        aWindow = (WindowPeek) aWindow->nextWindow;

    return (WindowPtr) aWindow;
    }


void
HiliteAndActivateWindow(WindowPtr aWindow,Boolean active)
    {
    GrafPtr        oldPort;
    TWindow    *    wobj = GetWindowObject(aWindow);

    if (aWindow)
        {
        HiliteWindow(aWindow,active);

        if (wobj != nil)
            {
            GetPort(&oldPort);
            SetPort(aWindow);
            wobj->Activate(active);
            SetPort(oldPort);
            }
        }
    }

void
SuspendResumeWindows(Boolean resuming)
    {
    //    When we suspend/resume, hide/show all the visible floaters

    HiliteShowHideFloatingWindows(resuming,true);
    }

void
HiliteWindowsForModalDialog(Boolean hiliting)
    {
    //    When we display a modal dialog, we need to unhighlight
    //    all visible floaters. We also need to re-hilite them
    //    afterwards.

    HiliteShowHideFloatingWindows(hiliting,false);
    }

void
HiliteShowHideFloatingWindows(Boolean hiliting,Boolean dohiding)
    {
    WindowPeek    aWindow;
    TWindow *    wobj;

    HiliteAndActivateWindow(FrontNonFloatingWindow(),hiliting);

    aWindow = (WindowPeek) LMGetWindowList();
    while (aWindow && aWindow->windowKind == kFloatingWindowKind)
        {
        wobj = GetWindowObject((WindowPtr) aWindow);

        //    If we are hiding or showing, only hide/show windows
        //    that were visible to begin with.

        //    NOTE:    We use our copy of the visible flag so we can
        //            automatically show floaters on a resume event.

        //    NOTE:    Since this isn’t a method of TWindow, we don’t
        //            really need the “::” on ShowHide, but as long
        //            as we’re trying to avoid ambiguity.

        if (dohiding && (wobj != nil) && (wobj->IsVisible()))
            ::ShowHide((WindowPtr) aWindow,hiliting);

        //    All floaters are hilited if any floater is hilited

        HiliteWindow((WindowPtr) aWindow,hiliting);
        aWindow = (WindowPeek) aWindow->nextWindow;
        }
    }


///////////////////////////////////////////////////////////////////////////
//
//    Routines used for dealing with windows and multiple screens
//

pascal void
CalculateWindowAreaOnDevice(short /* depth */,short /* deviceFlags */,GDHandle targetDevice,long userData)
    {
    CalcWindowAreaDeviceLoopUserData *    deviceLoopDataPtr;
    long                                windowAreaOnThisScreen;
    Rect                                windowRectOnThisScreen;

    deviceLoopDataPtr = (CalcWindowAreaDeviceLoopUserData *) userData;

    SectRect(&deviceLoopDataPtr->fWindowBounds, &(**targetDevice).gdRect,&windowRectOnThisScreen);
    OffsetRect(&windowRectOnThisScreen,-windowRectOnThisScreen.left,-windowRectOnThisScreen.top);
    windowAreaOnThisScreen = windowRectOnThisScreen.right * windowRectOnThisScreen.bottom;

    if (windowAreaOnThisScreen > deviceLoopDataPtr->fLargestArea)
        {
        deviceLoopDataPtr->fLargestArea = windowAreaOnThisScreen;
        deviceLoopDataPtr->fScreenWithLargestPartOfWindow = targetDevice;
        }
    }


DeviceLoopDrawingUPP CallCalcWindowAreaOnDevice = NewDeviceLoopDrawingProc(&CalculateWindowAreaOnDevice);


void
FindScreenRectWithLargestPartOfWindow(WindowPtr aWindow,Rect *theBestScreenRect,GDHandle * theBestDevice)
    {
    RgnHandle                            copyOfWindowStrucRgn;
    CalcWindowAreaDeviceLoopUserData    deviceLoopData;

    //    Use DeviceLoop to find out what GDevice contains the largest
    //    portion of the supplied window.
    //
    //    NOTE:    Assumes thePort == the Window Manager Port because we using
    //            the window strucRgn, not contRgn.

    deviceLoopData.fScreenWithLargestPartOfWindow = nil;
    deviceLoopData.fLargestArea = -1;
    deviceLoopData.fWindowBounds = (**(((WindowPeek) aWindow)->contRgn)).rgnBBox;

    copyOfWindowStrucRgn = NewRgn();
    CopyRgn(((WindowPeek) aWindow)->strucRgn,copyOfWindowStrucRgn);

    DeviceLoop(copyOfWindowStrucRgn,CallCalcWindowAreaOnDevice,(long) &deviceLoopData,singleDevices);

    DisposeRgn(copyOfWindowStrucRgn);

    *theBestDevice = deviceLoopData.fScreenWithLargestPartOfWindow;
    *theBestScreenRect = (**(deviceLoopData.fScreenWithLargestPartOfWindow)).gdRect;

    //    Leave some space around the edges of the screen so window look good, AND
    //    if the best device is the main screen, leave space for the Menubar

    InsetRect(theBestScreenRect,kScreenEdgeSlop,kScreenEdgeSlop);
    if (GetMainDevice() == deviceLoopData.fScreenWithLargestPartOfWindow)
        theBestScreenRect->top += GetMBarHeight();
    }


///////////////////////////////////////////////////////////////////////////
//
//    Drag Manager callback routines which dispatch to a window’s method
//

pascal OSErr
CallWindowDragTrackingHandler(DragTrackingMessage dragMessage,WindowPtr theWindow,void * /* refCon */,DragReference theDrag)
    {
    TWindow *wobj = GetWindowObject(theWindow);

    if (wobj)
        return(wobj->HandleDrag(dragMessage,theDrag));
    else
        return dragNotAcceptedErr;
    }


pascal OSErr
CallWindowDragReceiveHandler(WindowPtr theWindow,void * /* refCon */,DragReference theDrag)
    {
    TWindow *wobj = GetWindowObject(theWindow);

    if (wobj)
        return(wobj->HandleDrop(theDrag));
    else
        return dragNotAcceptedErr;
    }