Developer CD Series 1998 August: Tool Chest/Dev.CD Aug 98 TC.toast/Sample Code/QuickDraw/OffSample/OffSample.p

Text File | 1994-11-18 | 44.3 KB | 1,532 lines | [TEXT/MPS ]

{------------------------------------------------------------------------------
#
#    Apple Macintosh Developer Technical Support
#
#    Offscreen Buffer Sample Application
#
#    OffSample
#
#    OffSample.p        -    Pascal Source
#
#    Copyright © 1989 Apple Computer, Inc.
#    All rights reserved.
#
#    Versions:
#                1.00                04/89
#                1.01                06/92
#
#    Components:
#                OffSample.p            April 1, 1989
#                OffSample.r            April 1, 1989
#                OffSample.h            April 1, 1989
#                OffSample.rsrc        April 1, 1989
#                POffSample.make        April 1, 1989
#
#    Requirements:
#                Offscreen.p            April 1, 1989
#                Offscreen.inc1.p    April 1, 1989
#                UFailure.p            November 1, 1988
#                UFailure.inc1.p        November 1, 1988
#                UFailure.a            November 1, 1988
#
#    OffSample demonstrates the usage of the Offscreen
#    unit. It shows how to use offscreen pixmaps and
#    bitmaps to produce flicker-free updating with a
#    minimum of re-structuring of code. OffSample attempts
#    to reduce the amount of 'knowledge' that it has of
#    the offscreen structure so as to minimize its
#    dependence on that unit.
#
#    OffSample emphasizes using the Offscreen unit; it
#    is not intended to be viewed as a complete application
#    from which to base some larger effort. Instead, its
#    method of using offscreen bitmaps and pixmaps should
#    be studied and adapted to other applications that
#    desire features such as flicker-free updating.
#
------------------------------------------------------------------------------}


PROGRAM OffSample;

USES
    Types, QuickDraw, Palettes, Events, Controls, Windows, TextEdit, Dialogs,
    Fonts, Lists, Menus, Resources, Scrap, ToolUtils,
    OSUtils, Files, Devices, DeskBus, DiskInit, Disks, Errors, Memory, Retrace, SegLoad, Serial,
    ShutDown, Slots, Sound, Start, Timer,
    Packages, ColorPicker, UFailure, Offscreen, Traps;

CONST

    kSysEnvironsVersion        = 1;

    kOSEvent                = app4Evt;        {event used by MultiFinder}
    kSuspendResumeMessage    = 1;            {high byte of suspend/resume event message}
    kResumeMask                = 1;            {bit of msg field for resume vs. suspend}

    kMinHeap                = 66 * 1024;

    kMinSpace                = 49 * 1024;

    kExtremeNeg                = -32768;
    kExtremePos                = 32767 - 1;    {required for old region bug}

    sErrStrings                = 128;            {error string STR#}
    eStandardErr            = 1;
    eWrongMachine            = 2;
    eSmallSize                = 3;
    eNoMemory                = 4;

    kNoBackBuff                = 128;
    kNoEditBuff                = 129;
    kTitle                    = 130;
    kColorPrompt            = 131;
    kNoWantBack                = 132;
    kNoWantEdit                = 133;

    kCMoof                    = 128;
    kGigantor                = 128;
    k1bitGigantor            = 129;

    rMenuBar                = 128;            {application's menu bar}
    rAboutAlert                = 128;            {about alert}
    rUserAlert                = 129;            {error user alert}
    rWindow                    = 128;            {application's window}

    mApple                    = 128;            {Apple menu}
    iAbout                    = 1;

    mFile                    = 129;            {File menu}
    iNew                    = 1;
    iClose                    = 4;
    iQuit                    = 12;

    mEdit                    = 130;            {Edit menu}
    iUndo                    = 1;
    iCut                    = 3;
    iCopy                    = 4;
    iPaste                    = 5;
    iClear                    = 6;

    mShape                    = 131;            {Shape menu}

    mSpecial                = 132;            {Special menu}
    iUseBack                = 1;
    iUseEdit                = 2;
    iPickColor                = 4;

    kDITop                    = $0050;
    kDILeft                    = $0070;

    kNotDrawn                = -1;
    kLastOne                = -2;

    kCursorDepth            = 2;
    kMemoryPolite            = TRUE;

    kFramePenH                = 2;
    kFramePenV                = 2;


TYPE

    Shapes            = (kOval, kRegion, kRRect, kPoly, kRect, kICON, kPICT);

    ShapeRecord        = RECORD
        next            : Shapes;        {when is it drawn?}
        extent            : Rect;            {where is it?}
    END;

    ShapeArray        = ARRAY [Shapes] OF ShapeRecord;

    {An OffscreenRecord contains the WindowRecord for one of our sample windows,
     as well as an offscreen handle for the background and an offscreen handle
     for the background plus the shape being created. It also has an array of
     shapes for this window, a pointer to the first shape, a pointer to the
     shape being edited, and a record of the last state of the buffers. For a
     similar example of extending a toolbox data structure, see how the Window
     Manager and Dialog Manager add fields to the GrafPort and WindowRecord,
     respectively.}

    OffscreenRecord    = RECORD
        fWindow        : WindowRecord;        {window data structure for toolbox use}
        fBackHandle    : Handle;            {offscreen pixmap that holds background}
        fEditHandle    : Handle;            {pixmap for background and shape being created}
        fShapes        : ShapeArray;        {the shapes for this window}
        fFirst        : Shapes;            {who is first?}
        fEdit        : Shapes;            {who is being edited?}
        fHasBack    : BOOLEAN;            {did it have a background buffer last time?}
        fHasEdit    : BOOLEAN;            {did it have a edit buffer last time?}
    END;
    OffscreenPeek    = ^OffscreenRecord;


VAR
    {The "g" prefix is used to emphasize that a variable is global.}

    gMac                : SysEnvRec;    {set up by Initialize}
    gHasWaitNextEvent    : BOOLEAN;        {set up by Initialize}
    gInBackground        : BOOLEAN;        {maintained by Initialize and DoEvent}

    gShape                : Shapes;        {current shape}
    gUseBack            : BOOLEAN;        {create background offscreen flag}
    gUseEdit            : BOOLEAN;        {create edit offscreen flag}
    gCursor                : CCrsrHandle;    {there can be ONLY one}
    gOughHandle            : Handle;        {offscreen handle for color cursor}
    gPICT                : PicHandle;    {Gigantor}
    gcicn                : CIconHandle;    {Moof!™}
    g1BitHandle            : Handle;        {for the color cursor mask}


{$S Initialize}
FUNCTION TrapAvailable(tNumber: INTEGER; tType: TrapType): BOOLEAN;

{Check to see if a given trap is implemented. This is only used by the
 Initialize routine in this program, so we put it in the Initialize segment.
 The recommended approach to see if a trap is implemented is to see if
 the address of the trap routine is the same as the address of the
 Unimplemented trap. Needs to be called after call to SysEnvirons so that
 it can check if a ToolTrap is out of range of a pre-MacII ROM.}

BEGIN
    IF (tType = ToolTrap) &
        (gMac.machineType > envMachUnknown) &
        (gMac.machineType < envMacII) THEN BEGIN        {it's a 512KE, Plus, or SE}
        tNumber := BAND(tNumber, $03FF);
        IF tNumber > $01FF THEN                            {which means the tool traps}
            tNumber := _Unimplemented;                    {only go to $01FF}
    END;
    TrapAvailable := NGetTrapAddress(tNumber, tType) <>
                        NGetTrapAddress(_Unimplemented, ToolTrap);
END; {TrapAvailable}


{$S Main}
PROCEDURE GetGlobalRect (window: WindowPtr; VAR globalRect: Rect);

{Return the portRect of window in global coordinates.}

VAR
    savePort    : GrafPtr;

BEGIN
    GetPort(savePort);
    SetPort(window);                    {so that the correct }
    globalRect := window^.portRect;        { coordinate system is used}
    WITH globalRect DO BEGIN
        LocalToGlobal(topLeft);
        LocalToGlobal(botRight);
    END;
    SetPort(savePort);
END; {GetGlobalRect}


{$S Main}
FUNCTION IsDAWindow (window: WindowPtr): BOOLEAN;

{Check if a window belongs to a desk accessory.}

BEGIN
    IF window = NIL THEN
        IsDAWindow := FALSE
    ELSE    {DA windows have negative windowKinds}
        IsDAWindow := WindowPeek(window)^.windowKind < 0;
END; {IsDAWindow}


{$S Main}
FUNCTION IsAppWindow (window: WindowPtr): BOOLEAN;

{Check to see if a window belongs to the application. If the window pointer
 passed was NIL, then it could not be an application window. WindowKinds
 that are negative belong to the system and windowKinds less than userKind
 are reserved by Apple except for windowKinds equal to dialogKind, which
 mean it is a dialog.}

BEGIN
    IF window = NIL THEN
        IsAppWindow := FALSE
    ELSE    {application windows have windowKinds >= userKind (8)}
        WITH WindowPeek(window)^ DO
            IsAppWindow := (windowKind = userKind);
END; {IsAppWindow}


{$S Main}
PROCEDURE FailNILMsg(p: UNIV Ptr; message: INTEGER);

{Check for NIL p and fail if so.}

BEGIN
    IF p = NIL THEN
        Failure(memFullErr, message);
END; {FailNILMsg}


{$S Main}
PROCEDURE AlertUser(error: INTEGER; message: LongInt);

{Display an alert to inform the user of an error. Message acts as an
 index into a STR# resource of error messages. If no message is given,
 i.e. = 0, then use a standard message. If error is not noErr then
 display it as well.}

VAR
    msg1, msg2    : Str255;
    itemHit        : INTEGER;
BEGIN
    IF message = 0 THEN message := eStandardErr;
    GetIndString(msg1, sErrStrings, message);
    IF error = noErr THEN
        msg2 := ''
    ELSE
        NumToString(error, msg2);
    ParamText(msg1, msg2, '', '');
    itemHit := Alert(rUserAlert, NIL);
END; {AlertUser}


{$S Main}
FUNCTION DoCloseWindow(window: WindowPtr) : BOOLEAN;

{Close a window.}

{At this point, if there was a document associated with a
 window, you could do any document saving processing if it is 'dirty'.
 DoCloseWindow would return TRUE if the window actually closes, i.e.,
 the user does not cancel from a save dialog. This result is handy when
 the user quits an application, but then cancels a save of a document
 associated with a window. We also added code to close the application
 window since otherwise, the termination routines would never stop looping,
 waiting for FrontWindow to return NIL.}

VAR
    pal    : PaletteHandle;

BEGIN
    DoCloseWindow := TRUE;
    IF IsDAWindow(window) THEN
        CloseDeskAcc(WindowPeek(window)^.windowKind);
    IF IsAppWindow(window) THEN BEGIN
        WITH OffscreenPeek(window)^ DO BEGIN
            DisposeOffscreen(fBackHandle);
            DisposeOffscreen(fEditHandle);
        END;
        IF gMac.hasColorQD THEN BEGIN
            pal := GetPalette(window);            {We must handle this ourselves,}
            DisposePalette(pal);                {since we may have done a GetPalette.}
        END;
        CloseWindow(window);                    {Since we provided our own storage.}
        DisposePtr(Ptr(window));
    END;
END; {DoCloseWindow}


{$S Main}
PROCEDURE EfficientConcat2 (VAR string1, string2: Str255);

{Do a more efficient concat than CONCAT since we know
 there are only two strings.}

VAR
    len1, len2    : INTEGER;

BEGIN
    len1 := LENGTH(string1);
    IF len1 < 255 THEN BEGIN
        len2 := LENGTH(string2);
        IF len1 + len2 > 255 THEN
            len2 := 255 - len1;
        BlockMove(@string2[1], @string1[1 + len1], len2);
        string1[0] := CHR(len1 + len2);
    END;
END; {EfficientConcat2}


{$S Main}
PROCEDURE AppendTitle (VAR title: Str255; id: INTEGER);

{Append the specified string resource data to the provided
 string.}


VAR
    aString    : StringHandle;

BEGIN
    aString := GetString(id);
    IF aString <> NIL THEN BEGIN
        HLock(Handle(aString));                {in case EfficientConcat2 is}
        EfficientConcat2(title, aString^^);
        HUnlock(Handle(aString));            {in a different segment}
    END;
END; {AppendTitle}


{$S Main}
PROCEDURE CheckTitle (window: WindowPtr; doCheck: BOOLEAN);

{Compare the prior state of the offscreen handles for
 window and change its title to reflect the new state.}

VAR
    aString                : StringHandle;
    title                : Str255;
    hasBack, hasEdit    : BOOLEAN;

BEGIN
    IF IsAppWindow(window) THEN
        WITH OffscreenPeek(window)^ DO BEGIN
            hasBack := (GetMap(fBackHandle) <> NIL);
            hasEdit := (GetMap(fEditHandle) <> NIL);
            IF (NOT doCheck) |                    {set title regardless}
            (fHasBack <> hasBack) |                {or if change}
            (fHasEdit <> hasEdit) THEN BEGIN    {in buffers}
                fHasBack := hasBack;
                fHasEdit := hasEdit;
                title := '';
                aString := GetString(kTitle);
                IF aString <> NIL THEN
                    title := aString^^;

                {If an offscreen handle is NIL, it means
                 that the creation of that offscreen handle
                 was disabled by the user. Once that is
                 done, the buffer will never be created.}

                IF fBackHandle = NIL THEN
                    AppendTitle(title, kNoWantBack)
                ELSE IF NOT hasBack THEN
                    AppendTitle(title, kNoBackBuff);
                IF fEditHandle = NIL THEN
                    AppendTitle(title, kNoWantEdit)
                ELSE IF NOT hasEdit THEN
                    AppendTitle(title, kNoEditBuff);
                SetWTitle(window, title);
            END;
        END;
END; {CheckTitle}


{$S Main}
PROCEDURE DrawShape (shape: Shapes; VAR extent: Rect);

{Draw the shape specified in the extent. Extent is a VAR
 parameter because the region and polygon are generated
 from the extent rect and the calculations might result
 in a final shape larger than the original extent.}

    PROCEDURE DoRegion;

    {Generate a region based on the extent.}

    VAR
        r        : Rect;
        rHandle    : RgnHandle;
        pHandle    : PolyHandle;

    BEGIN
        r := extent;
        rHandle := NewRgn;
        OpenRgn;

        FrameRect(extent);
        WITH r DO BEGIN
            top := top + ((bottom - top) DIV 3);
            bottom := top + ((bottom - top) DIV 2);
        END;
        FrameOval(r);
        pHandle := OpenPoly;
        WITH extent DO BEGIN
            MoveTo(left, top);
            LineTo(right, bottom);
            LineTo(left + (right - left) DIV 2, bottom - (bottom - top) DIV 3);
            LineTo(left, top);
        END;
        ClosePoly;
        FramePoly(pHandle);
        KillPoly(pHandle);

        CloseRgn(rHandle);
        extent := rHandle^^.rgnBBox;        {in case bigger than original rect}
        IF gMac.hasColorQD THEN
            PaintRgn(rHandle)
        ELSE
            FillRgn(rHandle, qd.black);
        ForeColor(blackColor);
        FrameRgn(rHandle);
        DisposeRgn(rHandle);
    END; {DoRegion}

    PROCEDURE DoPoly;

    {Generate a polygon based on the extent.}

    VAR
        pHandle    : PolyHandle;

    BEGIN
        pHandle := OpenPoly;
        WITH extent DO BEGIN
            MoveTo(left + (right - left) DIV 2, top);
            LineTo(right, bottom);
            LineTo(left, top + (bottom - top) DIV 3);
            LineTo(right, top + (bottom - top) DIV 3);
            LineTo(left, bottom);
            LineTo(left + (right - left) DIV 2, top);
        END;
        ClosePoly;
        extent := pHandle^^.polyBBox;        {in case bigger than original rect}
        IF gMac.hasColorQD THEN
            PaintPoly(pHandle)
        ELSE
            FillPoly(pHandle, qd.ltGray);
        ForeColor(blackColor);
        FramePoly(pHandle);
        KillPoly(pHandle);
    END; {DoPoly}

BEGIN
    PenNormal;
    PenSize(kFramePenH, kFramePenV);
    CASE shape OF
        kOval: BEGIN
            IF gMac.hasColorQD THEN
                PaintOval(extent)
            ELSE
                FillOval(extent, qd.white);
            ForeColor(blackColor);
            FrameOval(extent);
        END;
        kRegion:
            DoRegion;
        kRRect: BEGIN
            IF gMac.hasColorQD THEN
                PaintRoundRect(extent, 16, 16)
            ELSE
                FillRoundRect(extent, 16, 16, qd.gray);
            ForeColor(blackColor);
            FrameRoundRect(extent, 16, 16);
        END;
        kPoly:
            DoPoly;
        kRect: BEGIN
            IF gMac.hasColorQD THEN
                PaintRect(extent)
            ELSE
                FillRect(extent, qd.dkGray);
            ForeColor(blackColor);
            FrameRect(extent);
        END;
        kICON:
            IF gMac.hasColorQD THEN
                PlotCIcon(extent, gcicn)
            ELSE BEGIN
                HLock(Handle(gcicn));
                WITH gcicn^^ DO BEGIN
                {We cannot call PlotCIcon when Color QD is not
                 present, but we can still use the color icon
                 data.}
                    iconMask.baseAddr := @iconMaskData;
                    iconBMap.baseAddr := Ptr(ORD(@iconMaskData) + 128);
                    CopyMask(iconBMap, iconMask, qd.thePort^.portBits,
                                iconBMap.bounds, iconMask.bounds, extent);
                END;
                HUnlock(Handle(gcicn));
            END;
        kPICT:
            DrawPicture(gPICT, extent);
    END;
END; {DrawShape}


{$S Main}
FUNCTION GimmeBlackAndWhite(rgb: RGBColor; VAR position: LONGINT): BOOLEAN;

{This is a search proc that returns white only if the color is really white;
 otherwise it returns black. It is used to generate the mask for the color
 cursor. It boldly assumes that it is being called for a 1 bit deep map.}

BEGIN
    WITH rgb DO
        IF (red = $FFFF) & (green = $FFFF) & (blue = $FFFF) THEN
            position := 0                    {return white if it’s white}
        ELSE
            position := 1;                    {else return black for all other colors}
    GimmeBlackAndWhite := TRUE;
END; {GimmeBlackAndWhite}


{$S Main}
PROCEDURE SetObjCursor (window: WindowPtr);

{Build the color cursor. Note that this routine is only called
 in a Color QD environment, so it doesn't have to make the
 check. Note also that the cursors could have all been 'pre-
 built', thus making things more efficient, but this example
 shows that dynamic cursors can be implemented via pixmaps.}

VAR
    colors            : CTabHandle;
    pal                : PaletteHandle;
    rgb                : RGBColor;
    bounder, extent    : Rect;
    buffNotNeeded    : BOOLEAN;
    naughtyBits        : BitMap;
    oneBitPMap        : BitMapPtr;

BEGIN
    SetRect(bounder, 0, 0, 16, 16);
    pal := GetPalette(window);
    GetEntryColor(pal, ORD(gShape) + 2, rgb);    {get the color used for the shape}

    DisposeOffscreen(gOughHandle);                {get rid of old color table}
    colors := CTabHandle(NewHandleClear(SIZEOF(ColorTable)));
    FailNILMsg(colors, eNoMemory);
    colors^^.ctTable[0].rgb := rgb;                {stuff in the color we want}

    FailOSErr(NewOffscreen(bounder, kCursorDepth, colors,
                    NOT kMemoryPolite, buffNotNeeded,
                    gOughHandle));
    DisposeHandle(Handle(colors));

    HLock(Handle(gCursor));
    WITH gCursor^^ DO BEGIN
        crsrMap := PixMapHandle(RecoverHandle(Ptr(GetMap(gOughHandle))));
        crsrData := GetBitsHandle(gOughHandle);
        IF crsrData = NIL THEN BEGIN            {no handle to bits available-punt}
            SetCursor(qd.arrow);
            Exit(SetObjCursor);
        END;
        BeginOffscreenDrawing(gOughHandle, NIL);
        IF NOT (gShape IN [kICON, kPICT]) THEN BEGIN
            SetPt(crsrHotSpot, 0, 0);
            RGBForeColor(rgb);
            extent := bounder;
            InsetRect(extent, 3, 1);            {squeeze it a bit}
            DrawShape(gShape, extent);            {draw the cursor shape}
            PenNormal;
            ForeColor(blackColor);                {draw hot spot}
            MoveTo(0, 0);
            LineTo(0, 1);
        END ELSE BEGIN                            {use a plain cursor for icon/pict}
            SetPt(crsrHotSpot, 2, 2);
            PenNormal;
            ForeColor(blackColor);
            MoveTo(0, 0);
            LineTo(4, 4);
            MoveTo(4, 0);
            LineTo(0, 4);
        END;
        EndOffscreenDrawing(gOughHandle);
        WITH naughtyBits DO BEGIN                {build 1-bit image and mask}
            bounds := bounder;
            baseAddr := @crsr1Data;
            rowBytes := 2;
            CopyBits(BitMapPtr(crsrMap^)^, naughtyBits,
                        bounder, bounder, srcCopy, NIL);

            oneBitPMap :=  GetMap(g1BitHandle);
            oneBitPMap^.baseAddr := @crsrMask;
            AddSearch(@GimmeBlackAndWhite);
            CopyBits(BitMapPtr(crsrMap^)^, oneBitPMap^,
                        bounder, bounder, srcCopy, NIL);
            DelSearch(@GimmeBlackAndWhite);
        END;
        crsrXValid := 0;
        crsrID := GetCTSeed;
    END;
    HUnlock(Handle(gCursor));
END; {SetObjCursor}


{$S Main}
FUNCTION GetInvalExtent (window: WindowPtr; shape: Shapes) : Rect;

{Return the shape's extent, adjusted for the pensize of the frame.}

VAR
    r    : Rect;

BEGIN
    r := OffscreenPeek(window)^.fShapes[shape].extent;
    WITH r DO BEGIN
        right := right + kFramePenH;
        bottom := bottom + kFramePenV;
    END;
    GetInvalExtent := r;
END; {GetInvalExtent}


{$S Main}
PROCEDURE ChangeColor (window: WindowPtr);

{Display the Color ColorPicker dialog. Note that this is
 only called in Color QD environments.}

VAR
    pal                    : PaletteHandle;
    inColor, outColor    : RGBColor;
    where                : Point;
    r                    : Rect;
    aString                : StringHandle;
    prompt                : Str255;

BEGIN
    pal := GetPalette(window);
    WITH OffscreenPeek(window)^ DO BEGIN
        GetEntryColor(pal, ORD(gShape) + 2, inColor);
        SetPt(where, kDILeft, kDITop);
        aString := GetString(kColorPrompt);
        IF aString <> NIL THEN
            prompt := aString^^
        ELSE
            prompt := '';
        IF GetColor(where, prompt, inColor, outColor) THEN BEGIN
            SetEntryColor(pal, ORD(gShape) + 2, outColor);
            ActivatePalette(window);
            SetObjCursor(window);
            IF NOT (fShapes[gShape].next = Shapes(kNotDrawn)) THEN BEGIN
                r := GetInvalExtent(window, gShape);
                SetPort(window);
                InvalRect(r);
            END;
        END;
    END;
END; {ChangeColor}


{$S Main}
PROCEDURE DoNewWindow;

{We will allocate our own window storage instead of letting the Window
 Manager do it for two reasons. One, GetNewWindow locks the 'WIND' resource
 handle before calling NewWindow and this can lead to heap fragmentation
 in low memory situations. Two, it takes just as much time for NewWindow
 to get the memory as it does for us to get it. Three, there are THREE
 reasons we will allocate our own window storage instead of letting the
 Window Manager do it. One, GetNewWindow locks etc. etc. Two, it takes
 just as much time, etc. etc. And three, this way we can allocate larger records
 where the extra space can be used to connect other, related data structures.
 Four, there is no fourth reason.}

VAR
    p                : Ptr;
    window            : WindowPtr;
    noBuffsPlease    : BOOLEAN;
    title            : Str255;
    shape            : Shapes;
    emptyRect        : Rect;

BEGIN
    p := NewPtr(SIZEOF(OffscreenRecord));
    FailNILMsg(p, eNoMemory);
    window := NIL;
    IF gMac.hasColorQD THEN
        window := GetNewCWindow(rWindow, p, WindowPtr(-1))
    ELSE
        window := GetNewWindow(rWindow, p, WindowPtr(-1));
    FailNILMsg(window, eNoMemory);

    WITH OffscreenPeek(window)^ DO BEGIN
        fBackHandle := NIL;
        fEditHandle := NIL;
        fHasBack := FALSE;
        fHasEdit := FALSE;
        IF gUseBack THEN
            IF NewOffscreenForWindow(window, noBuffsPlease, fBackHandle) = noErr THEN;
        IF gUseEdit THEN
            IF NewOffscreenForWindow(window, noBuffsPlease, fEditHandle) = noErr THEN;
        SetRect(emptyRect, 0, 0, 0, 0);
        FOR shape := kOval TO kPICT DO BEGIN
            fShapes[shape].next := Shapes(kNotDrawn);
            fShapes[shape].extent := emptyRect;
        END;
        fFirst := Shapes(kNotDrawn);
        fEdit := Shapes(kNotDrawn);
    END;

    CheckTitle(window, FALSE);
    IF gMac.hasColorQD THEN
        SetObjCursor(window);
END; {DoNewWindow}


{$S Initialize}
PROCEDURE Initialize;

{Set up the whole world, including global variables, Toolbox managers,
 and menus. We also create one application window at this time.
 Since window storage is non-relocateable, how and when to allocate space
 for windows is very important so that heap fragmentation does not occur.
 Window storage can differ widely amongst applications depending on how many
 windows are created and disposed. If a failure occurs here, we will consider
 that the application is in such bad shape that we should just exit. Your error
 handling may differ, but the checks should still be made.}

TYPE
    crsColors = ARRAY[0..2] OF ColorSpec;

VAR
    menuBar            : Handle;
    ignoreError        : OSErr;
    total, contig    : LongInt;
    ignoreResult    : BOOLEAN;
    event            : EventRecord;
    count            : INTEGER;
    fi                : FailInfo;
    colors            : CTabHandle;
    bounder            : Rect;
    buffNotNeeded    : BOOLEAN;

    PROCEDURE HandleErr(error: INTEGER; message: LongInt);
    BEGIN
        IF error > 0 THEN
            AlertUser(0, error)
        ELSE
            AlertUser(error, message);
        ExitToShell;
    END; {HandleErr}

BEGIN
    gInBackground := FALSE;

    InitGraf(@qd.thePort);
    InitFonts;
    InitWindows;
    InitMenus;
    TEInit;
    InitDialogs(NIL);
    InitCursor;

    InitOffscreen;

    {Call OpenDriver('.MPP', refnum) at this point to initialize AppleTalk,
     if you are using it.}

    {NOTE -- It is no longer necessary, and actually unhealthy, to check
     PortBUse and SPConfig before opening AppleTalk. The drivers are capable
     of checking for port availability themselves.}

    {This next bit of code is necessary to allow the default button of our
     alert to be outlined.}

    FOR count := 1 TO 3 DO
        ignoreResult := EventAvail(everyEvent, event);

    CatchFailures(fi, HandleErr);

    {Ignore the error returned from SysEnvirons; even if an error occurred,
     the SysEnvirons glue will fill in the SysEnvRec. You can save a redundant
     call to SysEnvirons by calling it after initializing AppleTalk.}

    ignoreError := SysEnvirons(kSysEnvironsVersion, gMac);

    {Make sure that the machine has at least 128K ROMs. If it doesn't, exit.}

    IF gMac.machineType < 0 THEN
        Failure(0, eWrongMachine);

    {Move TrapAvailable call to after SysEnvirons so that we can tell
     in TrapAvailable if a tool trap value is out of range.}

    gHasWaitNextEvent := TrapAvailable(_WaitNextEvent, ToolTrap);

    {First check the size of the application heap against a value
     that you have determined is the smallest heap the application can reasonably
     work in. This number should be derived by examining the size of the heap that
     is actually provided by MultiFinder when the minimum size requested is used.
     The derivation of the minimum size requested from MultiFinder is described
     in Sample.h. The check should be made because the preferred size can end up
     being set smaller than the minimum size by the user. This extra check acts to
     insure that your application is starting from a solid memory foundation.}

    IF ORD(GetApplLimit) - ORD(ApplicationZone) < kMinHeap THEN
        Failure(0, eSmallSize);

    {Next, make sure that enough memory is free for your application to run. It
     is possible for a situation to arise where the heap may have been of required
     size, but a large scrap was loaded which left too little memory. To check for
     this, call PurgeSpace and compare the result with a value that you have determined
     is the minimum amount of free memory your application needs at initialization.
     This number can be derived several different ways. One way that is fairly
     straightforward is to run the application in the minimum size configuration
     as described previously. Call PurgeSpace at initialization and examine the value
     returned. However, you should make sure that this result is not being modified
     by the scrap's presence. You can do that by calling ZeroScrap before calling
     PurgeSpace. Make sure to remove that call before shipping, though.}

    PurgeSpace(total, contig);
    IF total < kMinSpace THEN
        Failure(0, eNoMemory);

    {The extra benefit to waitng until after the Toolbox Managers have been initialized
     before checking memory is that we can now give the user an alert to tell him what
     happened. Although it is possible that the memory situation could be worsened by
     displaying an alert, MultiFinder would gracefully exit the application with
     an informative alert if memory became critical. Here we are acting more
     in a preventative manner to avoid future disaster from low-memory problems.}

    menuBar := GetNewMBar(rMenuBar);        {read menus into menu bar}
    FailNILMsg(menuBar, eNoMemory);
    SetMenuBar(menuBar);                    {install menus}
    DisposeHandle(menuBar);
    AppendResMenu(GetMenuHandle(mApple), 'DRVR');    {add DA names to Apple menu}
    DrawMenuBar;
    gShape := kOval;
    gUseBack := TRUE;
    gUseEdit := TRUE;
    gOughHandle := NIL;

    {Get the 'Moof' icon. If the environment supports Color QD,
     we'll get the color icon. If Color QD is not supported,
     we'll still get the color icon, but use it differently.}

    IF gMac.hasColorQD THEN BEGIN
        gcicn := GetCIcon(kCMoof);
        FailNILMsg(gcicn, eNoMemory);
    END ELSE BEGIN
        gcicn := CIconHandle(GetResource('cicn', kCMoof));
        FailNILMsg(gcicn, eNoMemory);
    END;

    {If Color QD is supported, we'll get an 8-bit PICT of
     Gigantor. If it isn't supported, we'll get a PICT
     that looks better in non-color ports/}

    IF gMac.hasColorQD THEN
        gPICT := GetPicture(kGigantor)
    ELSE
        gPICT := GetPicture(k1bitGigantor);
    FailNILMsg(gPICT, eNoMemory);

    {If Color QD is supported, we'll set up a color cursor
     that will be modified later. Otherwise, nothing
     happens. We'll also set up a 1-bit offscreen to
     make a cursor mask.}

    IF gMac.hasColorQD THEN BEGIN
        gCursor := CCrsrHandle(NewHandleClear(SIZEOF(CCrsr)));
        FailNILMsg(gCursor, eNoMemory);
        MoveHHi(Handle(gCursor));
        HLock(Handle(gCursor));
        WITH gCursor^^ DO BEGIN
            crsrType := $8001;
            crsrXData := NewHandle(0);
        END;
        HUnlock(Handle(gCursor));
        colors := CTabHandle(NewHandleClear(SIZEOF(ColorTable)));
        FailNILMsg(colors, eNoMemory);
        SetRect(bounder, 0, 0, 16, 16);

        {For this one bit deep offscreen guy (used to make cursor masks)
         we pass in a zeroed but otherwise unitialized color table. Since
         the map’s ctable will only have B&W anyway, it doesn’t matter.}

        FailOSErr(NewOffscreen(bounder, 1, colors,
                        NOT kMemoryPolite, buffNotNeeded,
                        g1BitHandle));
        DisposeHandle(Handle(colors));
    END;

    DoNewWindow;                            {create a new window right away}
END; {Initialize}


{$S Main}
PROCEDURE Terminate;

{Clean up the application and exits. We close all of the windows so that
 they can update their documents, if any.
 If we find out that a cancel has occurred, we won't exit to the
 shell, but will return instead.}

VAR
    aWindow    : WindowPtr;
    closed    : BOOLEAN;

BEGIN
    closed := TRUE;
    REPEAT
        aWindow := FrontWindow;                    {get the current front window}
        IF aWindow <> NIL THEN
            closed := DoCloseWindow(aWindow);    {close this window}
    UNTIL (NOT closed) | (aWindow = NIL);        {do all windows}
    IF closed THEN
        ExitToShell;                            {exit if no cancellation}
END; {Terminate}


{$S Main}
PROCEDURE AdjustMenus;

{Enable and disable menus based on the current state.
 The user can only select enabled menu items. We set up all the menu items
 before calling MenuSelect or MenuKey, since these are the only times that
 a menu item can be selected. Note that MenuSelect is also the only time
 the user will see menu items. This approach to deciding what enable/
 disable state a menu item has the advantage of concentrating all the decision-
 making in one routine, as opposed to being spread throughout the application.
 Other application designs may take a different approach that may or may not be
 just as valid.}

VAR
    window            : WindowPtr;
    menu            : MenuHandle;

BEGIN
    window := FrontWindow;

    menu := GetMenuHandle(mFile);
    IF IsDAWindow(window) |
        IsAppWindow(window) THEN            {we can allow DAs to be closed from the menu}
        EnableItem(menu, iClose)
    ELSE
        DisableItem(menu, iClose);

    menu := GetMenuHandle(mEdit);
    IF IsDAWindow(window) THEN BEGIN        {a desk accessory might need the edit menu}
        EnableItem(menu, iUndo);
        EnableItem(menu, iCut);
        EnableItem(menu, iCopy);
        EnableItem(menu, iPaste);
        EnableItem(menu, iClear);
    END ELSE BEGIN                            {but we know we do not}
        DisableItem(menu, iUndo);
        DisableItem(menu, iCut);
        DisableItem(menu, iCopy);
        DisableItem(menu, iClear);
        DisableItem(menu, iPaste);
    END;

    menu := GetMenuHandle(mSpecial);
    IF gMac.hasColorQD & IsAppWindow(window) THEN
        EnableItem(menu, iPickColor)        {color can change only if we are top}
    ELSE
        DisableItem(menu, iPickColor);
END; {AdjustMenus}


{$S Main}
PROCEDURE DoMenuCommand(menuResult: LONGINT);

{This is called when an item is chosen from the menu bar (after calling
 MenuSelect or MenuKey). It performs the right operation for each command.
 It is good to have both the result of MenuSelect and MenuKey go to
 one routine like this to keep everything organized.}

VAR
    menuID            : INTEGER;        {the resource ID of the selected menu}
    menuItem        : INTEGER;        {the item number of the selected menu}
    int                : INTEGER;
    str                : Str255;
    ignore            : BOOLEAN;

BEGIN
    menuID := HiWord(menuResult);    {use built-ins (for efficiency)...}
    menuItem := LoWord(menuResult);    {to get menu item number and menu number}
    CASE menuID OF
        mApple:
            CASE menuItem OF
                iAbout:                {bring up alert for About}
                    int := Alert(rAboutAlert, NIL);
                OTHERWISE BEGIN        {all non-About items in this menu are DAs}
                    GetMenuItemText(GetMenuHandle(mApple), menuItem, str);
                    int := OpenDeskAcc(str);
                END;
            END;
        mFile:
            CASE menuItem OF
                iNew:
                    DoNewWindow;
                iClose:
                    ignore := DoCloseWindow(FrontWindow); {we don't care if cancelled}
                iQuit:
                    Terminate;
            END;
        mEdit:                        {call SystemEdit for DA editing & MultiFinder}
            ignore := SystemEdit(menuItem-1);    {since we don't do any editing}
        mShape:
            IF gShape <> Shapes(menuItem - 1) THEN BEGIN
                CheckItem(GetMenuHandle(mShape), ORD(gShape) + 1, FALSE);
                gShape := Shapes(menuItem - 1);        {the shape is the item}
                CheckItem(GetMenuHandle(mShape), ORD(gShape) + 1, TRUE);
                IF gMac.hasColorQD & IsAppWindow(FrontWindow) THEN
                    SetObjCursor(FrontWindow);
            END;
        mSpecial:
            CASE menuItem OF
                iUseBack: BEGIN
                    gUseBack := NOT gUseBack;
                    CheckItem(GetMenuHandle(mSpecial), iUseBack, gUseBack);
                END;
                iUseEdit: BEGIN
                    gUseEdit := NOT gUseEdit;
                    CheckItem(GetMenuHandle(mSpecial), iUseEdit, gUseEdit);
                END;
                iPickColor:
                    ChangeColor(FrontWindow);
            END;
    END;
    HiliteMenu(0);                    {unhighlight what MenuSelect (or MenuKey) hilited}
END; {DoMenuCommand}


{$S Main}
PROCEDURE GoThroughShapes (PROCEDURE WhatToDo(shape: Shapes); window: WindowPtr);

{Go through the list of shapes for window and
 call WhatToDo, passing the shape we are on
 each time.}

VAR
    theShape    : Shapes;

BEGIN
    WITH OffscreenPeek(window)^ DO
        IF ORD(fFirst) <> kNotDrawn THEN BEGIN
            theShape := fFirst;
            REPEAT
                WhatToDo(theShape);
                theShape := fShapes[theShape].next;
            UNTIL ORD(theShape) = kLastOne;
        END;
END; {GoThroughShapes}


{$S Main}
PROCEDURE DrawAllShapes (window: WindowPtr; doEdit: BOOLEAN);

{Draw either the currently edited shape or all the shapes
 in the window's list. Called by DrawWindow.}

VAR
    area    : Rect;

    PROCEDURE AndDrawThem (shape: Shapes);

    VAR
        r    : Rect;

    BEGIN
        WITH OffscreenPeek(window)^ DO
            IF shape <> fEdit THEN BEGIN
                IF SectRect(OffscreenPeek(window)^.fShapes[shape].extent, area, r)
                    THEN BEGIN
                    IF gMac.hasColorQD THEN
                        PmForeColor(ORD(shape) + 2);
                    DrawShape(shape, OffscreenPeek(window)^.fShapes[shape].extent);
                END;
            END;
    END;

BEGIN
    SetPort(window);
    IF doEdit THEN BEGIN
        WITH OffscreenPeek(window)^ DO                {draw edit shape}
            IF ORD(fEdit) <> kNotDrawn THEN BEGIN
                IF gMac.hasColorQD THEN
                    PmForeColor(ORD(fEdit) + 2);
                DrawShape(fEdit, OffscreenPeek(window)^.fShapes[fEdit].extent);
            END;
    END ELSE BEGIN
        area := window^.visRgn^^.rgnBBox;
        GoThroughShapes(AndDrawThem, window);
    END;
END; {DrawAllShapes}


{$S Main}
PROCEDURE DrawWindow(window: WindowPtr);

{The core application window updating routine. Understands about Offscreen
 setup, (in this case, two nested offscreen buffers), and what needs to
 be drawn, in this case, a whole bunch of shapes. Called from two routines,
 DoUpdate and DoContentClick. The way it works is first, by calling
 BeginUpdateOffscreen on fEditHandle, the drawing is redirected to
 the 'edit' offscreen pixmap. Next, if any drawing needs to be done
 in the 'background' pixmap, then by calling BeginOffscreenDrawing on
 fBackHandle, drawing is further redirected. All the shapes that exist
 but are not the one being edited (i.e., the background) are drawn here
 and the EndOffscreenDrawing causes the redirecting to cease. Then the
 pixmap is copybitsed into the next outer layer of drawing, whether that
 is the 'edit' offscreen pixmap or the window itself. There, the shape
 being edited is drawn. Finally, EndUpdateOffscreen is called to cease
 that layer of redirection and copybits the 'edit' offscreen to the window.
 The way this is designed, it all still works if either or both of the
 offscreen pixmaps is missing.}

VAR
    globalRect    : Rect;
    drawNeeded    : BOOLEAN;
    backMap        : BitMapPtr;

BEGIN
    GetGlobalRect(window, globalRect);
    WITH OffscreenPeek(window)^ DO BEGIN
        IF CheckBoundsOffscreen(fEditHandle, globalRect, drawNeeded) <> noErr THEN {do nada};
        SetPort(window);
        BeginUpdateOffscreen(fEditHandle, window);    {this sets up the visRgn}

        IF CheckBoundsOffscreen(fBackHandle, globalRect, drawNeeded) <> noErr THEN
                                                    {do nada};
        IF drawNeeded THEN BEGIN                    {draw if updating needs to be done}
            BeginOffscreenDrawing(fBackHandle, window);
            EraseRect(window^.portRect);            {clear out any garbage that might}
            DrawAllShapes(window, FALSE);            {be left behind and draw the}
            EndOffscreenDrawing(fBackHandle);        {'background'}
        END;
        backMap := GetMap(fBackHandle);
        IF backMap <> NIL THEN BEGIN
            ForeColor(blackColor);
            BackColor(whiteColor);                    {so funny colorization doesn't happen}
            WITH window^ DO BEGIN
                CopyBits(backMap^, portBits, portRect, portRect, srcCopy, NIL);
                ValidRectOffscreen(fBackHandle, NIL, portRect);
            END;
        END;
        DrawAllShapes(window, TRUE);                {only draw the edited shape}

        EndUpdateOffscreen(fEditHandle, window);
        CheckTitle(window, TRUE);                    {buffers may have changed}
    END;
END; {DrawWindow}


{$S Main}
PROCEDURE DoContentClick (window: WindowPtr; event: EventRecord);

{This is called when a mouse-down event occurs in the content of a window.
 Other applications might want to call FindControl, TEClick, etc., to
 further process the click. In Offsample, a user click in the content
 region means a shape is to be added or changed.}

VAR
    oldRect, newRect        : Rect;
    anchorPt, oldPt, nextPt    : Point;
    lastShape                : Shapes;
    first                    : BOOLEAN;

    PROCEDURE AndReorderThem (shape: Shapes);

    {Remove the edited shape from the linked list of shapes.}

    BEGIN
        WITH OffscreenPeek(window)^ DO
            IF shape <> gShape THEN
                lastShape := shape
            ELSE
                IF fFirst = shape THEN
                    fFirst := fShapes[shape].next
                ELSE
                    fShapes[lastShape].next := fShapes[shape].next;
    END; {AndReorderThem}

BEGIN
    IF IsAppWindow(window) THEN
        WITH OffscreenPeek(window)^ DO BEGIN
            anchorPt := event.where;
            GlobalToLocal(anchorPt);
            oldPt := anchorPt;

            {If the shape being edited existed previously, we need
             to invalidate its old position so that it gets
             'erased'.}

            IF ORD(fShapes[gShape].next) <> kNotDrawn THEN BEGIN
                oldRect := GetInvalExtent(window, gShape);
                InvalRectOffscreen(fBackHandle, NIL, oldRect);
                InvalRectOffscreen(fEditHandle, window, oldRect);
            END;
            fEdit := gShape;                            {flag this shape as edited}
            lastShape := Shapes(kLastOne);
            GoThroughShapes(AndReorderThem, window);
            IF ORD(lastShape) <> kLastOne THEN
                fShapes[lastShape].next := gShape        {make edited shape last}
            ELSE
                fFirst := gShape;                        {or if only shape, first}
            fShapes[gShape].next := Shapes(kLastOne);
            Pt2Rect(anchorPt, anchorPt, oldRect);
            first := TRUE;                                {indicate first time though loop}
            WHILE WaitMouseUp DO BEGIN                    {while the mouse is down…}
                GetMouse(nextPt);
                IF first | (NOT EqualPt(oldPt, nextPt)) THEN BEGIN
                    first := FALSE;                        {no longer first time through loop}
                    oldPt := nextPt;
                    CASE gShape OF
                        kOval,                            {build a rectangle for these}
                        kRegion,                        {from the anchor point and}
                        kRRect,                            {the current point}
                        kPoly,
                        kRect:
                            Pt2Rect(anchorPt, nextPt, newRect);
                        kICON:                            {rect from current position}
                            WITH nextPt, newRect DO BEGIN
                                top := v;
                                left := h;
                                bottom := top + 32;
                                right := left + 32;
                            END;
                        kPICT:                            {rect from current position}
                            WITH nextPt, newRect DO BEGIN
                                newRect := gPICT^^.picFrame;
                                OffsetRect(newRect, -left, -top);
                                OffsetRect(newRect, h, v);
                            END;
                    END;
                    fShapes[gShape].extent := newRect;
                    UnionRect(newRect, oldRect, oldRect);

                    {In the case of the 'stretchable' shapes whose extents are
                     built from the anchor point and the current point, doing
                     a UnionRect is pretty close to being as efficient as doing
                     a UnionRgn with two regions that are shaped like the old
                     and new extents. However, a case can be made for using
                     regions for the icon and the picture since they move around
                     instead of 'stretching'. The effect of extra, unnecessary
                     invalidation is, of course, most noticeable when there is
                     no edit offscreen and the icon/picture is moved around
                     rapidly. Changing the code to use regions is LEFT AS AN
                     EXERCISE FOR THE READER, Ha-Ha-Ha.}

                    InvalRectOffscreen(fEditHandle, window, oldRect);
                    DrawWindow(window);
                    oldRect := GetInvalExtent(window, gShape);
                END;
            END;
            fEdit := Shapes(kNotDrawn);
            oldRect := GetInvalExtent(window, gShape);
            InvalRectOffscreen(fBackHandle, NIL, oldRect);
        END;
END; {DoContentClick}


{$S Main}
PROCEDURE DoUpdate(window: WindowPtr);

{This is called when an update event is received for a window.
 It calls DrawWindow to draw the contents of an application window.}

BEGIN
    IF IsAppWindow(window) THEN
        DrawWindow(window);
END; {DoUpdate}


{$S Main}
PROCEDURE DoActivate(window: WindowPtr; becomingActive: BOOLEAN);

{This is called when a window is activated or deactivated.}

BEGIN
    IF IsAppWindow(window) THEN
        IF gMac.hasColorQD & becomingActive THEN
            SetObjCursor(window);
END; {DoActivate}


{$S Main}
PROCEDURE AdjustCursor(region: RgnHandle);

{Change the cursor's shape, depending on its position. This also calculates the region
 where the current cursor resides (for WaitNextEvent). If the mouse is ever outside of
 that region, an event is generated, causing this routine to be called. This
 allows us to change the region to the region the mouse is currently in. If
 there is more to the event than just “the mouse moved”, we get called before the
 event is processed to make sure the cursor is the right one. In any (ahem) event,
 this is called again before we fall back into WNE.}

VAR
    window                : WindowPtr;
    arrowRgn            : RgnHandle;
    shapeRgn            : RgnHandle;
    globalPortRect        : Rect;
    mouse                : Point;

BEGIN
    window := FrontWindow;
    {we only adjust the cursor when we are in front}
    IF (NOT gInBackground) AND (NOT IsDAWindow(window)) THEN BEGIN
        GetMouse(mouse);
        LocalToGlobal(mouse);

        {calculate regions for different cursor shapes}
        arrowRgn := NewRgn;
        shapeRgn := NewRgn;

        {start with a big, big rectangular region}
        SetRectRgn(arrowRgn, kExtremeNeg, kExtremeNeg,
                            kExtremePos, kExtremePos);

        {calculate shapeRgn}
        IF IsAppWindow(window) THEN BEGIN
            SetPort(window);            {make a global version of the portRect}
            IF gMac.hasColorQD THEN
                WITH CGrafPtr(window)^ DO
                    SetOrigin(-portPixMap^^.bounds.left, -portPixMap^^.bounds.top)
            ELSE
                WITH window^.portBits.bounds DO
                    SetOrigin(-left, -top);
            globalPortRect := window^.portRect;
            RectRgn(shapeRgn, globalPortRect);
            SectRgn(shapeRgn, window^.visRgn, shapeRgn);
            SetOrigin(0, 0);
        END;

        {subtract other regions from arrowRgn}
        DiffRgn(arrowRgn, shapeRgn, arrowRgn);

        {change the cursor and the region parameter}
        IF PtInRgn(mouse, shapeRgn) THEN BEGIN
            IF gMac.hasColorQD THEN
                SetCCursor(gCursor)
            ELSE
                SetCursor(GetCursor(crossCursor)^^);
            CopyRgn(shapeRgn, region);
        END ELSE BEGIN
            SetCursor(qd.arrow);
            CopyRgn(arrowRgn, region);
        END;

        {get rid of our local regions}
        DisposeRgn(arrowRgn);
        DisposeRgn(shapeRgn);
    END;
END; {AdjustCursor}


{$S Main}
PROCEDURE DoEvent(event: EventRecord);

{Do the right thing for an event. Determine what kind of event it is, and call
 the appropriate routines.}

VAR
    part, err    : INTEGER;
    window        : WindowPtr;
    ignore        : BOOLEAN;
    key            : CHAR;
    aPoint        : Point;
    fi            : FailInfo;

    PROCEDURE HandleErr(error: INTEGER; message: LongInt);
    BEGIN
        IF error > 0 THEN
            AlertUser(0, error)
        ELSE
            AlertUser(error, message);
        EXIT(DoEvent);
    END; {HandleErr}

BEGIN
    CatchFailures(fi, HandleErr);
    CASE event.what OF
        mouseDown: BEGIN
            part := FindWindow(event.where, window);
            CASE part OF
                inMenuBar: BEGIN            {process the menu command}
                    AdjustMenus;
                    DoMenuCommand(MenuSelect(event.where));
                END;
                inSysWindow:                {let the system handle the mouseDown}
                    SystemClick(event, window);
                inContent:
                    IF window <> FrontWindow THEN BEGIN
                        SelectWindow(window);
                        {DoEvent(event);}    {use this line for "do first click"}
                    END ELSE
                        DoContentClick(window, event);
                inDrag:                        {pass screenBits.bounds to get all gDevices}
                    DragWindow(window, event.where, qd.screenBits.bounds);
                inGrow:;
                inZoomIn, inZoomOut:;
                inGoAway:
                    IF TrackGoAway(window, event.where) THEN
                        ignore := DoCloseWindow(window);
            END;
        END;
        keyDown, autoKey: BEGIN                {check for menukey equivalents}
            key := CHR(BAnd(event.message, charCodeMask));
            IF BAnd(event.modifiers, cmdKey) <> 0 THEN    {Command key down}
                IF event.what = keyDown THEN BEGIN
                    AdjustMenus;            {enable/disable/check menu items properly}
                    DoMenuCommand(MenuKey(key));
                END;
        END;                                {call DoActivate with the window and...}
        activateEvt:                        {TRUE for activate, FALSE for deactivate}
            DoActivate(WindowPtr(event.message), BAnd(event.modifiers, activeFlag) <> 0);
        updateEvt:                          {call DoUpdate with the window to update}
            DoUpdate(WindowPtr(event.message));
        diskEvt:
            IF HiWord(event.message) <> noErr THEN BEGIN
                SetPt(aPoint, kDILeft, kDITop);
                err := DIBadMount(aPoint, event.message);
            END;
        kOSEvent:
            CASE BAnd(BRotL(event.message, 8), $FF) OF    {high byte of message}
                kSuspendResumeMessage: BEGIN
                    gInBackground := BAnd(event.message, kResumeMask) = 0;
                    DoActivate(FrontWindow, NOT gInBackground);
                END;
            END;
    END;
    Success(fi);
END; {DoEvent}


{$S Main}
PROCEDURE EventLoop;

{Get events forever, and handle them by calling DoEvent.
 Get the events by calling WaitNextEvent, if it's available, otherwise
 by calling GetNextEvent. Also call AdjustCursor each time through the loop.}

VAR
    cursorRgn    : RgnHandle;
    gotEvent    : BOOLEAN;
    event        : EventRecord;

BEGIN
    cursorRgn := NewRgn;            {we’ll pass WNE an empty region the 1st time thru}
    REPEAT
        IF gHasWaitNextEvent THEN {put us 'asleep' forever under MultiFinder}
            gotEvent := WaitNextEvent(everyEvent, event, MAXLONGINT, cursorRgn)
        ELSE BEGIN
            SystemTask;                {must be called if using GetNextEvent}
            gotEvent := GetNextEvent(everyEvent, event);
        END;
        IF gotEvent THEN BEGIN
            AdjustCursor(cursorRgn); {make sure we have the right cursor}
            DoEvent(event);
        END;
        AdjustCursor(cursorRgn);
    UNTIL FALSE;                    {loop forever; we quit through an ExitToShell}
END; {EventLoop}


PROCEDURE _DataInit; EXTERNAL;

{This routine is part of the MPW runtime library. This external
 reference to it is done so that we can unload its segment, %A5Init.}

{$S Main}
BEGIN
    UnloadSeg(@_DataInit);    {note that _DataInit must not be in Main!}

    MoreMasters;
    MoreMasters;
    MoreMasters;            {prepare for handles used by Offscreen}

    {If you have stack requirements that differ from the default,
     then you could use SetApplLimit to increase StackSpace at
     this point, before calling MaxApplZone.}

    MaxApplZone;            {expand the heap so code segments load at the top}

    InitSignals;
    Initialize;                {initialize the program}
    UnloadSeg(@Initialize);    {note that Initialize must not be in Main!}

    EventLoop;                {call the main event loop}
END.