// hack.  If god had meant programmers to mess with the menu bar, he'd have 

// provided a menu manager routine to accomplish this.

//

// Why is this code so skanky?

// ¥ it relies on static variable

// ¥ it relies on the complier auto initializing new variables to nil

//   to ensure that the regions get corrected properly

// ¥ it relies on manipulating low memory globals to which there may be no

//   access in future

// ¥ it doesn't really work too well (try a context switch, the grayrgn

//   needs fixing up when you switch back)

//

#include <LowMem.h>

#include <Windows.h>

#include "tumbler_hidemenubar.h"

static Boolean      pMbarIsVisible = true ;

static short        pOldMBarHeight = 0 ;        // saves the menu bar height

static RgnHandle    pOldGrayRgn = nil;

static RgnHandle    pMenuRgn = nil ;

static Rect         pMenuRect ;

static RgnHandle    pCopyGrayRgn ;

void ToggleMenuBar(void)

{

    WindowRef           frontWindow ;

    if((frontWindow = (WindowRef)FrontWindow()) == nil)

        return ;

    if( pOldGrayRgn == nil ) {

        pOldGrayRgn = NewRgn() ;

    }

    if( pMenuRgn == nil ) {

        pMenuRgn = NewRgn() ;

    }   

    if( pOldMBarHeight == 0 ) {

        pOldMBarHeight = LMGetMBarHeight() ;

    }

    if( pMbarIsVisible ) {

        // hide the menubar

        // store the grayrgn

        CopyRgn(GetGrayRgn(), pOldGrayRgn);

        // reset the menu bar height

        LMSetMBarHeight(0) ;

        // save the menu rect

        pMenuRect = qd.screenBits.bounds;

        pMenuRect.bottom = pOldMBarHeight;

        RectRgn(pMenuRgn, &pMenuRect);

        // and add this to the global grayrgn

        pCopyGrayRgn = GetGrayRgn() ;

        UnionRgn(pCopyGrayRgn, pMenuRgn, pCopyGrayRgn);

        LMSetGrayRgn( pCopyGrayRgn ) ;

        PaintBehind( frontWindow, pMenuRgn);

        CalcVisBehind( frontWindow, pMenuRgn);

    }

    else {

        // Show the menubar

        // reset the menu bar height

        LMSetMBarHeight( pOldMBarHeight );

        // update the grayrgn

        XorRgn(pCopyGrayRgn,pMenuRgn,pCopyGrayRgn) ;

        LMSetGrayRgn( pCopyGrayRgn ) ;

        // calc the rect occupied by the menu bar

        pMenuRect = qd.screenBits.bounds;

        pMenuRect.bottom = pOldMBarHeight;

        RectRgn(pOldGrayRgn, &pMenuRect);

        PaintBehind( frontWindow, pCopyGrayRgn);

        CalcVisBehind( frontWindow, pCopyGrayRgn);

        // draw the menubar in

        DrawMenuBar();

    }

    pMbarIsVisible = !pMbarIsVisible ;

    return ;

}

void FixGrayRgnAfterContextSwitch( void ) 

{

    WindowRef           frontWindow ;

    if((frontWindow = (WindowRef)FrontWindow()) == nil)

        return ;

    if(!pMbarIsVisible) {

        // store the grayrgn

        CopyRgn(GetGrayRgn(), pOldGrayRgn);

        // reset the menu bar height

        LMSetMBarHeight(0) ;

        // save the menu rect

        pMenuRect = qd.screenBits.bounds;

        pMenuRect.bottom = pOldMBarHeight;

        RectRgn(pMenuRgn, &pMenuRect);

        // and add this to the global grayrgn

        pCopyGrayRgn = GetGrayRgn() ;

        UnionRgn(pCopyGrayRgn, pMenuRgn, pCopyGrayRgn);

        LMSetGrayRgn( pCopyGrayRgn ) ;

        PaintBehind( frontWindow, pMenuRgn);

        CalcVisBehind( frontWindow, pMenuRgn);

    }

}