// Offscreen.c

//

// Original version by Jon Lansdell and Nigel Humphreys.

// 3.1 updates by Greg Sutton.

// ©Apple Computer Inc 1996, all rights reserved.

#include "Offscreen.h"

#ifndef __QUICKDRAW__

    #include <Quickdraw.h>

#endif

#ifndef __QDOFFSCREEN__

    #include <QDOffscreen.h>

#endif

#ifndef __MEMORY__

    #include <Memory.h>

#endif

tWindowOffscreen* DrawOffscreen ( WindowRef theWindow )

{

    tWindowOffscreen*   theOffscreen;

    GWorldPtr           theWorld;

    Rect                globalRect;

    theOffscreen = (tWindowOffscreen*) NewPtr ( sizeof ( tWindowOffscreen ) );

    if ( theOffscreen == 0L )

        return 0L;

    SetPort ( theWindow );

    GetGWorld ( &theOffscreen->windowPort, &theOffscreen->windowDevice );

    globalRect = theWindow->portRect;

    LocalToGlobal ( (Point*) &globalRect.top );

    LocalToGlobal ( (Point*) &globalRect.bottom );

    if ( NewGWorld ( &theWorld, 0, &globalRect, 0L, 0L, 0) == noErr )

    {

        SetGWorld ( theWorld, 0L );

        if ( !LockPixels ( theWorld->portPixMap ) )

        {

            DisposeOffscreen ( theOffscreen );

            return 0L;

        }

        CopyBits ( &theWindow->portBits, &((GrafPtr) theWorld)->portBits,

                    &theWindow->portRect, &theWorld->portRect, srcCopy, 0L );

        theOffscreen->offscreenWorld = theWorld;

        return theOffscreen;

    }

    DisposePtr ( (Ptr) theOffscreen );

    return 0L;

}

tWindowOffscreen* DrawOnscreen ( tWindowOffscreen* theOffscreen )

{

    if ( theOffscreen )

    {

        SetGWorld ( theOffscreen->windowPort, theOffscreen->windowDevice );

        CopyBits ( &((GrafPtr) theOffscreen->offscreenWorld)->portBits,

                        (BitMap*) &(theOffscreen->windowPort)->portPixMap,

                        &theOffscreen->offscreenWorld->portRect,

                        &theOffscreen->windowPort->portRect,

                        srcCopy, 0L );

        UnlockPixels ( theOffscreen->offscreenWorld->portPixMap );

        DisposeOffscreen ( theOffscreen );

    }

    return nil;

}

tWindowOffscreen* DisposeOffscreen ( tWindowOffscreen* theOffscreen )

{

    DisposeGWorld ( theOffscreen->offscreenWorld );

    DisposePtr ( (Ptr) theOffscreen );

    return nil;

}