QuickTime 4 Reference

CreateSamplePathTweenContainer Utility

Listing 10 shows the CreateSamplePathTweenContainer routine, which creates the path tween containers used in Listing 11 through Listing 19 .

Listing 10 Utility routine CreateSamplePathTweenContainer



 
OSErr CreateSamplePathTweenContainer( QTAtomContainer container, 

    OSType tweenerType, long whichSamplePath, Boolean returnDelta,

    TimeValue duration, Fixed initialRotation, QTAtom *newTweenAtom )

{

    OSErr           err = noErr;

    TimeValue       offset;

    Handle          thePathData = nil;

    QTAtom          tweenAtom;

    

    err = QTRemoveChildren( container, kParentAtomIsContainer );

    if ( err ) goto bail;



    offset = 0;

    err = AddTweenAtom( container, kParentAtomIsContainer, 1,

                        tweenerType, offset, duration, 0, 0, nil,

                        &tweenAtom );

    if ( err ) goto bail;

                    

    thePathData = CreateSampleVectorData( whichSamplePath );

    if ( thePathData == nil ) { err = memFullErr; goto bail; }

    

    HLock( thePathData );

    

    err = AddDataAtom( container, tweenAtom, 1, 

                        GetHandleSize( thePathData ), *thePathData, 

                        nil, 0, nil );

    if ( err ) goto bail;



    if ( returnDelta ) {

        err = AddPathTweenFlags( container, tweenAtom, 

                                    kTweenReturnDelta );

    }



    if ( initialRotation )

        QTInsertChild( container, tweenAtom, kInitialRotationAtom, 

                1, 1, sizeof(initialRotation), &initialRotation, nil ); 



bail:

    if ( thePathData ) DisposeHandle( thePathData );

    if ( newTweenAtom ) *newTweenAtom = tweenAtom;

    return err;