Quicktime File Format (2012-08-14).pdf

Some Useful Examples and ScenariosGetting the Name of a QuickTime VR Node//Get a pointer to the node header atom data.theErr = QTGetAtomDataPtr(theNodeInfo, theNodeHeaderAtom,nil,(Ptr*)&theNodeHeader);//See if there is a name atom.if (!theErr && theNodeHeader->nameAtomID != 0) {QTAtom theNameAtom;theNameAtom = QTFindChildByID(theNodeInfo, kParentAtomIsContainer,nil);kQTVRStringAtomType, theNodeHeader->nameAtomID,if (theNameAtom != 0) {VRStringAtomPtr theStringAtomPtr;//Get a pointer to the name atom data; copy it intotheErr = QTGetAtomDataPtr(theNodeInfo, theNameAtom,the string.nil,*)&theStringAtomPtr);(Ptrif (!theErr) {short theLen = theStringAtomPtr->stringLength;if (theLen > 255)theLen = 255;BlockMove(theStringAtomPtr->string, &theStringPtr[1],theLen);theStringPtr[0] = theLen;}}}QTUnlockContainer(theNodeInfo);}QTDisposeAtomContainer(theNodeInfo);return(theErr);}The MyGetNodeName function defined in Listing 6-14 (page 361) retrieves the node information atom container(by calling QTVRGetNodeInfo) and then looks inside that container for the node header atom with atom ID1. If it finds one, it locks the container and then gets a pointer to the node header atom data. The desiredinformation, the node name, is contained in the string atom whose atom ID is specified by the nameAtomID2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.362