Programming With QuickTime Sprites

Setting Up the Sprite Track's Properities

Listing 2-17 shows a code fragment that sets the sprite track's background color, idle event frequency and its hasActions properties.

Listing 17 Setting the background color, idle event frequency and hasActions properties of the sprite track



 
// set the sprite track properties

    {

        QTAtomContainer     myTrackProperties;

        RGBColor            myBackgroundColor;

        

        // add a background color to the sprite track

        myBackgroundColor.red = EndianU16_NtoB(0x8000);

        myBackgroundColor.green = EndianU16_NtoB(0);

        myBackgroundColor.blue = EndianU16_NtoB(0xffff);

        

        QTNewAtomContainer(&myTrackProperties);

        QTInsertChild(myTrackProperties, 0, 

                        kSpriteTrackPropertyBackgroundColor, 1, 1, 

                        sizeof(RGBColor), &myBackgroundColor, NULL);



// tell the movie controller that this sprite track has actions

        hasActions = true;

        QTInsertChild(myTrackProperties, 0, 

                        kSpriteTrackPropertyHasActions, 1, 1, 

                    sizeof(hasActions), &hasActions, NULL);

    

        // tell the sprite track to generate QTIdleEvents

        myFrequency = EndianU32_NtoB(60);

        QTInsertChild(myTrackProperties, 0, 

                        kSpriteTrackPropertyQTIdleEventsFrequency, 1, 1, 

                            sizeof(myFrequency), &myFrequency, NULL);

        myErr = SetMediaPropertyAtom(myMedia, myTrackProperties);

        if (myErr != noErr)

            goto bail;



        QTDisposeAtomContainer(myTrackProperties);

    }