示例#1
0
        /// <summary>
        /// Walk the tree to determine the absolute start and end times of all the elements.
        /// the reference times passed in are absolute times, the result of calling this is to set the local start time
        /// and end time to absolute times between these two reference times, based on the begin, end and dur attributes
        /// and to recursively set all of the children.
        /// </summary>
        public void ComputeTimeIntervals(TimeContainer context, TimeCode referenceStart, TimeCode referenceEnd)
        {
            m_startTime = new TimeCode(0d, TimeExpression.CurrentSmpteFrameRate);
            m_endTime   = new TimeCode(0d, TimeExpression.CurrentSmpteFrameRate);

            // compute the beginning of my interval.
            TimeCode begin = (Timing.ContainsKey("begin")) ? (TimeCode)Timing["begin"] : new TimeCode(0, TimeExpression.CurrentSmpteFrameRate);

            m_startTime = referenceStart + begin;

            TimeCode referenceDur, dur, end;

            // compute the simple duration of the interval ,
            // par children have indefinite default duration, seq children have zero default duration.
            // (we dont support indefinite here but  truncate to the outer container)
            // does end work here?  surely it truncates the active duration,
            if (!Timing.ContainsKey("dur") && !Timing.ContainsKey("end") && context == TimeContainer.Seq)
            {
                referenceDur = new TimeCode(0, TimeExpression.CurrentSmpteFrameRate);
            }
            else
            {
                if (m_startTime < referenceEnd)
                {
                    referenceDur = referenceEnd - m_startTime;
                }
                else
                {
                    referenceDur = new TimeCode(0, TimeExpression.CurrentSmpteFrameRate);
                }
            }

            bool containsDur = false;

            if (Timing.ContainsKey("dur"))
            {
                containsDur = true;
                dur         = (TimeCode)Timing["dur"];
                if (dur > referenceDur)
                {
                    dur = referenceDur;
                }
            }
            else
            {
                dur = referenceDur;
            }

            m_endTime = m_startTime + dur;

            // end can truncate the simple duration.
            TimeCode offsetEnd = new TimeCode(0, TimeExpression.CurrentSmpteFrameRate);

            offsetEnd += referenceStart;

            if (Timing.ContainsKey("end"))
            {
                end = referenceStart + ((TimeCode)Timing["end"]);
            }
            else
            {
                // Original code:
                //
                // end = referenceEnd;
                //
                // NOTE: This logic was changed from original TimedText library to properly handle
                //       Sequential time containers when the duration is indefinite.
                if (context == TimeContainer.Par)
                {
                    end = referenceEnd;
                }
                else
                {
                    end = m_startTime + referenceDur;
                }
            }
            //end = (Timing.ContainsKey("end")) ? (m_startTime.Add((TimeSpan)Timing["end"])) : referenceEnd;
            if (!containsDur)
            {
                m_endTime = end;
            }
            else
            {
                m_endTime = (end < m_endTime) ? end : m_endTime;
            }

            if (TimeSemantics == TimeContainer.Par)
            {
                foreach (TimeTree <TChildren, TAttribute> child in m_children)
                {
                    child.ComputeTimeIntervals(TimeSemantics, m_startTime, m_endTime);
                }
            }
            else
            {
                TimeCode s = m_startTime;
                foreach (TimeTree <TChildren, TAttribute> child in m_children)
                {
                    child.ComputeTimeIntervals(TimeSemantics, s, m_endTime);
                    s = child.m_endTime;
                }
            }
        }