Current capture, or null when none was taken since arming.
true for single-shot mode, false for normal mode.
Trigger settings.
Live buffer, sorted by time, already including the batch.
Index in buffer of the batch's first point.
The buffer was emptied before this batch.
Points just appended.
The capture to show: capture itself when unchanged, a new object when it
changed, or null when there is none.
Advances one channel's trigger after a new batch was appended to its live buffer.
An open capture takes the batch's samples up to its window end; if the buffer was reset (the timeline jumped back) it is closed as it is. A capture is held while it is collecting, and in single-shot mode until the user re-arms. Otherwise the new samples are searched for a crossing after the end of the previous capture (with the full pre-trigger window buffered), and a crossing starts a new capture from the buffer. In normal mode a capture that completes within the same batch is followed by a search for the next crossing, so the last one found is returned.