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livetrax/share/scripts/stop_at_marker.lua

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ardour {
["type"] = "session",
name = "Stop at Marker",
license = "MIT",
author = "Ardour Lua Task Force",
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description = [[An example session script which stops the transport on every location marker when rolling forward.]]
}
function factory ()
return function (n_samples)
if (not Session:transport_rolling ()) then
-- not rolling, nothing to do.
return
end
local pos = Session:transport_sample () -- current playhead position
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local loc = Session:locations () -- all marker locations
-- find first marker after the current playhead position, ignore loop + punch ranges
-- (this only works when rolling forward, to extend this example see
-- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:Locations )
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--
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local m = loc:first_mark_after (pos, false)
if (m == -1) then
-- no marker was found
return
end
-- due to `first_mark_after(pos)` "m" is always > "pos":
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-- assert(pos < m)
--
-- This callback happens from within the process callback:
--
-- this cycle's end = next cycle start = pos + n_samples.
--
-- Note that if "m" is exactly at cycle's end, that marker
-- will be at "pos" in the next cycle. Since we ask for
-- "first_mark_after pos", the marker would not be found.
--
-- So even though "pos + n_samples" is barely reached,
-- we need to stop at "m" in the cycle that crosses or ends at "m".
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if (pos + n_samples >= m) then
-- asking to locate to "m" ensures that playback continues at "m"
-- and the same marker will not be taken into account.
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Session:request_locate (m, ARDOUR.LocateTransportDisposition.MustStop, ARDOUR.TransportRequestSource.TRS_Engine)
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end
end
end