The current version of HVCC (0.9) does not appear to render the trig input type correctly when generating DPF or Javascript user interfaces, and appears to treat them as a float (e.g. if defined as |r <name> @hvparam 0 1 0 trig| the UI will be a slider from 0 to 1). Suggest following up with Wasted-Audio or checking if a future release of HVCC addresses the issue.