add lua DSP transfer function calculation

[ardour.git] / libs / ardour / ardour / dsp_filter.h

diff --git a/libs/ardour/ardour/dsp_filter.h b/libs/ardour/ardour/dsp_filter.h
index ddf61075cd642f4cea726587f17fcbf153c8dc1e..1ffccd331982e73c2f929060967ddb934c7dd723 100644 (file)
--- a/libs/ardour/ardour/dsp_filter.h
+++ b/libs/ardour/ardour/dsp_filter.h
@@ -228,6 +228,13 @@ namespace ARDOUR { namespace DSP {
                         * @param gain filter gain
                         */
                        void compute (Type t, double freq, double Q, double gain);
+
+                       /** filter transfer function (for spectrum visualization)
+                        * @param freq frequency
+                        * @return gain at given frequency in dB
+                        */
+                       float dB_at_freq (float freq) const;
+
                        /** reset filter state */
                        void reset () { _z1 = _z2 = 0.0; }
                private: