ACE Inline Correlation Meter (needs work, debug builds only)

share/scripts/_correlation_meter.lua

@@ -0,0 +1,85 @@
+ardour {
+	["type"]    = "dsp",
+	name        = "ACE Inline Correlation Meter",
+	category    = "Visualization",
+	license     = "MIT",
+	author      = "Ardour Community",
+	description = [[Mixer strip inline stereo correlation meter]]
+}
+
+function dsp_ioconfig ()
+	return { [1] = { audio_in = 2, audio_out = 2}, }
+end
+
+function dsp_params ()
+	return {}
+end
+
+function dsp_init (rate)
+	stdcorr = ARDOUR.DSP.StereoCorrelation (rate, 2000, 0.3)
+	samplerate = rate
+	dpy_hz = rate / 25
+	dpy_wr = 0
+end
+
+function dsp_configure (ins, outs)
+	self:shmem ():allocate (1)
+	self:shmem ():clear()
+end
+
+function dsp_run (ins, outs, n_samples)
+
+	stdcorr:process (ins[1], ins[2], n_samples)
+	self:shmem ():to_float (0):array()[1] = stdcorr:read ()
+
+	-- emit QueueDraw every FPS
+	dpy_wr = dpy_wr + n_samples
+	if (dpy_wr > dpy_hz) then
+		dpy_wr = dpy_wr % dpy_hz;
+		self:queue_draw ()
+	end
+
+end
+
+-------------------------------------------------------------------------------
+--- inline display
+
+function render_inline (ctx, w, max_h)
+	local shmem = self:shmem () -- get shared memory region
+	local corr = self:shmem ():to_float (0):array()[1]
+
+	local h = 14
+
+	if (h > max_h) then
+		h = max_h
+	end
+
+	-- clear background
+	ctx:rectangle (0, 0, w, h)
+	ctx:set_source_rgba (.2, .2, .2, 1.0)
+	ctx:fill ()
+
+	-- TODO add gridlines
+
+	-- draw signal
+	if (corr > 0.5) then
+		ctx:set_source_rgba (.1, .9, .1, 1.0)
+	elseif corr > -0.5 then
+		ctx:set_source_rgba (.7, .7, .1, 1.0)
+	else
+		ctx:set_source_rgba (.9, .1, .1, 1.0)
+	end
+
+	local w2 = 0.5 * w
+	local x  = 0.5 * (corr * (w - 4))
+
+	if corr > 0 then
+		ctx:rectangle (w2,     1, 1 + x, 12)
+	else
+		ctx:rectangle (w2 + x, 1, 1 - x, 12)
+	end
+
+	ctx:fill ()
+
+	return {w, h}
+end