Add example scope plugin from Robin Gareus.

7 files changed, 1381 insertions, 0 deletions

diff --git a/plugins/eg05-scope.lv2/README.txt b/plugins/eg05-scope.lv2/README.txt
new file mode 100644
index 0000000..ec3578b
--- /dev/null
+++ b/plugins/eg05-scope.lv2/README.txt
@@ -0,0 +1,30 @@
+== Simple Oscilloscope ==
+
+This plugin displays the wave-form of an incoming audio-signal using a simple
+GTK+Cairo GUI.
+
+This plugin illustrates:
+
+- UI <==> Plugin communication via LV2 atom events
+- LV2 Atom vector usage and resize-port extension
+- Save/Restore UI state by communicating state to backend
+- Cairo drawing and partial exposure
+
+This plugin intends to outline the basics for building visualization plugins
+that rely on Atom communication.  The UI looks likean oscilloscope, but is not a real oscilloscope implementation:
+
+- There is no display synchronisation, results will depend on LV2 host.
+- It displays raw audio samples, which a proper scope must not do.
+- The display itself just connects min/max line segments.
+- No triggering or synchronization.
+- No labels, no scale, no calibration, no markers, no numeric readout, etc.
+
+Addressing these issues is beyond the scope of this example.
+
+Please see http://lac.linuxaudio.org/2013/papers/36.pdf for scope design,
+https://wiki.xiph.org/Videos/Digital_Show_and_Tell for background information,
+and http://lists.lv2plug.in/pipermail/devel-lv2plug.in/2013-November/000545.html
+for general LV2 related conceptual criticism regarding real-time visualizations.
+
+A proper oscilloscope based on this example can be found at
+https://github.com/x42/sisco.lv2
diff --git a/plugins/eg05-scope.lv2/examploscope.c b/plugins/eg05-scope.lv2/examploscope.c
new file mode 100644
index 0000000..13281ab
--- /dev/null
+++ b/plugins/eg05-scope.lv2/examploscope.c
@@ -0,0 +1,404 @@
+/*
+  Copyright 2013 Robin Gareus <robin@gareus.org>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+#include "lv2/lv2plug.in/ns/ext/log/log.h"
+#include "lv2/lv2plug.in/ns/ext/log/logger.h"
+#include "lv2/lv2plug.in/ns/ext/state/state.h"
+#include "lv2/lv2plug.in/ns/lv2core/lv2.h"
+
+#include "./uris.h"
+
+/** Private plugin instance structure. */
+typedef struct {
+	// Port buffers
+	float*                   input[2];
+	float*                   output[2];
+	const LV2_Atom_Sequence* control;
+	LV2_Atom_Sequence*       notify;
+
+	// Atom forge and URI mapping
+	LV2_URID_Map*        map;
+	ScoLV2URIs           uris;
+	LV2_Atom_Forge       forge;
+	LV2_Atom_Forge_Frame frame;
+
+	// Log feature and convenience API
+	LV2_Log_Log*   log;
+	LV2_Log_Logger logger;
+
+	// Instantiation settings
+	uint32_t n_channels;
+	double   rate;
+
+	/* The state of the UI is stored here, so that the GUI can be displayed and
+	   closed without losing the current settings.  It is communicated to the
+	   UI using atom messages.
+	*/
+	bool     ui_active;
+	bool     send_settings_to_ui;
+	float    ui_amp;
+	uint32_t ui_spp;
+} EgScope;
+
+/** Port indices. */
+typedef enum {
+	SCO_CONTROL = 0,
+	SCO_NOTIFY  = 1,
+	SCO_INPUT0  = 2,
+	SCO_OUTPUT0 = 3,
+	SCO_INPUT1  = 4,
+	SCO_OUTPUT1 = 5,
+} PortIndex;
+
+/** Create plugin instance. */
+static LV2_Handle
+instantiate(const LV2_Descriptor*     descriptor,
+            double                    rate,
+            const char*               bundle_path,
+            const LV2_Feature* const* features)
+{
+	(void)descriptor;   // Unused variable
+	(void)bundle_path;  // Unused variable
+
+	// Allocate and initialise instance structure.
+	EgScope* self = (EgScope*)calloc(1, sizeof(EgScope));
+	if (!self) {
+		return NULL;
+	}
+
+	// Get host features
+	for (int i = 0; features[i]; ++i) {
+		if (!strcmp(features[i]->URI, LV2_URID__map)) {
+			self->map = (LV2_URID_Map*)features[i]->data;
+		} else if (!strcmp(features[i]->URI, LV2_LOG__log)) {
+			self->log = (LV2_Log_Log*)features[i]->data;
+		}
+	}
+
+	if (!self->map) {
+		fprintf(stderr, "EgScope.lv2 error: Host does not support urid:map\n");
+		free(self);
+		return NULL;
+	}
+
+	// Decide which variant to use depending on the plugin URI
+	if (!strcmp(descriptor->URI, SCO_URI "#Stereo")) {
+		self->n_channels = 2;
+	} else if (!strcmp(descriptor->URI, SCO_URI "#Mono")) {
+		self->n_channels = 1;
+	} else {
+		free(self);
+		return NULL;
+	}
+
+	// Initialise local variables
+	self->ui_active           = false;
+	self->send_settings_to_ui = false;
+	self->rate                = rate;
+
+	// Set default UI settings
+	self->ui_spp = 50;
+	self->ui_amp = 1.0;
+
+	// Map URIs and initialise forge/logger
+	map_sco_uris(self->map, &self->uris);
+	lv2_atom_forge_init(&self->forge, self->map);
+	lv2_log_logger_init(&self->logger, self->map, self->log);
+
+	return (LV2_Handle)self;
+}
+
+/** Connect a port to a buffer. */
+static void
+connect_port(LV2_Handle handle,
+             uint32_t   port,
+             void*      data)
+{
+	EgScope* self = (EgScope*)handle;
+
+	switch ((PortIndex)port) {
+	case SCO_CONTROL:
+		self->control = (const LV2_Atom_Sequence*)data;
+		break;
+	case SCO_NOTIFY:
+		self->notify = (LV2_Atom_Sequence*)data;
+		break;
+	case SCO_INPUT0:
+		self->input[0] = (float*)data;
+		break;
+	case SCO_OUTPUT0:
+		self->output[0] = (float*)data;
+		break;
+	case SCO_INPUT1:
+		self->input[1] = (float*)data;
+		break;
+	case SCO_OUTPUT1:
+		self->output[1] = (float*)data;
+		break;
+	}
+}
+
+/**
+   Forge vector of raw data.
+
+   @param forge Forge to use.
+   @param uris Mapped URI identifiers.
+   @param channel Channel ID to transmit.
+   @param n_samples Number of audio samples to transmit.
+   @param data Actual audio data.
+*/
+static void
+tx_rawaudio(LV2_Atom_Forge* forge,
+            ScoLV2URIs*     uris,
+            const int32_t   channel,
+            const size_t    n_samples,
+            void*           data)
+{
+	LV2_Atom_Forge_Frame frame;
+
+	// Forge container object of type 'rawaudio'
+	lv2_atom_forge_frame_time(forge, 0);
+	lv2_atom_forge_blank(forge, &frame, 1, uris->RawAudio);
+
+	// Add integer attribute 'channelid'
+	lv2_atom_forge_property_head(forge, uris->channelID, 0);
+	lv2_atom_forge_int(forge, channel);
+
+	// Add vector of floats raw 'audiodata'
+	lv2_atom_forge_property_head(forge, uris->audioData, 0);
+	lv2_atom_forge_vector(
+		forge, sizeof(float), uris->atom_Float, n_samples, data);
+
+	// Close off atom-object
+	lv2_atom_forge_pop(forge, &frame);
+}
+
+/** Process a block of audio */
+static void
+run(LV2_Handle handle, uint32_t n_samples)
+{
+	EgScope* self = (EgScope*)handle;
+
+	/* Ensure notify port buffer is large enough to hold all audio-samples and
+	   configuration settings.  A minimum size was requested in the .ttl file,
+	   but check here just to be sure.
+
+	   TODO: Explain these magic numbers.
+	*/
+	const size_t   size  = (sizeof(float) * n_samples + 64) * self->n_channels;
+	const uint32_t space = self->notify->atom.size;
+	if (space < size + 128) {
+		/* Insufficient space, report error and do nothing.  Note that a
+		   real-time production plugin mustn't call log functions in run(), but
+		   this can be useful for debugging and example purposes.
+		*/
+		lv2_log_error(&self->logger, "Buffer size is insufficient\n");
+		return;
+	}
+
+	// Prepare forge buffer and initialize atom-sequence
+	lv2_atom_forge_set_buffer(&self->forge, (uint8_t*)self->notify, space);
+	lv2_atom_forge_sequence_head(&self->forge, &self->frame, 0);
+
+	/* Send settings to UI
+
+	   The plugin can continue to run while the UI is closed and re-opened.
+	   The state and settings of the UI are kept here and transmitted to the UI
+	   every time it asks for them or if the user initializes a 'load preset'.
+	*/
+	if (self->send_settings_to_ui && self->ui_active) {
+		self->send_settings_to_ui = false;
+		// Forge container object of type 'ui_state'
+		LV2_Atom_Forge_Frame frame;
+		lv2_atom_forge_frame_time(&self->forge, 0);
+		lv2_atom_forge_blank(&self->forge, &frame, 1, self->uris.ui_State);
+
+		// Add UI state as properties
+		lv2_atom_forge_property_head(&self->forge, self->uris.ui_spp, 0);
+		lv2_atom_forge_int(&self->forge, self->ui_spp);
+		lv2_atom_forge_property_head(&self->forge, self->uris.ui_amp, 0);
+		lv2_atom_forge_float(&self->forge, self->ui_amp);
+		lv2_atom_forge_property_head(&self->forge, self->uris.param_sampleRate, 0);
+		lv2_atom_forge_float(&self->forge, self->rate);
+		lv2_atom_forge_pop(&self->forge, &frame);
+	}
+
+	// Process incoming events from GUI
+	if (self->control) {
+		LV2_Atom_Event* ev = lv2_atom_sequence_begin(&(self->control)->body);
+		// For each incoming message...
+		while (!lv2_atom_sequence_is_end(
+			       &self->control->body, self->control->atom.size, ev)) {
+			// If the event is an atom:Blank object
+			if (ev->body.type == self->uris.atom_Blank) {
+				const LV2_Atom_Object* obj = (LV2_Atom_Object*)&ev->body;
+				if (obj->body.otype == self->uris.ui_On) {
+					// If the object is a ui-on, the UI was activated
+					self->ui_active           = true;
+					self->send_settings_to_ui = true;
+				} else if (obj->body.otype == self->uris.ui_Off) {
+					// If the object is a ui-off, the UI was closed
+					self->ui_active = false;
+				} else if (obj->body.otype == self->uris.ui_State) {
+					// If the object is a ui-state, it's the current UI settings
+					const LV2_Atom* spp = NULL;
+					const LV2_Atom* amp = NULL;
+					lv2_atom_object_get(obj, self->uris.ui_spp, &spp,
+					                    self->uris.ui_amp, &amp,
+					                    0);
+					if (spp) {
+						self->ui_spp = ((LV2_Atom_Int*)spp)->body;
+					}
+					if (amp) {
+						self->ui_amp = ((LV2_Atom_Float*)amp)->body;
+					}
+				}
+			}
+			ev = lv2_atom_sequence_next(ev);
+		}
+	}
+
+	// Process audio data
+	for (uint32_t c = 0; c < self->n_channels; ++c) {
+		if (self->ui_active) {
+			// If UI is active, send raw audio data to UI
+			tx_rawaudio(&self->forge, &self->uris, c, n_samples, self->input[c]);
+		}
+		// If not processing audio in-place, forward audio
+		if (self->input[c] != self->output[c]) {
+			memcpy(self->output[c], self->input[c], sizeof(float) * n_samples);
+		}
+	}
+
+	// Close off sequence
+	lv2_atom_forge_pop(&self->forge, &self->frame);
+}
+
+static void
+cleanup(LV2_Handle handle)
+{
+	free(handle);
+}
+
+static LV2_State_Status
+state_save(LV2_Handle                instance,
+           LV2_State_Store_Function  store,
+           LV2_State_Handle          handle,
+           uint32_t                  flags,
+           const LV2_Feature* const* features)
+{
+	EgScope* self = (EgScope*)instance;
+	if (!self) {
+		return LV2_STATE_SUCCESS;
+	}
+
+	/* Store state values.  Note these values are POD, but not portable, since
+	   different machines may have a different integer endianness or floating
+	   point format.  However, since standard Atom types are used, a good host
+	   will be able to save them portably as text anyway. */
+
+	store(handle, self->uris.ui_spp,
+	      (void*)&self->ui_spp, sizeof(uint32_t),
+	      self->uris.atom_Int,
+	      LV2_STATE_IS_POD);
+
+	store(handle, self->uris.ui_amp,
+	      (void*)&self->ui_amp, sizeof(float),
+	      self->uris.atom_Float,
+	      LV2_STATE_IS_POD);
+
+	return LV2_STATE_SUCCESS;
+}
+
+static LV2_State_Status
+state_restore(LV2_Handle                  instance,
+              LV2_State_Retrieve_Function retrieve,
+              LV2_State_Handle            handle,
+              uint32_t                    flags,
+              const LV2_Feature* const*   features)
+{
+	EgScope* self = (EgScope*)instance;
+
+	size_t   size;
+	uint32_t type;
+	uint32_t valflags;
+
+	const void* spp = retrieve(
+		handle, self->uris.ui_spp, &size, &type, &valflags);
+	if (spp && size == sizeof(uint32_t) && type == self->uris.atom_Int) {
+		self->ui_spp              = *((uint32_t*)spp);
+		self->send_settings_to_ui = true;
+	}
+
+	const void* amp = retrieve(
+		handle, self->uris.ui_amp, &size, &type, &valflags);
+	if (amp && size == sizeof(float) && type == self->uris.atom_Float) {
+		self->ui_amp              = *((float*)amp);
+		self->send_settings_to_ui = true;
+	}
+
+	return LV2_STATE_SUCCESS;
+}
+
+static const void*
+extension_data(const char* uri)
+{
+	static const LV2_State_Interface state = { state_save, state_restore };
+	if (!strcmp(uri, LV2_STATE__interface)) {
+		return &state;
+	}
+	return NULL;
+}
+
+static const LV2_Descriptor descriptor_mono = {
+	SCO_URI "#Mono",
+	instantiate,
+	connect_port,
+	NULL,
+	run,
+	NULL,
+	cleanup,
+	extension_data
+};
+
+static const LV2_Descriptor descriptor_stereo = {
+	SCO_URI "#Stereo",
+	instantiate,
+	connect_port,
+	NULL,
+	run,
+	NULL,
+	cleanup,
+	extension_data
+};
+
+LV2_SYMBOL_EXPORT
+const LV2_Descriptor*
+lv2_descriptor(uint32_t index)
+{
+	switch (index) {
+	case 0:
+		return &descriptor_mono;
+	case 1:
+		return &descriptor_stereo;
+	default:
+		return NULL;
+	}
+}
diff --git a/plugins/eg05-scope.lv2/examploscope.ttl.in b/plugins/eg05-scope.lv2/examploscope.ttl.in
new file mode 100644
index 0000000..0b76962
--- /dev/null
+++ b/plugins/eg05-scope.lv2/examploscope.ttl.in
@@ -0,0 +1,130 @@
+@prefix atom:    <http://lv2plug.in/ns/ext/atom#> .
+@prefix bufsz:   <http://lv2plug.in/ns/ext/buf-size#> .
+@prefix doap:    <http://usefulinc.com/ns/doap#> .
+@prefix foaf:    <http://xmlns.com/foaf/0.1/> .
+@prefix lv2:     <http://lv2plug.in/ns/lv2core#> .
+@prefix rdfs:    <http://www.w3.org/2000/01/rdf-schema#> .
+@prefix ui:      <http://lv2plug.in/ns/extensions/ui#> .
+@prefix urid:    <http://lv2plug.in/ns/ext/urid#> .
+@prefix rsz:     <http://lv2plug.in/ns/ext/resize-port#> .
+@prefix state:   <http://lv2plug.in/ns/ext/state#> .
+@prefix egscope: <http://lv2plug.in/plugins/eg-scope#> .
+
+<http://gareus.org/rgareus#me>
+	a foaf:Person ;
+	foaf:name "Robin Gareus" ;
+	foaf:mbox <mailto:robin@gareus.org> ;
+	foaf:homepage <http://gareus.org/> .
+
+<http://lv2plug.in/plugins/eg-scope>
+	a doap:Project ;
+	doap:maintainer <http://gareus.org/rgareus#me> ;
+	doap:name "Example Scope" .
+
+egscope:Mono
+	a lv2:Plugin, lv2:AnalyserPlugin ;
+	doap:name "Example Scope (Mono)" ;
+	lv2:project <http://lv2plug.in/plugins/eg-scope> ;
+	doap:license <http://usefulinc.com/doap/licenses/gpl> ;
+	lv2:requiredFeature urid:map ;
+	lv2:optionalFeature lv2:hardRTCapable ;
+	lv2:extensionData state:interface ;
+	ui:ui egscope:ui ;
+	lv2:port [
+		a atom:AtomPort ,
+			lv2:InputPort ;
+		atom:bufferType atom:Sequence ;
+		lv2:designation lv2:control ;
+		lv2:index 0 ;
+		lv2:symbol "control" ;
+		lv2:name "Control"
+	] , [
+		a atom:AtomPort ,
+			lv2:OutputPort ;
+		atom:bufferType atom:Sequence ;
+		lv2:designation lv2:control ;
+		lv2:index 1 ;
+		lv2:symbol "notify" ;
+		lv2:name "Notify" ;
+		# 8192 * sizeof(float) + LV2-Atoms
+		rsz:minimumSize 32832;
+	] , [
+		a lv2:AudioPort ,
+			lv2:InputPort ;
+		lv2:index 2 ;
+		lv2:symbol "in" ;
+		lv2:name "In"
+	] , [
+		a lv2:AudioPort ,
+			lv2:OutputPort ;
+		lv2:index 3 ;
+		lv2:symbol "out" ;
+		lv2:name "Out"
+	] .
+
+
+egscope:Stereo
+	a lv2:Plugin, lv2:AnalyserPlugin ;
+	doap:name "Example Scope (Stereo)" ;
+	lv2:project <http://lv2plug.in/plugins/eg-scope> ;
+	doap:license <http://usefulinc.com/doap/licenses/gpl> ;
+	lv2:requiredFeature urid:map ;
+	lv2:optionalFeature lv2:hardRTCapable ;
+	lv2:extensionData state:interface ;
+	ui:ui egscope:ui ;
+	lv2:port [
+		a atom:AtomPort ,
+			lv2:InputPort ;
+		atom:bufferType atom:Sequence ;
+		lv2:designation lv2:control ;
+		lv2:index 0 ;
+		lv2:symbol "control" ;
+		lv2:name "Control"
+	] , [
+		a atom:AtomPort ,
+			lv2:OutputPort ;
+		atom:bufferType atom:Sequence ;
+		lv2:designation lv2:control ;
+		lv2:index 1 ;
+		lv2:symbol "notify" ;
+		lv2:name "Notify" ;
+		rsz:minimumSize 65664;
+	] , [
+		a lv2:AudioPort ,
+			lv2:InputPort ;
+		lv2:index 2 ;
+		lv2:symbol "in0" ;
+		lv2:name "InL"
+	] , [
+		a lv2:AudioPort ,
+			lv2:OutputPort ;
+		lv2:index 3 ;
+		lv2:symbol "out0" ;
+		lv2:name "OutL"
+	] , [
+		a lv2:AudioPort ,
+			lv2:InputPort ;
+		lv2:index 4 ;
+		lv2:symbol "in1" ;
+		lv2:name "InR"
+	] , [
+		a lv2:AudioPort ,
+			lv2:OutputPort ;
+		lv2:index 5 ;
+		lv2:symbol "out1" ;
+		lv2:name "OutR"
+	] .
+
+
+egscope:ui
+	a ui:GtkUI ;
+	lv2:requiredFeature urid:map ;
+	ui:portNotification [
+		ui:plugin egscope:Mono ;
+		lv2:symbol "notify" ;
+		ui:notifyType atom:Blank
+	] , [
+		ui:plugin egscope:Stereo ;
+		lv2:symbol "notify" ;
+		ui:notifyType atom:Blank
+	] .
diff --git a/plugins/eg05-scope.lv2/examploscope_ui.c b/plugins/eg05-scope.lv2/examploscope_ui.c
new file mode 100644
index 0000000..ffbe573
--- /dev/null
+++ b/plugins/eg05-scope.lv2/examploscope_ui.c
@@ -0,0 +1,653 @@
+/*
+  Copyright 2013 Robin Gareus <robin@gareus.org>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <cairo.h>
+#include <gtk/gtk.h>
+
+#include "lv2/lv2plug.in/ns/extensions/ui/ui.h"
+#include "./uris.h"
+
+// Drawing area size
+#define DAWIDTH  (640)
+#define DAHEIGHT (200)
+
+/**
+   Max continuous points on path.  Many short-path segments are
+   expensive|inefficient long paths are not supported by all surfaces (usually
+   its a miter - not point - limit, depending on used cairo backend)
+*/
+#define MAX_CAIRO_PATH (128)
+
+/**
+   Representation of the raw audio-data for display (min | max) values for a
+   given 'index' position.
+*/
+typedef struct {
+	float data_min[DAWIDTH];
+	float data_max[DAWIDTH];
+
+	uint32_t idx;
+	uint32_t sub;
+} ScoChan;
+
+typedef struct {
+	LV2_Atom_Forge forge;
+	LV2_URID_Map*  map;
+	ScoLV2URIs     uris;
+
+	LV2UI_Write_Function write;
+	LV2UI_Controller     controller;
+
+	GtkWidget*     hbox;
+	GtkWidget*     vbox;
+	GtkWidget*     sep[2];
+	GtkWidget*     darea;
+	GtkWidget*     btn_pause;
+	GtkWidget*     lbl_speed;
+	GtkWidget*     lbl_amp;
+	GtkWidget*     spb_speed;
+	GtkWidget*     spb_amp;
+	GtkAdjustment* spb_speed_adj;
+	GtkAdjustment* spb_amp_adj;
+
+	ScoChan  chn[2];
+	uint32_t stride;
+	uint32_t n_channels;
+	bool     paused;
+	float    rate;
+} EgScopeUI;
+
+
+/** Send current UI settings to backend. */
+static void
+send_ui_state(LV2UI_Handle handle)
+{
+	EgScopeUI*  ui   = (EgScopeUI*)handle;
+	const float gain = gtk_spin_button_get_value(GTK_SPIN_BUTTON(ui->spb_amp));
+
+	// Use local buffer on the stack to build atom
+	uint8_t obj_buf[1024];
+	lv2_atom_forge_set_buffer(&ui->forge, obj_buf, sizeof(obj_buf));
+
+	// Event body is a ui_state object
+	LV2_Atom_Forge_Frame frame;
+	LV2_Atom*            msg = (LV2_Atom*)lv2_atom_forge_blank(
+		&ui->forge, &frame, 1, ui->uris.ui_State);
+
+	// msg[samples-per-pixel] = integer
+	lv2_atom_forge_property_head(&ui->forge, ui->uris.ui_spp, 0);
+	lv2_atom_forge_int(&ui->forge, ui->stride);
+	// msg[amplitude] = float
+	lv2_atom_forge_property_head(&ui->forge, ui->uris.ui_amp, 0);
+	lv2_atom_forge_float(&ui->forge, gain);
+	// Close off forged data
+	lv2_atom_forge_pop(&ui->forge, &frame);
+
+	// Send message to plugin port '0'
+	ui->write(ui->controller,
+	          0,
+	          lv2_atom_total_size(msg),
+	          ui->uris.atom_eventTransfer,
+	          msg);
+}
+
+/** Notify backend that UI is closed. */
+static void
+send_ui_disable(LV2UI_Handle handle)
+{
+	EgScopeUI* ui = (EgScopeUI*)handle;
+	send_ui_state(handle);
+
+	uint8_t obj_buf[64];
+	lv2_atom_forge_set_buffer(&ui->forge, obj_buf, sizeof(obj_buf));
+
+	LV2_Atom_Forge_Frame frame;
+	LV2_Atom*            msg = (LV2_Atom*)lv2_atom_forge_blank(
+		&ui->forge, &frame, 1, ui->uris.ui_Off);
+	lv2_atom_forge_pop(&ui->forge, &frame);
+	ui->write(ui->controller,
+	          0,
+	          lv2_atom_total_size(msg),
+	          ui->uris.atom_eventTransfer,
+	          msg);
+}
+
+/**
+   Notify backend that UI is active.
+
+   The plugin should send state and enable data transmission.
+*/
+static void
+send_ui_enable(LV2UI_Handle handle)
+{
+	EgScopeUI* ui = (EgScopeUI*)handle;
+
+	uint8_t obj_buf[64];
+	lv2_atom_forge_set_buffer(&ui->forge, obj_buf, sizeof(obj_buf));
+
+	LV2_Atom_Forge_Frame frame;
+	LV2_Atom*            msg = (LV2_Atom*)lv2_atom_forge_blank(
+		&ui->forge, &frame, 1, ui->uris.ui_On);
+	lv2_atom_forge_pop(&ui->forge, &frame);
+	ui->write(ui->controller,
+	          0,
+	          lv2_atom_total_size(msg),
+	          ui->uris.atom_eventTransfer,
+	          msg);
+}
+
+/** Gtk widget callback. */
+static gboolean
+on_cfg_changed(GtkWidget* widget, gpointer data)
+{
+	send_ui_state(data);
+	return TRUE;
+}
+
+/**
+   Gdk drawing area draw callback.
+
+   Called in Gtk's main thread and uses Cairo to draw the data.
+*/
+static gboolean
+on_expose_event(GtkWidget* widget, GdkEventExpose* ev, gpointer data)
+{
+	EgScopeUI*  ui   = (EgScopeUI*)data;
+	const float gain = gtk_spin_button_get_value(GTK_SPIN_BUTTON(ui->spb_amp));
+
+	// Get cairo type for the gtk window
+	cairo_t* cr;
+	cr = gdk_cairo_create(ui->darea->window);
+
+	// Limit cairo-drawing to exposed area
+	cairo_rectangle(cr, ev->area.x, ev->area.y, ev->area.width, ev->area.height);
+	cairo_clip(cr);
+
+	// Clear background
+	cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, 1.0);
+	cairo_rectangle(cr, 0, 0, DAWIDTH, DAHEIGHT * ui->n_channels);
+	cairo_fill(cr);
+
+	cairo_set_line_width(cr, 1.0);
+
+	const uint32_t start = ev->area.x;
+	const uint32_t end   = ev->area.x + ev->area.width;
+
+	assert(start < DAWIDTH);
+	assert(end <= DAWIDTH);
+	assert(start < end);
+
+	for (uint32_t c = 0; c < ui->n_channels; ++c) {
+		ScoChan* chn = &ui->chn[c];
+
+		/* Drawing area Y-position of given sample-value.
+		 * Note: cairo-pixel at 0 spans -0.5 .. +0.5, hence (DAHEIGHT / 2.0 -0.5)
+		 * also the cairo Y-axis points upwards (hence 'minus value')
+		 *
+		 * == (   DAHEIGHT * (CHN)        // channel offset
+		 *      + (DAHEIGHT / 2) - 0.5    // vertical center -- '0'
+		 *      - (DAHEIGHT / 2) * (VAL) * (GAIN)
+		 *    )
+		 */
+		const float chn_y_offset = DAHEIGHT * c + DAHEIGHT * 0.5f - 0.5f;
+		const float chn_y_scale  = DAHEIGHT * 0.5f * gain;
+
+#define CYPOS(VAL) (chn_y_offset - (VAL) * chn_y_scale)
+
+		cairo_save(cr);
+
+		/* Restrict drawing to current channel area, don't bleed drawing into
+		   neighboring channels. */
+		cairo_rectangle(cr, 0, DAHEIGHT * c, DAWIDTH, DAHEIGHT);
+		cairo_clip(cr);
+
+		// Set color of wave-form
+		cairo_set_source_rgba(cr, 0.0, 1.0, 0.0, 1.0);
+
+		/* This is a somewhat 'smart' mechanism to plot audio data using
+		   alternating up/down line-directions.  It works well for both cases:
+		   1 pixel <= 1 sample and 1 pixel represents more than 1 sample, but
+		   is not ideal for either. */
+		if (start == chn->idx) {
+			cairo_move_to(cr, start - 0.5, CYPOS(0));
+		} else {
+			cairo_move_to(cr, start - 0.5, CYPOS(chn->data_max[start]));
+		}
+
+		uint32_t pathlength = 0;
+		for (uint32_t i = start; i < end; ++i) {
+			if (i == chn->idx) {
+				continue;
+			} else if (i % 2) {
+				cairo_line_to(cr, i - .5, CYPOS(chn->data_min[i]));
+				cairo_line_to(cr, i - .5, CYPOS(chn->data_max[i]));
+				++pathlength;
+			} else {
+				cairo_line_to(cr, i - .5, CYPOS(chn->data_max[i]));
+				cairo_line_to(cr, i - .5, CYPOS(chn->data_min[i]));
+				++pathlength;
+			}
+
+			/** Limit the max cairo path length.  This is an optimization trade
+			    off: too short path: high load CPU/GPU load.  too-long path:
+			    bad anti-aliasing, or possibly lost points */
+			if (pathlength > MAX_CAIRO_PATH) {
+				pathlength = 0;
+				cairo_stroke(cr);
+				if (i % 2) {
+					cairo_move_to(cr, i - .5, CYPOS(chn->data_max[i]));
+				} else {
+					cairo_move_to(cr, i - .5, CYPOS(chn->data_min[i]));
+				}
+			}
+		}
+
+		if (pathlength > 0) {
+			cairo_stroke(cr);
+		}
+
+		// Draw current position vertical line if display is slow
+		if (ui->stride >= ui->rate / 4800.0f || ui->paused) {
+			cairo_set_source_rgba(cr, .9, .2, .2, .6);
+			cairo_move_to(cr, chn->idx - .5, DAHEIGHT * c);
+			cairo_line_to(cr, chn->idx - .5, DAHEIGHT * (c + 1));
+			cairo_stroke(cr);
+		}
+
+		// Undo the 'clipping' restriction
+		cairo_restore(cr);
+
+		// Channel separator
+		if (c > 0) {
+			cairo_set_source_rgba(cr, .5, .5, .5, 1.0);
+			cairo_move_to(cr, 0, DAHEIGHT * c - .5);
+			cairo_line_to(cr, DAWIDTH, DAHEIGHT * c - .5);
+			cairo_stroke(cr);
+		}
+
+		// Zero scale line
+		cairo_set_source_rgba(cr, .3, .3, .7, .5);
+		cairo_move_to(cr, 0, DAHEIGHT * (c + .5) - .5);
+		cairo_line_to(cr, DAWIDTH, DAHEIGHT * (c + .5) - .5);
+		cairo_stroke(cr);
+	}
+
+	cairo_destroy(cr);
+	return TRUE;
+}
+
+/**
+   Parse raw audio data and prepare for later drawing.
+ 
+   Note this is a toy example, which is really a waveform display, not an
+   oscilloscope.  A serious scope would not display samples as is.
+ 
+   Signals above ~ 1/10 of the sampling-rate will not yield a useful visual
+   display and result in a rather unintuitive representation of the actual
+   waveform.
+ 
+   Ideally the audio-data would be buffered and upsampled here and after that
+   written in a display buffer for later use.
+ 
+   For more information, see
+   https://wiki.xiph.org/Videos/Digital_Show_and_Tell
+   http://lac.linuxaudio.org/2013/papers/36.pdf
+   and https://github.com/x42/sisco.lv2
+*/
+static int
+process_channel(EgScopeUI*   ui,
+                ScoChan*     chn,
+                const size_t n_elem,
+                float const* data,
+                uint32_t*    idx_start,
+                uint32_t*    idx_end)
+{
+	int overflow = 0;
+	*idx_start = chn->idx;
+	for (size_t i = 0; i < n_elem; ++i) {
+		if (data[i] < chn->data_min[chn->idx]) {
+			chn->data_min[chn->idx] = data[i];
+		}
+		if (data[i] > chn->data_max[chn->idx]) {
+			chn->data_max[chn->idx] = data[i];
+		}
+		if (++chn->sub >= ui->stride) {
+			chn->sub = 0;
+			chn->idx = (chn->idx + 1) % DAWIDTH;
+			if (chn->idx == 0) {
+				++overflow;
+			}
+			chn->data_min[chn->idx] = 1.0;
+			chn->data_max[chn->idx] = -1.0;
+		}
+	}
+	*idx_end = chn->idx;
+	return overflow;
+}
+
+/**
+   Called via port_event() which is called by the host, typically at a rate of
+   around 25 FPS.
+*/
+static void
+update_scope(EgScopeUI*    ui,
+             const int32_t channel,
+             const size_t  n_elem,
+             float const*  data)
+{
+	// Never trust input data which could lead to application failure.
+	if (channel < 0 || (uint32_t)channel > ui->n_channels) {
+		return;
+	}
+
+	// Update state in sync with 1st channel
+	if (channel == 0) {
+		ui->stride = gtk_spin_button_get_value(GTK_SPIN_BUTTON(ui->spb_speed));
+		const bool paused = gtk_toggle_button_get_active(
+			GTK_TOGGLE_BUTTON(ui->btn_pause));
+
+		if (paused != ui->paused) {
+			ui->paused = paused;
+			gtk_widget_queue_draw(ui->darea);
+		}
+	}
+	if (ui->paused) {
+		return;
+	}
+
+	uint32_t idx_start;  // Display pixel start
+	uint32_t idx_end;    // Display pixel end
+	int      overflow;   // Received more audio-data than display-pixel
+
+	// Process this channel's audio-data for display
+	ScoChan* chn = &ui->chn[channel];
+	overflow = process_channel(ui, chn, n_elem, data, &idx_start, &idx_end);
+
+	// Signal gtk's main thread to redraw the widget after the last channel
+	if ((uint32_t)channel + 1 == ui->n_channels) {
+		if (overflow > 1) {
+			// Redraw complete widget
+			gtk_widget_queue_draw(ui->darea);
+		} else if (idx_end > idx_start) {
+			// Redraw area between start -> end pixel
+			gtk_widget_queue_draw_area(ui->darea, idx_start - 2, 0, 3
+			                           + idx_end - idx_start,
+			                           DAHEIGHT * ui->n_channels);
+		} else if (idx_end < idx_start) {
+			// Wrap-around: redraw area between 0->start AND end->right-end
+			gtk_widget_queue_draw_area(
+				ui->darea,
+				idx_start - 2, 0,
+				3 + DAWIDTH - idx_start, DAHEIGHT * ui->n_channels);
+			gtk_widget_queue_draw_area(
+				ui->darea,
+				0, 0,
+				idx_end + 1, DAHEIGHT * ui->n_channels);
+		}
+	}
+}
+
+static LV2UI_Handle
+instantiate(const LV2UI_Descriptor*   descriptor,
+            const char*               plugin_uri,
+            const char*               bundle_path,
+            LV2UI_Write_Function      write_function,
+            LV2UI_Controller          controller,
+            LV2UI_Widget*             widget,
+            const LV2_Feature* const* features)
+{
+	EgScopeUI* ui = (EgScopeUI*)malloc(sizeof(EgScopeUI));
+
+	if (!ui) {
+		fprintf(stderr, "EgScope.lv2 UI: out of memory\n");
+		return NULL;
+	}
+
+	ui->map = NULL;
+	*widget = NULL;
+
+	if (!strcmp(plugin_uri, SCO_URI "#Mono")) {
+		ui->n_channels = 1;
+	} else if (!strcmp(plugin_uri, SCO_URI "#Stereo")) {
+		ui->n_channels = 2;
+	} else {
+		free(ui);
+		return NULL;
+	}
+
+	for (int i = 0; features[i]; ++i) {
+		if (!strcmp(features[i]->URI, LV2_URID_URI "#map")) {
+			ui->map = (LV2_URID_Map*)features[i]->data;
+		}
+	}
+
+	if (!ui->map) {
+		fprintf(stderr, "EgScope.lv2 UI: Host does not support urid:map\n");
+		free(ui);
+		return NULL;
+	}
+
+	// Initialize private data structure
+	ui->write      = write_function;
+	ui->controller = controller;
+
+	ui->vbox   = NULL;
+	ui->hbox   = NULL;
+	ui->darea  = NULL;
+	ui->stride = 25;
+	ui->paused = false;
+	ui->rate   = 48000;
+
+	ui->chn[0].idx = 0;
+	ui->chn[0].sub = 0;
+	ui->chn[1].idx = 0;
+	ui->chn[1].sub = 0;
+	memset(ui->chn[0].data_min, 0, sizeof(float) * DAWIDTH);
+	memset(ui->chn[0].data_max, 0, sizeof(float) * DAWIDTH);
+	memset(ui->chn[1].data_min, 0, sizeof(float) * DAWIDTH);
+	memset(ui->chn[1].data_max, 0, sizeof(float) * DAWIDTH);
+
+	map_sco_uris(ui->map, &ui->uris);
+	lv2_atom_forge_init(&ui->forge, ui->map);
+
+	// Setup UI
+	ui->hbox = gtk_hbox_new(FALSE, 0);
+	ui->vbox = gtk_vbox_new(FALSE, 0);
+
+	ui->darea = gtk_drawing_area_new();
+	gtk_widget_set_size_request(ui->darea, DAWIDTH, DAHEIGHT * ui->n_channels);
+
+	ui->lbl_speed = gtk_label_new("Samples/Pixel");
+	ui->lbl_amp   = gtk_label_new("Amplitude");
+
+	ui->sep[0]    = gtk_hseparator_new();
+	ui->sep[1]    = gtk_label_new("");
+	ui->btn_pause = gtk_toggle_button_new_with_label("Pause");
+
+	ui->spb_speed_adj = (GtkAdjustment*)gtk_adjustment_new(
+			25.0, 1.0, 1000.0, 1.0, 5.0, 0.0);
+	ui->spb_speed = gtk_spin_button_new(ui->spb_speed_adj, 1.0, 0);
+
+	ui->spb_amp_adj = (GtkAdjustment*)gtk_adjustment_new(
+		1.0, 0.1, 6.0, 0.1, 1.0, 0.0);
+	ui->spb_amp = gtk_spin_button_new(ui->spb_amp_adj, 0.1, 1);
+
+	gtk_box_pack_start(GTK_BOX(ui->hbox), ui->darea,     FALSE, FALSE, 0);
+	gtk_box_pack_start(GTK_BOX(ui->hbox), ui->vbox,      FALSE, FALSE, 4);
+
+	gtk_box_pack_start(GTK_BOX(ui->vbox), ui->lbl_speed, FALSE, FALSE, 2);
+	gtk_box_pack_start(GTK_BOX(ui->vbox), ui->spb_speed, FALSE, FALSE, 2);
+	gtk_box_pack_start(GTK_BOX(ui->vbox), ui->sep[0],    FALSE, FALSE, 8);
+	gtk_box_pack_start(GTK_BOX(ui->vbox), ui->lbl_amp,   FALSE, FALSE, 2);
+	gtk_box_pack_start(GTK_BOX(ui->vbox), ui->spb_amp,   FALSE, FALSE, 2);
+	gtk_box_pack_start(GTK_BOX(ui->vbox), ui->sep[1],     TRUE, FALSE, 8);
+	gtk_box_pack_start(GTK_BOX(ui->vbox), ui->btn_pause, FALSE, FALSE, 2);
+
+	g_signal_connect(G_OBJECT(ui->darea), "expose_event",
+	                 G_CALLBACK(on_expose_event), ui);
+	g_signal_connect(G_OBJECT(ui->spb_amp), "value-changed",
+	                 G_CALLBACK(on_cfg_changed), ui);
+	g_signal_connect(G_OBJECT(ui->spb_speed), "value-changed",
+	                 G_CALLBACK(on_cfg_changed), ui);
+
+	*widget = ui->hbox;
+
+	/* Send UIOn message to plugin, which will request state and enable message
+	   transmission. */
+	send_ui_enable(ui);
+
+	return ui;
+}
+
+static void
+cleanup(LV2UI_Handle handle)
+{
+	EgScopeUI* ui = (EgScopeUI*)handle;
+	/* Send UIOff message to plugin, which will save state and disable message
+	 * transmission. */
+	send_ui_disable(ui);
+	gtk_widget_destroy(ui->darea);
+	free(ui);
+}
+
+static int
+recv_raw_audio(EgScopeUI* ui, LV2_Atom_Object* obj)
+{
+	LV2_Atom* chan_val = NULL;
+	LV2_Atom* data_val = NULL;
+	const int n_props  = lv2_atom_object_get(
+		obj,
+		ui->uris.channelID, &chan_val,
+		ui->uris.audioData, &data_val,
+		NULL);
+
+	if (n_props != 2 ||
+	    chan_val->type != ui->uris.atom_Int ||
+	    data_val->type != ui->uris.atom_Vector) {
+		// Object does not have the required properties with correct types
+		fprintf(stderr, "eg-scope.lv2 UI error: Corrupt audio message\n");
+		return 1;
+	}
+
+	// Get the values we need from the body of the property value atoms
+	const int32_t    chn = ((LV2_Atom_Int*)chan_val)->body;
+	LV2_Atom_Vector* vec = (LV2_Atom_Vector*)data_val;
+	if (vec->body.child_type != ui->uris.atom_Float) {
+		return 1;  // Vector has incorrect element type
+	}
+
+	// Number of elements = (total size - header size) / element size
+	const size_t n_elem = ((data_val->size - sizeof(LV2_Atom_Vector))
+	                       / sizeof(float));
+
+	// Float elements immediately follow the vector body header
+	const float* data = (float*)(&vec->body + 1);
+
+	// Update display
+	update_scope(ui, chn, n_elem, data);
+	return 0;
+}
+
+static int
+recv_ui_state(EgScopeUI* ui, LV2_Atom_Object* obj)
+{
+	LV2_Atom* spp_val  = NULL;
+	LV2_Atom* amp_val  = NULL;
+	LV2_Atom* rate_val = NULL;
+	const int n_props  = lv2_atom_object_get(
+		obj,
+		ui->uris.ui_spp, &spp_val,
+		ui->uris.ui_amp, &amp_val,
+		ui->uris.param_sampleRate, &rate_val,
+		NULL);
+
+	if (n_props != 3 ||
+		spp_val->type != ui->uris.atom_Int ||
+		amp_val->type != ui->uris.atom_Float ||
+	    rate_val->type != ui->uris.atom_Float) {
+		// Object does not have the required properties with correct types
+		fprintf(stderr, "eg-scope.lv2 UI error: Corrupt state message\n");
+		return 1;
+	}
+	
+	// Get the values we need from the body of the property value atoms
+	const int32_t spp  = ((LV2_Atom_Int*)spp_val)->body;
+	const float   amp  = ((LV2_Atom_Float*)amp_val)->body;
+	const float   rate = ((LV2_Atom_Float*)rate_val)->body;
+
+	// Update UI
+	gtk_spin_button_set_value(GTK_SPIN_BUTTON(ui->spb_speed), spp);
+	gtk_spin_button_set_value(GTK_SPIN_BUTTON(ui->spb_amp),   amp);
+	ui->rate = rate;
+
+	return 0;
+}
+
+/**
+   Receive data from the DSP-backend.
+ 
+   This is called by the host, typically at a rate of around 25 FPS.
+
+   Ideally this happens regularly and with relatively low latency, but there
+   are no hard guarantees about message delivery.
+*/
+static void
+port_event(LV2UI_Handle handle,
+           uint32_t     port_index,
+           uint32_t     buffer_size,
+           uint32_t     format,
+           const void*  buffer)
+{
+	EgScopeUI* ui   = (EgScopeUI*)handle;
+	LV2_Atom*  atom = (LV2_Atom*)buffer;
+
+	/* Check type of data received
+	 *  - format == 0: Control port event (float)
+	 *  - format > 0:  Message (atom)
+	 */
+	if (format == ui->uris.atom_eventTransfer &&
+	    atom->type == ui->uris.atom_Blank) {
+		LV2_Atom_Object* obj = (LV2_Atom_Object*)atom;
+		if (obj->body.otype == ui->uris.RawAudio) {
+			recv_raw_audio(ui, obj);
+		} else if (obj->body.otype == ui->uris.ui_State) {
+			recv_ui_state(ui, obj);
+		}
+	}
+}
+
+static const LV2UI_Descriptor descriptor = {
+	SCO_URI "#ui",
+	instantiate,
+	cleanup,
+	port_event,
+	NULL
+};
+
+LV2_SYMBOL_EXPORT
+const LV2UI_Descriptor*
+lv2ui_descriptor(uint32_t index)
+{
+	switch (index) {
+	case 0:
+		return &descriptor;
+	default:
+		return NULL;
+	}
+}
diff --git a/plugins/eg05-scope.lv2/manifest.ttl.in b/plugins/eg05-scope.lv2/manifest.ttl.in
new file mode 100644
index 0000000..028a673
--- /dev/null
+++ b/plugins/eg05-scope.lv2/manifest.ttl.in
@@ -0,0 +1,18 @@
+@prefix lv2:  <http://lv2plug.in/ns/lv2core#> .
+@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
+@prefix ui:   <http://lv2plug.in/ns/extensions/ui#> .
+
+<http://lv2plug.in/plugins/eg-scope#Mono>
+	a lv2:Plugin ;
+	lv2:binary <examploscope@LIB_EXT@>  ;
+	rdfs:seeAlso <examploscope.ttl> .
+
+<http://lv2plug.in/plugins/eg-scope#Stereo>
+	a lv2:Plugin ;
+	lv2:binary <examploscope@LIB_EXT@>  ;
+	rdfs:seeAlso <examploscope.ttl> .
+
+<http://lv2plug.in/plugins/eg-scope#ui>
+	a ui:GtkUI ;
+	ui:binary <examploscope_ui@LIB_EXT@> ;
+	rdfs:seeAlso <examploscope.ttl> .
diff --git a/plugins/eg05-scope.lv2/uris.h b/plugins/eg05-scope.lv2/uris.h
new file mode 100644
index 0000000..bd57551
--- /dev/null
+++ b/plugins/eg05-scope.lv2/uris.h
@@ -0,0 +1,73 @@
+/*
+  Copyright 2013 Robin Gareus <robin@gareus.org>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#ifndef SCO_URIS_H
+#define SCO_URIS_H
+
+#include "lv2/lv2plug.in/ns/ext/atom/atom.h"
+#include "lv2/lv2plug.in/ns/ext/atom/forge.h"
+#include "lv2/lv2plug.in/ns/ext/parameters/parameters.h"
+#include "lv2/lv2plug.in/ns/ext/urid/urid.h"
+
+#define SCO_URI "http://lv2plug.in/plugins/eg-scope"
+
+typedef struct {
+	// URIs defined in LV2 specifications
+	LV2_URID atom_Blank;
+	LV2_URID atom_Vector;
+	LV2_URID atom_Float;
+	LV2_URID atom_Int;
+	LV2_URID atom_eventTransfer;
+	LV2_URID param_sampleRate;
+
+	/* URIs defined for this plugin.  It is best to re-use existing URIs as
+	   much as possible, but plugins may need more vocabulary specific to their
+	   needs.  These are used as types and properties for plugin:UI
+	   communication, as well as for saving state. */
+	LV2_URID RawAudio;
+	LV2_URID channelID;
+	LV2_URID audioData;
+	LV2_URID ui_On;
+	LV2_URID ui_Off;
+	LV2_URID ui_State;
+	LV2_URID ui_spp;
+	LV2_URID ui_amp;
+} ScoLV2URIs;
+
+static inline void
+map_sco_uris(LV2_URID_Map* map, ScoLV2URIs* uris)
+{
+	uris->atom_Blank         = map->map(map->handle, LV2_ATOM__Blank);
+	uris->atom_Vector        = map->map(map->handle, LV2_ATOM__Vector);
+	uris->atom_Float         = map->map(map->handle, LV2_ATOM__Float);
+	uris->atom_Int           = map->map(map->handle, LV2_ATOM__Int);
+	uris->atom_eventTransfer = map->map(map->handle, LV2_ATOM__eventTransfer);
+	uris->param_sampleRate   = map->map(map->handle, LV2_PARAMETERS__sampleRate);
+
+	/* Note the convention that URIs for types are capitalized, and URIs for
+	   everything else (mainly properties) are not, just as in LV2
+	   specifications. */
+	uris->RawAudio  = map->map(map->handle, SCO_URI "#RawAudio");
+	uris->audioData = map->map(map->handle, SCO_URI "#audioData");
+	uris->channelID = map->map(map->handle, SCO_URI "#channelID");
+	uris->ui_On     = map->map(map->handle, SCO_URI "#UIOn");
+	uris->ui_Off    = map->map(map->handle, SCO_URI "#UIOff");
+	uris->ui_State  = map->map(map->handle, SCO_URI "#UIState");
+	uris->ui_spp    = map->map(map->handle, SCO_URI "#ui-spp");
+	uris->ui_amp    = map->map(map->handle, SCO_URI "#ui-amp");
+}
+
+#endif  /* SCO_URIS_H */
diff --git a/plugins/eg05-scope.lv2/wscript b/plugins/eg05-scope.lv2/wscript
new file mode 100644
index 0000000..807d15d
--- /dev/null
+++ b/plugins/eg05-scope.lv2/wscript
@@ -0,0 +1,73 @@
+#!/usr/bin/env python
+from waflib.extras import autowaf as autowaf
+import re
+
+# Variables for 'waf dist'
+APPNAME = 'eg-scope.lv2'
+VERSION = '1.0.0'
+
+# Mandatory variables
+top = '.'
+out = 'build'
+
+def options(opt):
+    opt.load('compiler_c')
+    autowaf.set_options(opt)
+
+def configure(conf):
+    conf.load('compiler_c')
+    autowaf.configure(conf)
+    autowaf.set_c99_mode(conf)
+    autowaf.display_header('Scope Configuration')
+
+    if not autowaf.is_child():
+        autowaf.check_pkg(conf, 'lv2', atleast_version='1.2.1', uselib_store='LV2')
+
+    autowaf.check_pkg(conf, 'cairo', uselib_store='CAIRO',
+                      atleast_version='1.8.10', mandatory=True)
+    autowaf.check_pkg(conf, 'gtk+-2.0', uselib_store='GTK2',
+                      atleast_version='2.18.0', mandatory=False)
+
+    autowaf.display_msg(conf, 'LV2 bundle directory', conf.env.LV2DIR)
+    print('')
+
+def build(bld):
+    bundle = 'eg-scope.lv2'
+
+    # Make a pattern for shared objects without the 'lib' prefix
+    module_pat = re.sub('^lib', '', bld.env.cshlib_PATTERN)
+    module_ext = module_pat[module_pat.rfind('.'):]
+
+    # Build manifest.ttl by substitution (for portable lib extension)
+    for i in ['manifest.ttl', 'examploscope.ttl']:
+        bld(features     = 'subst',
+            source       = i + '.in',
+            target       = '%s/%s' % (bundle, i),
+            install_path = '${LV2DIR}/%s' % bundle,
+            LIB_EXT      = module_ext)
+
+    # Use LV2 headers from parent directory if building as a sub-project
+    includes = ['.']
+    if autowaf.is_child:
+        includes += ['../..']
+
+    # Build plugin library
+    obj = bld(features     = 'c cshlib',
+              source       = 'examploscope.c',
+              name         = 'examploscope',
+              target       = '%s/examploscope' % bundle,
+              install_path = '${LV2DIR}/%s' % bundle,
+              use          = 'LV2',
+              includes     = includes)
+    obj.env.cshlib_PATTERN = module_pat
+
+    # Build UI library
+    if bld.is_defined('HAVE_GTK2'):
+        obj = bld(features     = 'c cshlib',
+                  source       = 'examploscope_ui.c',
+                  name         = 'examploscope_ui',
+                  target       = '%s/examploscope_ui' % bundle,
+                  install_path = '${LV2DIR}/%s' % bundle,
+                  use          = 'GTK2 CAIRO LV2',
+                  includes     = includes)
+    obj.env.cshlib_PATTERN = module_pat