add a new AutomationType enum, LargeGainAutomation that provides +24dB of gain

libs/ardour/amp.cc

@@ -335,6 +335,7 @@ Amp::state () const
 	XMLNode& node (Processor::state ());
 	switch (_gain_control->parameter().type()) {
 		case GainAutomation:
+		case LargeGainAutomation:
 			node.set_property("type", "amp");
 			break;
 		case TrimAutomation:

libs/ardour/ardour/dB.h

@@ -45,5 +45,3 @@ static inline double dB_coeff_step(double max_coeff) {
 	return 0.1 * (max_coeff / max_db);
 }
 
-extern double zero_db_as_fraction;
-

libs/ardour/ardour/types.h

@@ -145,6 +145,7 @@ enum InsertMergePolicy {
  */
 enum AutomationType {
 	NullAutomation,
+	LargeGainAutomation,
 	GainAutomation,
 	PanAzimuthAutomation,
 	PanElevationAutomation,

libs/ardour/ardour/value_as_string.h

@@ -52,7 +52,9 @@ value_as_string(const ARDOUR::ParameterDescriptor& desc,
 	// Value is not a scale point, print it normally
 	if (desc.unit == ARDOUR::ParameterDescriptor::MIDI_NOTE) {
 		snprintf(buf, sizeof(buf), "%s", ParameterDescriptor::midi_note_name (rint(v)).c_str());
-	} else if (desc.type == GainAutomation || desc.type == BusSendLevel || desc.type == TrimAutomation || desc.type == EnvelopeAutomation || desc.type == MainOutVolume || desc.type == SurroundSendLevel || desc.type == InsertReturnLevel) {
+	} else if (desc.type == LargeGainAutomation || desc.type == GainAutomation || desc.type == BusSendLevel ||
+	           desc.type == TrimAutomation || desc.type == EnvelopeAutomation || desc.type == MainOutVolume ||
+	           desc.type == SurroundSendLevel || desc.type == InsertReturnLevel) {
 #ifdef PLATFORM_WINDOWS
 		if (v < GAIN_COEFF_SMALL) {
 			snprintf(buf, sizeof(buf), "-inf dB");

libs/ardour/automatable.cc

@@ -194,6 +194,8 @@ Automatable::describe_parameter (Evoral::Parameter param)
 
 	if (param == Evoral::Parameter(GainAutomation)) {
 		return _("Fader");
+	} else if (param == Evoral::Parameter(LargeGainAutomation)) {
+		return _("Fader");
 	} else if (param.type() == BusSendLevel) {
 		return _("Send");
 	} else if (param.type() == SurroundSendLevel) {
@@ -588,7 +590,7 @@ Automatable::control_factory(const Evoral::Parameter& param)
 		} else {
 			warning << "PluginPropertyAutomation for non-Plugin" << endl;
 		}
-	} else if (param.type() == GainAutomation) {
+	} else if (param.type() == GainAutomation || param.type() == GainAutomation) {
 		control = new GainControl(_a_session, param);
 	} else if (param.type() == TrimAutomation) {
 		control = new GainControl(_a_session, param);

libs/ardour/automation_list.cc

@@ -157,6 +157,7 @@ AutomationList::create_curve_if_necessary()
 {
 	switch (_parameter.type()) {
 	case GainAutomation:
+	case LargeGainAutomation:
 	case BusSendLevel:
 	case SurroundSendLevel:
 	case InsertReturnLevel:
@@ -234,6 +235,7 @@ AutomationList::default_interpolation () const
 {
 	switch (_parameter.type()) {
 		case GainAutomation:
+		case LargeGainAutomation:
 		case BusSendLevel:
 		case SurroundSendLevel:
 		case InsertReturnLevel:

libs/ardour/control_group.cc

@@ -227,6 +227,7 @@ ControlGroup::fill_from_stripable_list (StripableList& sl, Evoral::Parameter con
 
 	switch (p.type()) {
 	case GainAutomation:
+	case LargeGainAutomation:
 		for (auto & s : sl) {
 			std::shared_ptr<AutomationControl> ac = s->gain_control ();
 			if (ac) {

libs/ardour/enums.cc

@@ -184,6 +184,7 @@ setup_enum_writer ()
 
 	REGISTER_ENUM (NullAutomation);
 	REGISTER_ENUM (GainAutomation);
+	REGISTER_ENUM (LargeGainAutomation);
 	REGISTER_ENUM (PanAzimuthAutomation);
 	REGISTER_ENUM (PanElevationAutomation);
 	REGISTER_ENUM (PanWidthAutomation);

libs/ardour/event_type_map.cc

@@ -130,6 +130,8 @@ EventTypeMap::from_symbol(const string& str) const
 
 	if (str == "gain") {
 		p_type = GainAutomation;
+	} else if (str == "large-gain") {
+		p_type = LargeGainAutomation;
 	} else if (str == "send") {
 		p_type = BusSendLevel;
 	} else if (str == "surround-send") {
@@ -258,6 +260,8 @@ EventTypeMap::to_symbol(const Evoral::Parameter& param) const
 
 	if (t == GainAutomation) {
 		return "gain";
+	} else if (t == LargeGainAutomation) {
+		return "large-gain";
 	} else if (t == BusSendLevel) {
 		return "send";
 	} else if (t == BusSendEnable) {

libs/ardour/gain_control.cc

@@ -38,6 +38,8 @@ using namespace std;
 static std::string gain_control_name (Evoral::Parameter const& param)
 {
 	switch (param.type()) {
+		case LargeGainAutomation:
+			/* fallthrough */
 		case GainAutomation:
 			/* fallthrough */
 		case BusSendLevel:
@@ -62,6 +64,8 @@ static std::string gain_control_name (Evoral::Parameter const& param)
 static std::shared_ptr<AutomationList> automation_list_new (Evoral::Parameter const& param)
 {
 	switch (param.type()) {
+		case LargeGainAutomation:
+			/* fallthrough */
 		case GainAutomation:
 			/* fallthrough */
 		case BusSendLevel:

libs/ardour/luabindings.cc

@@ -2481,6 +2481,7 @@ LuaBindings::common (lua_State* L)
 
 		.beginNamespace ("AutomationType")
 		.addConst ("GainAutomation", ARDOUR::AutomationType(GainAutomation))
+		.addConst ("LargeGainAutomation", ARDOUR::AutomationType(LargeGainAutomation))
 		.addConst ("BusSendLevel", ARDOUR::AutomationType(BusSendLevel))
 		.addConst ("SurroundSendLevel", ARDOUR::AutomationType(SurroundSendLevel))
 		.addConst ("InsertReturnLevel", ARDOUR::AutomationType(InsertReturnLevel))

libs/ardour/parameter_descriptor.cc

@@ -64,6 +64,10 @@ ParameterDescriptor::ParameterDescriptor(const Evoral::Parameter& parameter)
 		upper  = Config->get_max_gain();
 		normal = 1.0f;
 		break;
+	case LargeGainAutomation:
+		upper  = 15.85; /* +24dB */
+		normal = 1.0f;
+		break;
 	case BusSendEnable:
 		upper  = 1.f;
 		normal = 1.f;
@@ -286,11 +290,11 @@ ParameterDescriptor::update_steps()
 	if (unit == ParameterDescriptor::MIDI_NOTE) {
 		step      = smallstep = 1;  // semitone
 		largestep = 12;             // octave
-	} else if (type == GainAutomation || type == TrimAutomation || type == BusSendLevel || type == MainOutVolume || type == SurroundSendLevel || type == InsertReturnLevel) {
+	} else if (type == LargeGainAutomation || type == GainAutomation || type == TrimAutomation || type == BusSendLevel || type == MainOutVolume || type == SurroundSendLevel || type == InsertReturnLevel) {
 		/* dB_coeff_step gives a step normalized for [0, max_gain].  This is
 		   like "slider position", so we convert from "slider position" to gain
 		   to have the correct unit here. */
-		largestep = position_to_gain (dB_coeff_step(upper));
+		largestep = position_to_gain (dB_coeff_step (upper));
 		step      = position_to_gain (largestep / 10.0);
 		smallstep = step;
 	} else if (logarithmic) {
@@ -401,6 +405,8 @@ ParameterDescriptor::to_interface (float val, bool rotary) const
 {
 	val = std::min (upper, std::max (lower, val));
 	switch(type) {
+		case LargeGainAutomation:
+			/* fallthrough */
 		case GainAutomation:
 			/* fallthrough */
 		case BusSendLevel:
@@ -468,6 +474,7 @@ ParameterDescriptor::from_interface (float val, bool rotary) const
 
 	switch(type) {
 		case GainAutomation:
+		case LargeGainAutomation:
 		case EnvelopeAutomation:
 		case BusSendLevel:
 		case InsertReturnLevel:
@@ -532,6 +539,7 @@ ParameterDescriptor::is_linear () const
 	}
 	switch(type) {
 		case GainAutomation:
+		case LargeGainAutomation:
 		case EnvelopeAutomation:
 		case BusSendLevel:
 		case SurroundSendLevel:

libs/ardour/route.cc

@@ -3074,7 +3074,8 @@ Route::set_state_2X (const XMLNode& node, int version)
 					_main_outs->panner_shell()->set_state(*io_child, version);
 				} else if (io_child->name() == X_("Automation")) {
 					/* IO's automation is for the fader */
-					_amp->set_automation_xml_state (*io_child, Evoral::Parameter (GainAutomation));
+					AutomationType at = is_master() ? LargeGainAutomation : GainAutomation;
+					_amp->set_automation_xml_state (*io_child, Evoral::Parameter (at));
 				}
 			}
 		}

libs/ardour/send.cc

@@ -369,7 +369,7 @@ Send::set_state (const XMLNode& node, int version)
 				continue;
 			}
 			Evoral::Parameter param = EventTypeMap::instance().from_symbol (id_prop->value());
-			if (param.type() != GainAutomation) {
+			if (param.type() != GainAutomation && param.type() != LargeGainAutomation) {
 				continue;
 			}
 			XMLNode xn (**i);

libs/surfaces/mackie/mackie_control_protocol.cc

@@ -2103,6 +2103,7 @@ MackieControlProtocol::down_controls (AutomationType p, uint32_t pressed)
 	pull_stripable_range (m->second, stripables, pressed);
 
 	switch (p) {
+	case LargeGainAutomation:
 	case GainAutomation:
 		for (StripableList::iterator s = stripables.begin(); s != stripables.end(); ++s) {
 			controls.push_back ((*s)->gain_control());

libs/surfaces/mackie/strip.cc

@@ -713,6 +713,7 @@ Strip::format_parameter_for_display(
 
 	switch (desc.type) {
 	case GainAutomation:
+	case LargeGainAutomation:
 	case BusSendLevel:
 	case TrimAutomation:
 	case SurroundSendLevel:

libs/surfaces/maschine2/ui_knob.cc

@@ -222,6 +222,7 @@ Maschine2Knob::controllable_changed ()
 				break;
 
 			case ARDOUR::GainAutomation:
+			case ARDOUR::LargeGainAutomation:
 			case ARDOUR::BusSendLevel:
 			case ARDOUR::SurroundSendLevel:
 			case ARDOUR::InsertReturnLevel:

libs/surfaces/us2400/us2400_control_protocol.cc

@@ -1639,6 +1639,7 @@ US2400Protocol::down_controls (AutomationType p, uint32_t pressed)
 
 	switch (p) {
 	case GainAutomation:
+	case LargeGainAutomation:
 		for (StripableList::iterator s = stripables.begin(); s != stripables.end(); ++s) {
 			controls.push_back ((*s)->gain_control());
 		}

libs/widgets/ardour_fader.cc

@@ -22,6 +22,8 @@
 #include <iostream>
 #include <assert.h>
 
+#include "ardour/utils.h"
+
 #include "gtkmm2ext/cairo_widget.h"
 #include "gtkmm2ext/colors.h"
 #include "gtkmm2ext/keyboard.h"
@@ -59,6 +61,8 @@ ArdourFader::ArdourFader (Gtk::Adjustment& adj, int orientation, int fader_lengt
 	, have_explicit_fg (false)
 	, outline_color (0)
 {
+	adj.signal_changed().connect (sigc::mem_fun (*this, &ArdourFader::update_unity_position));
+
 	update_unity_position ();
 
 	add_events (Gdk::TOUCH_UPDATE_MASK);