Add SvgLatch.

include/app/SvgLatch.hpp

@@ -0,0 +1,25 @@
+#pragma once
+#include <app/common.hpp>
+#include <app/SvgSwitch.hpp>
+
+
+namespace rack {
+namespace app {
+
+
+/** A ParamWidget that behaves like a Switch but draws SVG frames for mouse up/down state.
+*/
+struct SvgLatch : SvgSwitch {
+	struct Internal;
+	Internal* internal;
+
+	SvgLatch();
+	~SvgLatch();
+	void onDragStart(const DragStartEvent& e) override;
+	void onDragEnd(const DragEndEvent& e) override;
+	void onChange(const ChangeEvent& e) override;
+};
+
+
+} // namespace app
+} // namespace rack

include/componentlibrary.hpp

@@ -6,6 +6,7 @@
 #include <app/SvgPort.hpp>
 #include <app/ModuleLightWidget.hpp>
 #include <app/SvgSwitch.hpp>
+#include <app/SvgLatch.hpp>
 #include <app/SvgScrew.hpp>
 #include <app/AudioWidget.hpp>
 #include <app/MidiWidget.hpp>
@@ -840,6 +841,13 @@ struct LEDButton : app::SvgSwitch {
 	}
 };
 
+struct LEDLatch : app::SvgLatch {
+	LEDLatch() {
+		addFrame(Svg::load(asset::system("res/ComponentLibrary/LEDButton.svg")));
+		addFrame(Svg::load(asset::system("res/ComponentLibrary/LEDButton_1.svg")));
+	}
+};
+
 template <typename TLight>
 struct LEDLightButton : LEDButton {
 	app::ModuleLightWidget* light;
@@ -856,6 +864,22 @@ struct LEDLightButton : LEDButton {
 	}
 };
 
+template <typename TLight>
+struct LEDLightLatch : LEDLatch {
+	app::ModuleLightWidget* light;
+
+	LEDLightLatch() {
+		light = new TLight;
+		// Move center of light to center of box
+		light->box.pos = box.size.div(2).minus(light->box.size.div(2));
+		addChild(light);
+	}
+
+	app::ModuleLightWidget* getLight() {
+		return light;
+	}
+};
+
 struct BefacoSwitch : app::SvgSwitch {
 	BefacoSwitch() {
 		addFrame(Svg::load(asset::system("res/ComponentLibrary/BefacoSwitch_0.svg")));

include/rack.hpp

@@ -87,6 +87,7 @@ Directly including Rack headers other than rack.hpp in your plugin is unsupporte
 #include <app/ModuleWidget.hpp>
 #include <app/SvgSlider.hpp>
 #include <app/SvgButton.hpp>
+#include <app/SvgLatch.hpp>
 
 #include <engine/Param.hpp>
 #include <engine/ParamHandle.hpp>

src/app/SvgLatch.cpp

@@ -0,0 +1,74 @@
+#include <app/SvgLatch.hpp>
+
+
+namespace rack {
+namespace app {
+
+
+struct SvgLatch::Internal {
+	bool unlatch = false;
+};
+
+
+SvgLatch::SvgLatch() {
+	internal = new Internal;
+}
+
+
+SvgLatch::~SvgLatch() {
+	delete internal;
+}
+
+
+void SvgLatch::onDragStart(const DragStartEvent& e) {
+	ParamWidget::onDragStart(e);
+	if (e.button != GLFW_MOUSE_BUTTON_LEFT)
+		return;
+
+	// Set value
+	engine::ParamQuantity* pq = getParamQuantity();
+	if (pq) {
+		if (pq->isMax()) {
+			internal->unlatch = true;
+		}
+		else {
+			pq->setMax();
+		}
+	}
+	// Set down frame
+	if (frames.size() >= 2) {
+		sw->setSvg(frames[1]);
+		fb->setDirty();
+	}
+}
+
+
+void SvgLatch::onDragEnd(const DragEndEvent& e) {
+	ParamWidget::onDragEnd(e);
+	if (e.button != GLFW_MOUSE_BUTTON_LEFT)
+		return;
+
+	// Set value
+	engine::ParamQuantity* pq = getParamQuantity();
+	if (pq) {
+		if (internal->unlatch) {
+			internal->unlatch = false;
+			pq->setMin();
+		}
+	}
+	// Set up frame
+	if (frames.size() >= 1) {
+		sw->setSvg(frames[0]);
+		fb->setDirty();
+	}
+}
+
+
+void SvgLatch::onChange(const ChangeEvent& e) {
+	// Bypass SvgSwitch behavior
+	Switch::onChange(e);
+}
+
+
+} // namespace app
+} // namespace rack

src/app/SvgSwitch.cpp

@@ -36,7 +36,7 @@ void SvgSwitch::onChange(const ChangeEvent& e) {
 		int index = (int) std::round(pq->getValue() - pq->getMinValue());
 		index = math::clamp(index, 0, (int) frames.size() - 1);
 		sw->setSvg(frames[index]);
-		fb->dirty = true;
+		fb->setDirty();
 	}
 	ParamWidget::onChange(e);
 }

src/app/Switch.cpp

@@ -10,8 +10,9 @@ namespace app {
 
 
 struct Switch::Internal {
-	/** Hysteresis state for momentary switch */
+	/** Whether momentary switch was pressed this frame. */
 	bool momentaryPressed = false;
+	/** Whether momentary switch was released this frame. */
 	bool momentaryReleased = false;
 };