Fake parameter change when clicking host parameter module

plugins/Cardinal/src/HostParameters.cpp

@@ -81,6 +81,20 @@ struct HostParameters : Module {
     }
 };
 
+#ifndef HEADLESS
+struct CardinalParameterPJ301MPort : PJ301MPort {
+	void onDragStart(const DragStartEvent& e) override {
+        if (CardinalPluginContext* const pcontext = reinterpret_cast<CardinalPluginContext*>(APP))
+            handleHostParameterDrag(pcontext, portId, true);
+        PJ301MPort::onDragStart(e);
+    }
+	void onDragEnd(const DragEndEvent& e) override {
+        if (CardinalPluginContext* const pcontext = reinterpret_cast<CardinalPluginContext*>(APP))
+            handleHostParameterDrag(pcontext, portId, false);
+        PJ301MPort::onDragEnd(e);
+    }
+};
+
 struct HostParametersWidget : ModuleWidget {
     static constexpr const float startX = 10.0f;
     static constexpr const float startY = 90.0f;
@@ -101,7 +115,7 @@ struct HostParametersWidget : ModuleWidget {
         {
             const float x = startX + int(i / 6) * paddingH;
             const float y = startY + int(i % 6) * paddingV;
-            addOutput(createOutput<PJ301MPort>(Vec(x, y), module, i));
+            addOutput(createOutput<CardinalParameterPJ301MPort>(Vec(x, y), module, i));
         }
     }
 
@@ -139,5 +153,9 @@ struct HostParametersWidget : ModuleWidget {
         ModuleWidget::draw(args);
     }
 };
+#else
+typedef ModuleWidget HostParametersWidget;
+#endif
+
 
 Model* modelHostParameters = createModel<HostParameters, HostParametersWidget>("HostParameters");

plugins/Cardinal/src/plugincontext.hpp

@@ -60,6 +60,10 @@ struct CardinalPluginContext : rack::Context {
 #endif
 };
 
+#ifndef HEADLESS
+void handleHostParameterDrag(CardinalPluginContext* pcontext, uint index, bool started);
+#endif
+
 END_NAMESPACE_DISTRHO
 
 // -----------------------------------------------------------------------------------------------------------

src/CardinalUI.cpp

@@ -180,6 +180,21 @@ void CardinalPluginContext::removeIdleCallback(IdleCallback* const cb)
     ui->removeIdleCallback(cb);
 }
 
+void handleHostParameterDrag(CardinalPluginContext* pcontext, uint index, bool started)
+{
+    DISTRHO_SAFE_ASSERT_RETURN(pcontext->ui != nullptr,);
+
+    if (started)
+    {
+        pcontext->ui->editParameter(index, true);
+        pcontext->ui->setParameterValue(index, pcontext->parameters[index]);
+    }
+    else
+    {
+        pcontext->ui->editParameter(index, false);
+    }
+}
+
 // -----------------------------------------------------------------------------------------------------------
 
 class CardinalUI : public CardinalBaseUI,

src/PluginContext.hpp

@@ -95,6 +95,10 @@ struct CardinalPluginContext : rack::Context {
 #endif
 };
 
+#ifndef HEADLESS
+void handleHostParameterDrag(CardinalPluginContext* pcontext, uint index, bool started);
+#endif
+
 // -----------------------------------------------------------------------------------------------------------
 
 struct CardinalAudioDevice;