Use drag/edit for UI parameter example, cleanup

Signed-off-by: falkTX <falktx@falktx.com>

distrho/src/DistrhoPluginVST2.cpp

@@ -94,10 +94,10 @@ typedef struct _VstTimeInfo {
 typedef std::map<const String, String> StringMap;
 
 #if ! DISTRHO_PLUGIN_WANT_MIDI_OUTPUT
-static const writeMidiFunc writeMidiCallback = nullptr;
+static constexpr const writeMidiFunc writeMidiCallback = nullptr;
 #endif
 #if ! DISTRHO_PLUGIN_WANT_PARAMETER_VALUE_CHANGE_REQUEST
-static const requestParameterValueChangeFunc requestParameterValueChangeCallback = nullptr;
+static constexpr const requestParameterValueChangeFunc requestParameterValueChangeCallback = nullptr;
 #endif
 
 // --------------------------------------------------------------------------------------------------------------------

examples/Parameters/ExampleUIParameters.cpp

@@ -212,7 +212,9 @@ protected:
                 fParamGrid[index] = !fParamGrid[index];
 
                 // report change to host (and thus plugin)
+                editParameter(index, true);
                 setParameterValue(index, fParamGrid[index] ? 1.0f : 0.0f);
+                editParameter(index, false);
 
                 // trigger repaint
                 repaint();
@@ -227,7 +229,9 @@ protected:
                 // same as before
                 const uint32_t index = 3+i;
                 fParamGrid[index] = !fParamGrid[index];
+                editParameter(index, true);
                 setParameterValue(index, fParamGrid[index] ? 1.0f : 0.0f);
+                editParameter(index, false);
                 repaint();
                 break;
             }
@@ -240,7 +244,9 @@ protected:
                 // same as before
                 const uint32_t index = 6+i;
                 fParamGrid[index] = !fParamGrid[index];
+                editParameter(index, true);
                 setParameterValue(index, fParamGrid[index] ? 1.0f : 0.0f);
+                editParameter(index, false);
                 repaint();
                 break;
             }