Make it possible to alter the scaling of parameters in ReaKontrol FX maps.

readme.md

@@ -77,6 +77,8 @@ ReaComp: # This is optional and overrides the FX name reported to users.
 --- # Page break. The remaining knobs on this page will be unassigned.
 [mix] # This is a section name for the following knobs.
 6 # Parameter 6 will be mapped to the first knob on the second page.
+10 /8 dry dB # Adjustments will be 8 times smaller than usual for this parameter.
+11 *8 # Adjustments will be 8 times larger than usual for this parameter.
 ```
 
 ReaKontrol can help you create these maps.

src/fxMap.cpp

@@ -22,8 +22,9 @@
 static const std::regex RE_STRIP(R"(^\s+|\s*#.*$|\s+$)");
 // The map name, ending with a colon.
 static const std::regex RE_MAP_NAME("(.*):");
-// A parameter number, optionally followed by space and a name.
-static const std::regex RE_PARAM(R"((\d+)(?:\s+(.+))?)");
+// A parameter number, optionally followed by space and a scaling factor (/n or
+// *n), optionally followed by space and a name.
+static const std::regex RE_PARAM(R"((\d+)(?:\s+([/*])(\d+))?(?:\s+(.+))?)");
 // A section name in square brackets.
 static const std::regex RE_SECTION(R"(\[(.+)\])");
 
@@ -101,7 +102,13 @@ FxMap::FxMap(MediaTrack* track, int fx) : _track(track), _fx(fx) {
 			const int mp = this->_reaperParams.size();
 			this->_reaperParams.push_back(rp);
 			this->_mapParams.insert({rp, mp});
-			const std::string paramName = m.str(2);
+			const std::string scaleType = m.str(2);
+			if (!scaleType.empty()) {
+				const int factor = std::atoi(m.str(3).c_str());
+				this->_paramMultipliers.insert({mp,
+					scaleType == "/" ? (1.0 / factor) : factor});
+			}
+			const std::string paramName = m.str(4);
 			if (!paramName.empty()) {
 				this->_paramNames.insert({mp, paramName});
 			}
@@ -170,6 +177,14 @@ std::string FxMap::getParamName(int mapParam) const {
 	return it->second;
 }
 
+double FxMap::getParamMultiplier(int mapParam) const {
+	auto it = this->_paramMultipliers.find(mapParam);
+	if (it == this->_paramMultipliers.end()) {
+		return 1.0;
+	}
+	return it->second;
+}
+
 std::string FxMap::getSection(int mapParam) const {
 	auto it = this->_sections.find(mapParam);
 	if (it == this->_sections.end()) {

src/fxMap.h

@@ -23,6 +23,7 @@ class FxMap {
 	int getReaperParam(int mapParam) const;
 	int getMapParam(int reaperParam) const;
 	std::string getParamName(int mapParam) const;
+	double getParamMultiplier(int mapParam) const;
 	std::string getSection(int mapParam) const;
 	std::string getSectionsForPage(int mapParam) const;
 
@@ -35,6 +36,7 @@ class FxMap {
 	int _fx = -1;
 	std::vector<int> _reaperParams;
 	std::map<int, std::string> _paramNames;
+	std::map<int, double> _paramMultipliers;
 	std::map<int, int> _mapParams;
 	std::map<int, std::string> _sections;
 };

src/niMidi.cpp

@@ -978,7 +978,7 @@ class NiMidiSurface: public BaseSurface {
 			val = TrackFX_GetParamNormalized(this->_lastSelectedTrack,
 				this->_selectedFx, param);
 		}
-		val += change;
+		val += change * this->_fxMap.getParamMultiplier(mp);
 		val = clamp(val, 0.0, 1.0);
 		TrackFX_SetParamNormalized(this->_lastSelectedTrack, this->_selectedFx, param,
 			val);