Passed the valueToTextFunction and textToValueFunction lambdas from an AudioProcessorValueTreeState parameter to an attached slider

modules/juce_audio_processors/utilities/juce_AudioProcessorValueTreeState.cpp

@@ -421,7 +421,7 @@ struct AudioProcessorValueTreeState::SliderAttachment::Pimpl  : private Attached
     Pimpl (AudioProcessorValueTreeState& s, const String& p, Slider& sl)
         : AttachedControlBase (s, p), slider (sl), ignoreCallbacks (false)
     {
-        NormalisableRange<float> range (s.getParameterRange (paramID));
+        NormalisableRange<float> range (state.getParameterRange (paramID));
 
         if (range.interval != 0 || range.skew != 0)
         {
@@ -463,8 +463,13 @@ struct AudioProcessorValueTreeState::SliderAttachment::Pimpl  : private Attached
                                            snapToLegalValueFunction });
         }
 
-        if (auto* param = state.getParameter (paramID))
+        if (auto* param = dynamic_cast<AudioProcessorValueTreeState::Parameter*> (state.getParameter (paramID)))
+        {
+            slider.valueFromTextFunction = [param] (const String& text) { return (double) param->textToValueFunction (text); };
+            slider.textFromValueFunction = [param] (double value)       { return param->valueToTextFunction ((float) value); };
+
             slider.setDoubleClickReturnValue (true, range.convertFrom0to1 (param->getDefaultValue()));
+        }
 
         sendInitialUpdate();
         slider.addListener (this);

modules/juce_gui_basics/widgets/juce_Slider.cpp

@@ -1539,6 +1539,9 @@ String Slider::getTextValueSuffix() const
 
 String Slider::getTextFromValue (double v)
 {
+    if (textFromValueFunction != nullptr)
+        return textFromValueFunction (v);
+
     if (getNumDecimalPlacesToDisplay() > 0)
         return String (v, getNumDecimalPlacesToDisplay()) + getTextValueSuffix();
 
@@ -1547,6 +1550,9 @@ String Slider::getTextFromValue (double v)
 
 double Slider::getValueFromText (const String& text)
 {
+    if (valueFromTextFunction != nullptr)
+        return valueFromTextFunction (text);
+
     auto t = text.trimStart();
 
     if (t.endsWith (getTextValueSuffix()))

modules/juce_gui_basics/widgets/juce_Slider.h

@@ -602,6 +602,12 @@ public:
     /** You can assign a lambda to this callback object to have it called when the slider's drag ends. */
     std::function<void()> onDragEnd;
 
+    /** You can assign a lambda that will be used to convert textual values to the slider's normalised position. */
+    std::function<double (const String&)> valueFromTextFunction;
+
+    /** You can assign a lambda that will be used to convert the slider's normalised position to a textual value. */
+    std::function<String (double)> textFromValueFunction;
+
     //==============================================================================
     /** This lets you choose whether double-clicking moves the slider to a given position.