Replace slider translation exponent with cubic-bezier curve presets + custom curve

ControlPad/EventHandler.cs

@@ -102,7 +102,7 @@
                                 {
                                     if (IsPressed && !IsPressedOld)
                                     {                                        
                                         AudioController.MuteProcess(buttonAction.ActionProperty, !AudioController.IsProcessMute(buttonAction.ActionProperty));
                                     }
                                     break;
                                 }
@@ -118,7 +118,7 @@
                                 {
                                     if (IsPressed && !IsPressedOld)
                                     {
                                         AudioController.MuteMic(buttonAction.ActionProperty, !AudioController.IsMicMute(buttonAction.ActionProperty));
                                     }
                                     break;
                                 }
@@ -126,7 +126,7 @@
                                 {
                                     if (IsPressed && !IsPressedOld)
                                     {
                                         string path = buttonAction.ActionProperty;
                                         try
                                         {
                                             Process.Start(new ProcessStartInfo
@@ -183,7 +183,14 @@
 
         private float SliderToFloat(int value, int mode = 0)
         {
-            return SliderValueConverter.SliderToFloat(value, Settings.TranslationExponent);
+            value -= 1;
+            float normalized = Math.Clamp((float)value / 1022.0f, 0f, 1f);
+
+            // Clamp to zero when slider is at or near the bottom to ensure complete silence
+            if (normalized < 0.005f)
+                return 0f;
+
+            return SliderTranslationCurve.Apply(normalized);
         }
     }
 }

ControlPad/Settings.cs

@@ -15,6 +15,11 @@ public static class Settings
         private static bool _startMinimized = false;
         private static bool _minimizeToSystemTray = true;
         private static double _translationExponent = 1d;
+        private static string _translationCurvePreset = "linear";
+        private static double _translationCurveX1 = 0d;
+        private static double _translationCurveY1 = 0d;
+        private static double _translationCurveX2 = 1d;
+        private static double _translationCurveY2 = 1d;
         private static int _selectedThemeIndex = 0;
         private static int _selectedBackgroundIndex = 3;
         private static int _sliderDeadZone = 4;
@@ -115,13 +120,68 @@ public static double TranslationExponent
             }
         }
 
+        public static string TranslationCurvePreset
+        {
+            get => _translationCurvePreset;
+            set
+            {
+                _translationCurvePreset = SliderTranslationCurve.IsSupportedPreset(value) ? value : "linear";
+                Save();
+            }
+        }
+
+        public static double TranslationCurveX1
+        {
+            get => _translationCurveX1;
+            set
+            {
+                _translationCurveX1 = Math.Clamp(value, 0d, 1d);
+                Save();
+            }
+        }
+
+        public static double TranslationCurveY1
+        {
+            get => _translationCurveY1;
+            set
+            {
+                _translationCurveY1 = Math.Clamp(value, 0d, 1d);
+                Save();
+            }
+        }
+
+        public static double TranslationCurveX2
+        {
+            get => _translationCurveX2;
+            set
+            {
+                _translationCurveX2 = Math.Clamp(value, 0d, 1d);
+                Save();
+            }
+        }
+
+        public static double TranslationCurveY2
+        {
+            get => _translationCurveY2;
+            set
+            {
+                _translationCurveY2 = Math.Clamp(value, 0d, 1d);
+                Save();
+            }
+        }
+
         private class Data
         {
             public bool TrayIconMessageShown { get; set; } = false;
             public bool StartWithWindows { get; set; } = false;
             public bool StartMinimized { get; set; } = true;
             public bool MinimizeToSystemTray { get; set; } = true;
             public double TranslationExponent { get; set; } = 1d;
+            public string TranslationCurvePreset { get; set; } = "linear";
+            public double TranslationCurveX1 { get; set; } = 0d;
+            public double TranslationCurveY1 { get; set; } = 0d;
+            public double TranslationCurveX2 { get; set; } = 1d;
+            public double TranslationCurveY2 { get; set; } = 1d;
             public int SelectedThemeIndex { get; set; } = 0;
             public int SelectedBackgroundIndex { get; set; } = 3;
             public int SliderDeadZone { get; set; } = 4;
@@ -148,6 +208,11 @@ public static void Load()
                 _selectedBackgroundIndex = data.SelectedBackgroundIndex;
                 _sliderDeadZone = data.SliderDeadZone;
                 _translationExponent = data.TranslationExponent;
+                _translationCurvePreset = SliderTranslationCurve.IsSupportedPreset(data.TranslationCurvePreset) ? data.TranslationCurvePreset : "linear";
+                _translationCurveX1 = Math.Clamp(data.TranslationCurveX1, 0d, 1d);
+                _translationCurveY1 = Math.Clamp(data.TranslationCurveY1, 0d, 1d);
+                _translationCurveX2 = Math.Clamp(data.TranslationCurveX2, 0d, 1d);
+                _translationCurveY2 = Math.Clamp(data.TranslationCurveY2, 0d, 1d);
                 _unmuteOnSliderChange = data.UnmuteOnSliderChange;
             }
             catch
@@ -170,6 +235,11 @@ private static void Save()
                     SelectedBackgroundIndex = _selectedBackgroundIndex,
                     SliderDeadZone = _sliderDeadZone,
                     TranslationExponent = _translationExponent,
+                    TranslationCurvePreset = _translationCurvePreset,
+                    TranslationCurveX1 = _translationCurveX1,
+                    TranslationCurveY1 = _translationCurveY1,
+                    TranslationCurveX2 = _translationCurveX2,
+                    TranslationCurveY2 = _translationCurveY2,
                     UnmuteOnSliderChange = _unmuteOnSliderChange,
                 };
 
@@ -183,4 +253,4 @@ private static void Save()
             }
         }
     }
-}
+}

ControlPad/SliderTranslationCurve.cs

@@ -0,0 +1,104 @@
+namespace ControlPad
+{
+    public static class SliderTranslationCurve
+    {
+        private const double Epsilon = 1e-6;
+        private const int MaxBisectionIterations = 20;
+        private static string? _lastPreset;
+        private static double _lastX1;
+        private static double _lastY1;
+        private static double _lastX2;
+        private static double _lastY2;
+        private static (double x1, double y1, double x2, double y2) _cachedControlPoints = (0d, 0d, 1d, 1d);
+
+        public static bool IsSupportedPreset(string? preset)
+        {
+            return preset is "ease" or "linear" or "ease-in" or "ease-out" or "ease-in-out" or "custom";
+        }
+
+        public static (double x1, double y1, double x2, double y2) GetPresetControlPoints(string preset)
+        {
+            return preset switch
+            {
+                "ease" => (0.25d, 0.1d, 0.25d, 1d),
+                "linear" => (0d, 0d, 1d, 1d),
+                "ease-in" => (0.42d, 0d, 1d, 1d),
+                "ease-out" => (0d, 0d, 0.58d, 1d),
+                "ease-in-out" => (0.42d, 0d, 0.58d, 1d),
+                _ => (0d, 0d, 1d, 1d),
+            };
+        }
+
+        public static float Apply(float input)
+        {
+            double t = Math.Clamp(input, 0f, 1f);
+            var controlPoints = GetControlPoints();
+
+            return (float)Evaluate(controlPoints.Item1, controlPoints.Item2, controlPoints.Item3, controlPoints.Item4, t);
+        }
+
+        private static (double x1, double y1, double x2, double y2) GetControlPoints()
+        {
+            string preset = Settings.TranslationCurvePreset;
+            double x1 = Settings.TranslationCurveX1;
+            double y1 = Settings.TranslationCurveY1;
+            double x2 = Settings.TranslationCurveX2;
+            double y2 = Settings.TranslationCurveY2;
+
+            if (_lastPreset == preset && _lastX1 == x1 && _lastY1 == y1 && _lastX2 == x2 && _lastY2 == y2)
+                return _cachedControlPoints;
+
+            _cachedControlPoints = preset == "custom"
+                ? (x1, y1, x2, y2)
+                : GetPresetControlPoints(preset);
+
+            _lastPreset = preset;
+            _lastX1 = x1;
+            _lastY1 = y1;
+            _lastX2 = x2;
+            _lastY2 = y2;
+            return _cachedControlPoints;
+        }
+
+        private static double Evaluate(double x1, double y1, double x2, double y2, double xTarget)
+        {
+            x1 = Math.Clamp(x1, 0d, 1d);
+            x2 = Math.Clamp(x2, 0d, 1d);
+            y1 = Math.Clamp(y1, 0d, 1d);
+            y2 = Math.Clamp(y2, 0d, 1d);
+            xTarget = Math.Clamp(xTarget, 0d, 1d);
+
+            if (xTarget <= 0d)
+                return 0d;
+            if (xTarget >= 1d)
+                return 1d;
+
+            double lower = 0d;
+            double upper = 1d;
+            double t = xTarget;
+
+            for (int i = 0; i < MaxBisectionIterations; i++)
+            {
+                t = (lower + upper) * 0.5d;
+                double x = Bezier(t, 0d, x1, x2, 1d);
+                if (Math.Abs(x - xTarget) < Epsilon)
+                    break;
+                if (x < xTarget)
+                    lower = t;
+                else
+                    upper = t;
+            }
+
+            return Bezier(t, 0d, y1, y2, 1d);
+        }
+
+        private static double Bezier(double t, double p0, double p1, double p2, double p3)
+        {
+            double oneMinusT = 1d - t;
+            return oneMinusT * oneMinusT * oneMinusT * p0
+                + 3d * oneMinusT * oneMinusT * t * p1
+                + 3d * oneMinusT * t * t * p2
+                + t * t * t * p3;
+        }
+    }
+}

ControlPad/UI Elements/SettingsUserControl.xaml

@@ -130,31 +130,74 @@
                           Unchecked="cb_UnmuteOnSliderChange_Checked"/>
                     </Grid>
 
-                    <!-- Translation Exponent -->
+                    <!-- Translation Curve -->
                     <Grid Margin="0,8,0,0" Grid.Row="5">
                         <Grid.ColumnDefinitions>
                             <ColumnDefinition/>
                             <ColumnDefinition Width="Auto"/>
                         </Grid.ColumnDefinitions>
 
                         <StackPanel Orientation="Vertical" Margin="0,0,16,0">
-                            <Label Content="Translation _exponent"
-                            Padding="0"
-                            Target="{Binding ElementName=ThemeComboBox}"/>
-                            <Label Content="Exponent controlling the mapping curve from slider to&#x0a;sound bar."
+                            <Label Content="Translation _curve"
+                             Padding="0"
+                             Target="{Binding ElementName=TranslationCurvePresetComboBox}"/>
+                            <Label Content="Curve controlling mapping from slider to sound level."
                             Padding="0"
                             Foreground="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
                         </StackPanel>
 
-                        <ui:NumberBox x:Name="nb_TranslationExponent"
-                        PlaceholderText="1.0" 
-                        Grid.ColumnSpan="2" 
-                        Margin="367,0,0,0" 
-                        Value="1.0"
-                        SmallChange="0.1"
-                        Minimum="0.1"
-                        ValidationMode="InvalidInputOverwritten" ValueChanged="nb_TranslationExponent_ValueChanged"
-                        />
+                        <StackPanel Grid.Column="1" Orientation="Vertical" MinWidth="180">
+                            <ComboBox x:Name="TranslationCurvePresetComboBox"
+                                      SelectedIndex="1"
+                                      VerticalAlignment="Center"
+                                      SelectionChanged="TranslationCurvePresetComboBox_SelectionChanged">
+                                <ComboBoxItem Content="ease"/>
+                                <ComboBoxItem Content="linear"/>
+                                <ComboBoxItem Content="ease-in"/>
+                                <ComboBoxItem Content="ease-out"/>
+                                <ComboBoxItem Content="ease-in-out"/>
+                                <ComboBoxItem Content="custom"/>
+                            </ComboBox>
+
+                            <UniformGrid x:Name="CustomCurveGrid" Columns="2" Rows="2" Margin="0,8,0,0">
+                                <ui:NumberBox x:Name="nb_CurveX1"
+                                              PlaceholderText="x1"
+                                              Value="0.0"
+                                              Minimum="0"
+                                              Maximum="1"
+                                              SmallChange="0.01"
+                                              Margin="0,0,6,6"
+                                              ValidationMode="InvalidInputOverwritten"
+                                              ValueChanged="nb_CustomCurve_ValueChanged"/>
+                                <ui:NumberBox x:Name="nb_CurveY1"
+                                              PlaceholderText="y1"
+                                              Value="0.0"
+                                              Minimum="0"
+                                              Maximum="1"
+                                              SmallChange="0.01"
+                                              Margin="6,0,0,6"
+                                              ValidationMode="InvalidInputOverwritten"
+                                              ValueChanged="nb_CustomCurve_ValueChanged"/>
+                                <ui:NumberBox x:Name="nb_CurveX2"
+                                              PlaceholderText="x2"
+                                              Value="1.0"
+                                              Minimum="0"
+                                              Maximum="1"
+                                              SmallChange="0.01"
+                                              Margin="0,0,6,0"
+                                              ValidationMode="InvalidInputOverwritten"
+                                              ValueChanged="nb_CustomCurve_ValueChanged"/>
+                                <ui:NumberBox x:Name="nb_CurveY2"
+                                              PlaceholderText="y2"
+                                              Value="1.0"
+                                              Minimum="0"
+                                              Maximum="1"
+                                              SmallChange="0.01"
+                                              Margin="6,0,0,0"
+                                              ValidationMode="InvalidInputOverwritten"
+                                              ValueChanged="nb_CustomCurve_ValueChanged"/>
+                            </UniformGrid>
+                        </StackPanel>
                     </Grid>
 
                     <!-- App Theme -->