Implement a slider widget for volume control that returns an exponentially scaled value

AUTHORS

@@ -109,6 +109,7 @@ Also thanks to:
     * Muh
     * Mustafa Alperen Seki (MustaphaTR)
     * Neil Shivkar (havok13888)
+    * Nikolay Fomin (netnazgul)
     * Nooze
     * Nukem
     * Okunev Yu Dmitry (xaionaro)

OpenRA.Mods.Common/OpenRA.Mods.Common.csproj

@@ -619,6 +619,7 @@
     <Compile Include="UtilityCommands\PngSheetExportMetadataCommand.cs" />
     <Compile Include="UtilityCommands\PngSheetImportMetadataCommand.cs" />
     <Compile Include="Widgets\Logic\Editor\ActorEditLogic.cs" />
+    <Compile Include="Widgets\ExponentialSliderWidget.cs" />
     <Compile Include="Widgets\Logic\MusicHotkeyLogic.cs" />
     <Compile Include="WorldExtensions.cs" />
     <Compile Include="UtilityCommands\GetMapHashCommand.cs" />

OpenRA.Mods.Common/Widgets/ExponentialSliderWidget.cs

@@ -0,0 +1,53 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2018 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System;
+using System.Drawing;
+using OpenRA.Graphics;
+using OpenRA.Widgets;
+
+namespace OpenRA.Mods.Common.Widgets
+{
+	public class ExponentialSliderWidget : SliderWidget
+	{
+		// Values are according to https://www.dr-lex.be/info-stuff/volumecontrols.html
+		public double ExpA = 1.0e-3;
+		public double ExpB = 6.908;
+
+		public ExponentialSliderWidget() :
+			base() { }
+		public ExponentialSliderWidget(ExponentialSliderWidget other) :
+			base(other) { }
+
+		float ExpFromLinear(float x)
+		{
+			if (x <= 0)
+				return 0;
+
+			return (float)(ExpA * Math.Exp(ExpB * x)).Clamp(0.0, 1.0);
+		}
+
+		float LinearFromExp(float x)
+		{
+			return (float)(Math.Log(x / ExpA) / ExpB).Clamp(0.0, 1.0);
+		}
+
+		protected override float ValueFromPx(int x)
+		{
+			return MinimumValue + (MaximumValue - MinimumValue) * ExpFromLinear((x - 0.5f * RenderBounds.Height) / (RenderBounds.Width - RenderBounds.Height));
+		}
+
+		protected override int PxFromValue(float x)
+		{
+			return (int)(0.5f * RenderBounds.Height + (RenderBounds.Width - RenderBounds.Height) * LinearFromExp((x - MinimumValue) / (MaximumValue - MinimumValue)));
+		}
+	}
+}

OpenRA.Mods.Common/Widgets/SliderWidget.cs

@@ -84,12 +84,12 @@ namespace OpenRA.Mods.Common.Widgets
 			return ThumbRect.Contains(mi.Location);
 		}
 
-		float ValueFromPx(int x)
+		protected virtual float ValueFromPx(int x)
 		{
 			return MinimumValue + (MaximumValue - MinimumValue) * (x - 0.5f * RenderBounds.Height) / (RenderBounds.Width - RenderBounds.Height);
 		}
 
-		protected int PxFromValue(float x)
+		protected virtual int PxFromValue(float x)
 		{
 			return (int)(0.5f * RenderBounds.Height + (RenderBounds.Width - RenderBounds.Height) * (x - MinimumValue) / (MaximumValue - MinimumValue));
 		}

mods/cnc/chrome/lobby-music.yaml

@@ -138,12 +138,12 @@ Container@LOBBY_MUSIC_BIN:
 					Height: 25
 					Align: Right
 					Text: Volume:
-				Slider@MUSIC_SLIDER:
+				ExponentialSlider@MUSIC_SLIDER:
 					X: 70
 					Y: 186
 					Width: PARENT_RIGHT - 80
 					Height: 20
-					Ticks: 5
+					Ticks: 7
 		ScrollPanel@MUSIC_LIST:
 			X: 307
 			Width: PARENT_RIGHT - 307

mods/cnc/chrome/music.yaml

@@ -128,12 +128,12 @@ Container@MUSIC_PANEL:
 									Height: 16
 									ImageCollection: music
 									ImageName: next
-						Slider@MUSIC_SLIDER:
+						ExponentialSlider@MUSIC_SLIDER:
 							X: 145
 							Y: 3
 							Width: 185
 							Height: 20
-							Ticks: 5
+							Ticks: 7
 				Label@TIME_LABEL:
 					X: (PARENT_RIGHT - WIDTH) / 2
 					Y: 315

mods/cnc/chrome/settings.yaml

@@ -277,12 +277,12 @@ Container@SETTINGS_PANEL:
 							Height: 25
 							Align: Right
 							Text: Sound Volume:
-						Slider@SOUND_VOLUME:
+						ExponentialSlider@SOUND_VOLUME:
 							X: PARENT_RIGHT - WIDTH - 15
 							Y: 43
 							Width: 250
 							Height: 20
-							Ticks: 5
+							Ticks: 7
 						Checkbox@CASH_TICKS:
 							X: 15
 							Y: 40
@@ -304,12 +304,12 @@ Container@SETTINGS_PANEL:
 							Height: 25
 							Align: Right
 							Text: Music Volume:
-						Slider@MUSIC_VOLUME:
+						ExponentialSlider@MUSIC_VOLUME:
 							X: PARENT_RIGHT - WIDTH - 15
 							Y: 73
 							Width: 250
 							Height: 20
-							Ticks: 5
+							Ticks: 7
 						Label@VIDEO_LABEL:
 							X: PARENT_RIGHT - WIDTH - 270
 							Y: 97
@@ -317,12 +317,12 @@ Container@SETTINGS_PANEL:
 							Height: 25
 							Align: Right
 							Text: Video Volume:
-						Slider@VIDEO_VOLUME:
+						ExponentialSlider@VIDEO_VOLUME:
 							X: PARENT_RIGHT - WIDTH - 15
 							Y: 103
 							Width: 250
 							Height: 20
-							Ticks: 5
+							Ticks: 7
 						Label@AUDIO_DEVICE_LABEL:
 							X: 190 - WIDTH - 5
 							Y: 244

mods/common/chrome/lobby-music.yaml

@@ -128,12 +128,12 @@ Container@LOBBY_MUSIC_BIN:
 					Height: 25
 					Align: Right
 					Text: Volume:
-				Slider@MUSIC_SLIDER:
+				ExponentialSlider@MUSIC_SLIDER:
 					X: 70
 					Y: 186
 					Width: PARENT_RIGHT - 80
 					Height: 20
-					Ticks: 5
+					Ticks: 7
 		ScrollPanel@MUSIC_LIST:
 			X: 268
 			Width: PARENT_RIGHT - 268

mods/common/chrome/musicplayer.yaml

@@ -116,12 +116,12 @@ Background@MUSIC_PANEL:
 							Height: 25
 							ImageCollection: music
 							ImageName: next
-				Slider@MUSIC_SLIDER:
+				ExponentialSlider@MUSIC_SLIDER:
 					X: 145
 					Y: 3
 					Width: 175
 					Height: 20
-					Ticks: 5
+					Ticks: 7
 		Label@TIME_LABEL:
 			X: (PARENT_RIGHT - WIDTH) / 2
 			Y: 330

mods/common/chrome/settings.yaml

@@ -285,12 +285,12 @@ Background@SETTINGS_PANEL:
 					Height: 25
 					Align: Right
 					Text: Sound Volume:
-				Slider@SOUND_VOLUME:
+				ExponentialSlider@SOUND_VOLUME:
 					X: PARENT_RIGHT - WIDTH - 15
 					Y: 43
 					Width: 250
 					Height: 20
-					Ticks: 5
+					Ticks: 7
 				Checkbox@CASH_TICKS:
 					X: 15
 					Y: 40
@@ -312,12 +312,12 @@ Background@SETTINGS_PANEL:
 					Height: 25
 					Align: Right
 					Text: Music Volume:
-				Slider@MUSIC_VOLUME:
+				ExponentialSlider@MUSIC_VOLUME:
 					X: PARENT_RIGHT - WIDTH - 15
 					Y: 73
 					Width: 250
 					Height: 20
-					Ticks: 5
+					Ticks: 7
 				Label@VIDEO_LABEL:
 					X: PARENT_RIGHT - WIDTH - 270
 					Y: 97
@@ -325,12 +325,12 @@ Background@SETTINGS_PANEL:
 					Height: 25
 					Align: Right
 					Text: Video Volume:
-				Slider@VIDEO_VOLUME:
+				ExponentialSlider@VIDEO_VOLUME:
 					X: PARENT_RIGHT - WIDTH - 15
 					Y: 103
 					Width: 250
 					Height: 20
-					Ticks: 5
+					Ticks: 7
 				Label@AUDIO_DEVICE_LABEL:
 					X: 190 - WIDTH - 5
 					Y: 244