Add a new option to put a transparent background on the strumline

source/funkin/Preferences.hx

@@ -199,6 +199,26 @@ class Preferences
   public static var lockedFramerateFunction = untyped js.Syntax.code("window.requestAnimationFrame");
   #end
 
+  /**
+   * If >0, the game will display a semi-opaque background under the notes.
+   * `0` for no background, `100` for solid black if you're freaky like that
+   * @default `0`
+   */
+  public static var strumlineBackgroundOpacity(get, set):Int;
+
+  static function get_strumlineBackgroundOpacity():Int
+  {
+    return (Save?.instance?.options?.strumlineBackgroundOpacity ?? 0);
+  }
+
+  static function set_strumlineBackgroundOpacity(value:Int):Int
+  {
+    var save:Save = Save.instance;
+    save.options.strumlineBackgroundOpacity = value;
+    save.flush();
+    return value;
+  }
+
   /**
    * Loads the user's preferences from the save data and apply them.
    */

source/funkin/play/notes/Strumline.hx

@@ -8,6 +8,7 @@ import flixel.group.FlxSpriteGroup.FlxTypedSpriteGroup;
 import flixel.tweens.FlxEase;
 import flixel.tweens.FlxTween;
 import flixel.util.FlxSort;
+import funkin.graphics.FunkinSprite;
 import funkin.play.notes.NoteHoldCover;
 import funkin.play.notes.NoteSplash;
 import funkin.play.notes.NoteSprite;
@@ -85,6 +86,8 @@ class Strumline extends FlxSpriteGroup
 
   public var onNoteIncoming:FlxTypedSignal<NoteSprite->Void>;
 
+  var background:FunkinSprite;
+
   var strumlineNotes:FlxTypedSpriteGroup<StrumlineNote>;
   var noteSplashes:FlxTypedSpriteGroup<NoteSplash>;
   var noteHoldCovers:FlxTypedSpriteGroup<NoteHoldCover>;
@@ -108,6 +111,8 @@ class Strumline extends FlxSpriteGroup
 
   var heldKeys:Array<Bool> = [];
 
+  static final BACKGROUND_PAD:Int = 16;
+
   public function new(noteStyle:NoteStyle, isPlayer:Bool)
   {
     super();
@@ -144,6 +149,13 @@ class Strumline extends FlxSpriteGroup
     this.noteSplashes.zIndex = 50;
     this.add(this.noteSplashes);
 
+    this.background = new FunkinSprite(0, 0).makeSolidColor(Std.int(this.width + BACKGROUND_PAD * 2), FlxG.height, 0xFF000000);
+    // Convert the percent to a number between 0 and 1.
+    this.background.alpha = Preferences.strumlineBackgroundOpacity / 100.0;
+    this.background.scrollFactor.set(0, 0);
+    this.background.x = -BACKGROUND_PAD;
+    this.add(this.background);
+
     this.refresh();
 
     this.onNoteIncoming = new FlxTypedSignal<NoteSprite->Void>();
@@ -168,6 +180,16 @@ class Strumline extends FlxSpriteGroup
     this.active = true;
   }
 
+  override function set_y(value:Float):Float
+  {
+    super.set_y(value);
+
+    // Keep the background on the screen.
+    if (this.background != null) this.background.y = 0;
+
+    return value;
+  }
+
   public function refresh():Void
   {
     sort(SortUtil.byZIndex, FlxSort.ASCENDING);
@@ -978,4 +1000,42 @@ class Strumline extends FlxSpriteGroup
   {
     return FlxSort.byValues(order, a?.strumTime, b?.strumTime);
   }
+
+  override function findMinYHelper()
+  {
+    var value = Math.POSITIVE_INFINITY;
+    for (member in group.members)
+    {
+      if (member == null) continue;
+      // SKIP THE BACKGROUND
+      if (member == this.background) continue;
+
+      var minY:Float;
+      if (member.flixelType == SPRITEGROUP) minY = (cast member : FlxSpriteGroup).findMinY();
+      else
+        minY = member.y;
+
+      if (minY < value) value = minY;
+    }
+    return value;
+  }
+
+  override function findMaxYHelper()
+  {
+    var value = Math.NEGATIVE_INFINITY;
+    for (member in group.members)
+    {
+      if (member == null) continue;
+      // SKIP THE BACKGROUND
+      if (member == this.background) continue;
+
+      var maxY:Float;
+      if (member.flixelType == SPRITEGROUP) maxY = (cast member : FlxSpriteGroup).findMaxY();
+      else
+        maxY = member.y + member.height;
+
+      if (maxY > value) value = maxY;
+    }
+    return value;
+  }
 }

source/funkin/save/Save.hx

@@ -101,6 +101,7 @@ class Save
           zoomCamera: true,
           debugDisplay: false,
           autoPause: true,
+          strumlineBackgroundOpacity: 0,
           inputOffset: 0,
           audioVisualOffset: 0,
           unlockedFramerate: false,
@@ -1349,7 +1350,14 @@ typedef SaveDataOptions =
   var autoPause:Bool;
 
   /**
-   * Offset the user's inputs by this many ms.
+   * If >0, the game will display a semi-opaque background under the notes.
+   * `0` for no background, `100` for solid black if you're freaky like that
+   * @default `0`
+   */
+  var strumlineBackgroundOpacity:Int;
+
+  /**
+   * Offset the users inputs by this many ms.
    * @default `0`
    */
   var inputOffset:Int;

source/funkin/ui/options/PreferencesMenu.hx

@@ -60,6 +60,9 @@ class PreferencesMenu extends Page
     createPrefItemCheckbox('Downscroll', 'Enable to make notes move downwards', function(value:Bool):Void {
       Preferences.downscroll = value;
     }, Preferences.downscroll);
+    createPrefItemPercentage('Strumline Background', 'Give the strumline a semi-transparent background', function(value:Int):Void {
+      Preferences.strumlineBackgroundOpacity = value;
+    }, Preferences.strumlineBackgroundOpacity);
     createPrefItemCheckbox('Flashing Lights', 'Disable to dampen flashing effects', function(value:Bool):Void {
       Preferences.flashingLights = value;
     }, Preferences.flashingLights);