Implement skinning for slider border thickness (#4471)

Implement skinning for slider border thickness

Co-authored-by: Dean Herbert <pe@ppy.sh>

osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSlider.cs

@@ -160,6 +160,7 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
         {
             base.SkinChanged(skin, allowFallback);
 
+            Body.BorderSize = skin.GetValue<SkinConfiguration, float?>(s => s.SliderBorderSize) ?? SliderBody.DEFAULT_BORDER_SIZE;
             Body.AccentColour = skin.GetValue<SkinConfiguration, Color4?>(s => s.CustomColours.ContainsKey("SliderTrackOverride") ? s.CustomColours["SliderTrackOverride"] : (Color4?)null) ?? AccentColour;
             Body.BorderColour = skin.GetValue<SkinConfiguration, Color4?>(s => s.CustomColours.ContainsKey("SliderBorder") ? s.CustomColours["SliderBorder"] : (Color4?)null) ?? Color4.White;
             Ball.AccentColour = skin.GetValue<SkinConfiguration, Color4?>(s => s.CustomColours.ContainsKey("SliderBall") ? s.CustomColours["SliderBall"] : (Color4?)null) ?? AccentColour;

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/SliderBody.cs

@@ -14,6 +14,8 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
 {
     public abstract class SliderBody : CompositeDrawable
     {
+        public const float DEFAULT_BORDER_SIZE = 1;
+
         private readonly SliderPath path;
         protected Path Path => path;
 
@@ -64,6 +66,23 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
             }
         }
 
+        /// <summary>
+        /// Used to size the path border.
+        /// </summary>
+        public float BorderSize
+        {
+            get => path.BorderSize;
+            set
+            {
+                if (path.BorderSize == value)
+                    return;
+
+                path.BorderSize = value;
+
+                container.ForceRedraw();
+            }
+        }
+
         public Quad PathDrawQuad => container.ScreenSpaceDrawQuad;
 
         protected SliderBody()
@@ -92,6 +111,9 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
 
         private class SliderPath : SmoothPath
         {
+            private const float border_max_size = 8f;
+            private const float border_min_size = 0f;
+
             private const float border_portion = 0.128f;
             private const float gradient_portion = 1 - border_portion;
 
@@ -130,12 +152,33 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
                 }
             }
 
+            private float borderSize = DEFAULT_BORDER_SIZE;
+
+            public float BorderSize
+            {
+                get => borderSize;
+                set
+                {
+                    if (borderSize == value)
+                        return;
+
+                    if (value < border_min_size || value > border_max_size)
+                        return;
+
+                    borderSize = value;
+
+                    InvalidateTexture();
+                }
+            }
+
+            private float calculatedBorderPortion => BorderSize * border_portion;
+
             protected override Color4 ColourAt(float position)
             {
-                if (position <= border_portion)
+                if (calculatedBorderPortion != 0f && position <= calculatedBorderPortion)
                     return BorderColour;
 
-                position -= border_portion;
+                position -= calculatedBorderPortion;
                 return new Color4(AccentColour.R, AccentColour.G, AccentColour.B, (opacity_at_edge - (opacity_at_edge - opacity_at_centre) * position / gradient_portion) * AccentColour.A);
             }
         }

osu.Game/Skinning/LegacySkinDecoder.cs

@@ -34,6 +34,10 @@ namespace osu.Game.Skinning
                         case @"CursorExpand":
                             skin.CursorExpand = pair.Value != "0";
                             break;
+
+                        case @"SliderBorderSize":
+                            skin.SliderBorderSize = Parsing.ParseFloat(pair.Value);
+                            break;
                     }
 
                     break;

osu.Game/Skinning/SkinConfiguration.cs

@@ -25,6 +25,8 @@ namespace osu.Game.Skinning
 
         public int HitCircleOverlap { get; set; }
 
+        public float? SliderBorderSize { get; set; }
+
         public bool? CursorExpand { get; set; } = true;
     }
 }