add controllable leniency

osu.Game.Rulesets.Osu/Edit/Blueprints/Sliders/SliderPlacementBlueprint.cs

@@ -95,6 +95,11 @@ protected override void LoadComplete()
                     bSplineBuilder.CornerThreshold = e.NewValue;
                     Scheduler.AddOnce(updateSliderPathFromBSplineBuilder);
                 }, true);
+
+                freehandToolboxGroup.CircleThreshold.BindValueChanged(e =>
+                {
+                    Scheduler.AddOnce(updateSliderPathFromBSplineBuilder);
+                }, true);
             }
         }
 
@@ -358,7 +363,7 @@ private void updateSliderPathFromBSplineBuilder()
 
         private Vector2[] tryCircleArc(List<Vector2> segment)
         {
-            if (segment.Count < 3) return null;
+            if (segment.Count < 3 || freehandToolboxGroup.CircleThreshold.Value == 0) return null;
 
             // Assume the segment creates a reasonable circular arc and then check if it reasonable
             var points = PathApproximator.BSplineToPiecewiseLinear(segment.ToArray(), bSplineBuilder.Degree);
@@ -412,7 +417,7 @@ private Vector2[] tryCircleArc(List<Vector2> segment)
 
             loss /= points.Count;
 
-            return loss > 0.002 || totalWinding > MathHelper.TwoPi ? null : circleArcControlPoints;
+            return loss > freehandToolboxGroup.CircleThreshold.Value || totalWinding > MathHelper.TwoPi ? null : circleArcControlPoints;
         }
 
         private enum SliderPlacementState

osu.Game.Rulesets.Osu/Edit/FreehandSliderToolboxGroup.cs

@@ -31,6 +31,13 @@ public FreehandSliderToolboxGroup()
             Precision = 0.01f
         };
 
+        public BindableFloat CircleThreshold { get; } = new BindableFloat(0.002f)
+        {
+            MinValue = 0f,
+            MaxValue = 0.005f,
+            Precision = 0.0001f
+        };
+
         // We map internal ranges to a more standard range of values for display to the user.
         private readonly BindableInt displayTolerance = new BindableInt(100)
         {
@@ -44,8 +51,15 @@ public FreehandSliderToolboxGroup()
             MaxValue = 100
         };
 
+        private readonly BindableInt displayCircleThreshold = new BindableInt(40)
+        {
+            MinValue = 0,
+            MaxValue = 100
+        };
+
         private ExpandableSlider<int> toleranceSlider = null!;
         private ExpandableSlider<int> cornerThresholdSlider = null!;
+        private ExpandableSlider<int> circleThresholdSlider = null!;
 
         [BackgroundDependencyLoader]
         private void load()
@@ -59,6 +73,10 @@ private void load()
                 cornerThresholdSlider = new ExpandableSlider<int>
                 {
                     Current = displayCornerThreshold
+                },
+                circleThresholdSlider = new ExpandableSlider<int>
+                {
+                    Current = displayCircleThreshold
                 }
             };
         }
@@ -83,18 +101,32 @@ protected override void LoadComplete()
                 CornerThreshold.Value = displayToInternalCornerThreshold(threshold.NewValue);
             }, true);
 
+            displayCircleThreshold.BindValueChanged(threshold =>
+            {
+                circleThresholdSlider.ContractedLabelText = $"P. C. T.: {threshold.NewValue:N0}";
+                circleThresholdSlider.ExpandedLabelText = $"Perfect Curve Threshold: {threshold.NewValue:N0}";
+
+                CircleThreshold.Value = displayToInternalCircleThreshold(threshold.NewValue);
+            }, true);
+
             Tolerance.BindValueChanged(tolerance =>
                 displayTolerance.Value = internalToDisplayTolerance(tolerance.NewValue)
             );
             CornerThreshold.BindValueChanged(threshold =>
                 displayCornerThreshold.Value = internalToDisplayCornerThreshold(threshold.NewValue)
             );
+            CircleThreshold.BindValueChanged(threshold =>
+                displayCircleThreshold.Value = internalToDisplayCircleThreshold(threshold.NewValue)
+            );
 
             float displayToInternalTolerance(float v) => v / 50f;
             int internalToDisplayTolerance(float v) => (int)Math.Round(v * 50f);
 
             float displayToInternalCornerThreshold(float v) => v / 100f;
             int internalToDisplayCornerThreshold(float v) => (int)Math.Round(v * 100f);
+
+            float displayToInternalCircleThreshold(float v) => v / 20000f;
+            int internalToDisplayCircleThreshold(float v) => (int)Math.Round(v * 20000f);
         }
     }
 }