Add support for moving the cursor

src/Spectre.Console/Internal/Ratio.cs

@@ -0,0 +1,75 @@
+// Ported from Rich by Will McGugan, licensed under MIT.
+// https://github.com/willmcgugan/rich/blob/527475837ebbfc427530b3ee0d4d0741d2d0fc6d/rich/_ratio.py
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+
+namespace Spectre.Console.Internal
+{
+    internal static class Ratio
+    {
+        public static List<int> Reduce(int total, List<int> ratios, List<int> maximums, List<int> values)
+        {
+            ratios = ratios.Zip(maximums, (a, b) => (ratio: a, max: b)).Select(a => a.max > 0 ? a.ratio : 0).ToList();
+            var totalRatio = ratios.Sum();
+            if (totalRatio <= 0)
+            {
+                return values;
+            }
+
+            var totalRemaining = total;
+            var result = new List<int>();
+
+            foreach (var (ratio, maximum, value) in ratios.Zip(maximums, values))
+            {
+                if (ratio != 0 && totalRatio > 0)
+                {
+                    var distributed = (int)Math.Min(maximum, Math.Round((double)(ratio * totalRemaining / totalRatio)));
+                    result.Add(value - distributed);
+                    totalRemaining -= distributed;
+                    totalRatio -= ratio;
+                }
+                else
+                {
+                    result.Add(value);
+                }
+            }
+
+            return result;
+        }
+
+        public static List<int> Distribute(int total, List<int> ratios, List<int>? minimums = null)
+        {
+            if (minimums != null)
+            {
+                ratios = ratios.Zip(minimums, (a, b) => (ratio: a, min: b)).Select(a => a.min > 0 ? a.ratio : 0).ToList();
+            }
+
+            var totalRatio = ratios.Sum();
+            Debug.Assert(totalRatio > 0, "Sum or ratios must be > 0");
+
+            var totalRemaining = total;
+            var distributedTotal = new List<int>();
+
+            if (minimums == null)
+            {
+                minimums = ratios.Select(_ => 0).ToList();
+            }
+
+            foreach (var (ratio, minimum) in ratios.Zip(minimums, (a, b) => (a, b)))
+            {
+                var distributed = (totalRatio > 0)
+                    ? Math.Max(minimum, (int)Math.Ceiling(ratio * totalRemaining / (double)totalRatio))
+                    : totalRemaining;
+
+                distributedTotal.Add(distributed);
+                totalRatio -= ratio;
+                totalRemaining -= distributed;
+            }
+
+            return distributedTotal;
+        }
+    }
+}