Created LogDecadeMinorTickGenerator

Author: macaba

source/NSD.UI/LogDecadeMinorTickGenerator.cs

@@ -0,0 +1,34 @@
+using ScottPlot;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace NSD.UI
+{
+    public class LogDecadeMinorTickGenerator : IMinorTickGenerator
+    {
+        public int TicksPerDecade { get; set; } = 10;
+
+        public IEnumerable<double> GetMinorTicks(double[] majorPositions, CoordinateRange visibleRange)
+        {
+            var minDecadeTick = double.Floor(visibleRange.Min);
+            var maxDecadeTick = double.Ceiling(visibleRange.Max);
+
+            if(minDecadeTick == maxDecadeTick)
+                return [];
+
+            // pre-calculate the log-distributed offset positions between major ticks
+            IEnumerable<double> minorTickOffsets = Enumerable.Range(1, TicksPerDecade - 1)
+                .Select(x => Math.Log10(x * 10 / TicksPerDecade));
+
+            // iterate major ticks and collect minor ticks with offsets
+            List<double> minorTicks = [];
+            for (double major = minDecadeTick; major <= maxDecadeTick; major += 1)
+            {
+                minorTicks.AddRange(minorTickOffsets.Select(offset => major + offset));
+            }
+
+            return minorTicks;
+        }
+    }
+}

source/NSD.UI/MainWindow.axaml.cs

@@ -324,14 +324,14 @@ private void CommonChartConfig()
             NumericAutomatic xTickGenerator = new()
             {
                 LabelFormatter = logTickLabels,
-                MinorTickGenerator = new LogMinorTickGenerator() { Divisions = 10 },
+                MinorTickGenerator = new LogDecadeMinorTickGenerator() { TicksPerDecade = 10 },
                 IntegerTicksOnly = true,
                 TargetTickCount = 10
             };
             NumericAutomatic yTickGenerator = new()
             {
                 LabelFormatter = logTickLabels,
-                MinorTickGenerator = new LogMinorTickGenerator() { Divisions = 10 },
+                MinorTickGenerator = new LogDecadeMinorTickGenerator() { TicksPerDecade = 10 },
                 IntegerTicksOnly = true,
                 TargetTickCount = 10
             };
@@ -352,9 +352,12 @@ private void CommonChartConfig()
 
         private void SetChartLimitsAndRefresh()
         {
-            var top = Math.Log10(viewModel.YMax + (viewModel.YMax * 0.001));
-            var bottom = Math.Log10(viewModel.YMin - (viewModel.YMin * 0.001));
-            WpfPlot1.Plot.Axes.SetLimits(Math.Log10(viewModel.XMin), Math.Log10(viewModel.XMax), bottom, top);
+            double fudgeFactor = 0.001;
+            var left = Math.Log10(viewModel.XMin - (viewModel.XMin * fudgeFactor));
+            var right = Math.Log10(viewModel.XMax + (viewModel.XMax * fudgeFactor));
+            var top = Math.Log10(viewModel.YMax + (viewModel.YMax * fudgeFactor));
+            var bottom = Math.Log10(viewModel.YMin - (viewModel.YMin * fudgeFactor));
+            WpfPlot1.Plot.Axes.SetLimits(left, right, bottom, top);
             WpfPlot1.Refresh();
         }