ScottPlot.Tools.Pad() to pad arrays with data on each side #255

dev/changelog.md

@@ -25,6 +25,10 @@ _ScottPlot uses [semantic](https://semver.org/) (major.minor.patch) versioning.
   * Create a GDI rendering module which uses System.Drawing 
   * Create a SkiaSharp rendering module and user control (supporting OpenGL hardware acceleration)
 
+## ScottPlot 4.0.29 (in development)
+* `DataGen.Range()` now has `includeStop` argument to include the last value in the returned array.
+* `Tools.Pad()` has been created to return a copy of a given array padded with data values on each side. (#255) _Thanks @ckovamees_
+
 ## ScottPlot 4.0.28
 * `Ticks()` now has arguments for numericStringFormat (X and Y) to make it easy to customize formatting of tick labels (percentage, currency, scientific notation, etc.) using standard [numeric format strings](https://docs.microsoft.com/en-us/dotnet/standard/base-types/standard-numeric-format-strings). Example use is demonstrated in the cookbook. (#336) _Thanks @deiruch_
 * The right-click menu can now be more easily customized by writing a custom menu to `FormsPlot.ContextMenuStrip` or `WpfPlot.ContextMenu`. Demonstrations of both are in the demo application. (#337) _Thanks @Antracik_

src/ScottPlot/Tools.cs

@@ -280,5 +280,29 @@ public static double[] Round(double[] data, int decimals = 2)
                 rounded[i] = Math.Round(data[i], decimals);
             return rounded;
         }
+
+        /// <summary>
+        /// return a copy of the given array padded with the given value at both sidees
+        /// </summary>
+        public static double[] Pad(double[] values, int padCount = 1, double padWithLeft = 0, double padWithRight = 0, bool cloneEdges = false)
+        {
+            double[] padded = new double[values.Length + padCount * 2];
+
+            Array.Copy(values, 0, padded, padCount, values.Length);
+
+            if (cloneEdges)
+            {
+                padWithLeft = values[0];
+                padWithRight = values[values.Length - 1];
+            }
+
+            for (int i = 0; i < padCount; i++)
+            {
+                padded[i] = padWithLeft;
+                padded[padded.Length - 1 - i] = padWithRight;
+            }
+
+            return padded;
+        }
     }
 }

tests/Tools/Pad.cs

@@ -0,0 +1,37 @@
+using NUnit.Framework;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace ScottPlotTests.Tools
+{
+    class Pad
+    {
+        [Test]
+        public void Test_Pad_NoArguments()
+        {
+            double[] values = { 1, 2, 3 };
+            double[] result = ScottPlot.Tools.Pad(values);
+
+            Assert.AreEqual(new double[] { 0, 1, 2, 3, 0 }, result);
+        }
+
+        [Test]
+        public void Test_Pad_MultipleDefined()
+        {
+            double[] values = { 1, 2, 3 };
+            double[] result = ScottPlot.Tools.Pad(values, 3, -1, -2);
+
+            Assert.AreEqual(new double[] { -1, -1, -1, 1, 2, 3, -2, -2, -2 }, result);
+        }
+
+        [Test]
+        public void Test_Pad_CloneEdges()
+        {
+            double[] values = { 1, 2, 3 };
+            double[] result = ScottPlot.Tools.Pad(values, 3, cloneEdges: true);
+
+            Assert.AreEqual(new double[] { 1, 1, 1, 1, 2, 3, 3, 3, 3 }, result);
+        }
+    }
+}