Add caching to IFont2Font

benchmarks/NPOI.Benchmarks/AutoSizeColumnBenchmark.cs

@@ -0,0 +1,57 @@
+using BenchmarkDotNet.Attributes;
+using NPOI.SS.UserModel;
+using NPOI.XSSF.UserModel;
+
+namespace NPOI.Benchmarks;
+
+[MemoryDiagnoser]
+public class AutoSizeColumnBenchmark
+{
+    private static readonly string[] lorem = @"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut 
+labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip 
+ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat 
+nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id 
+est laborum.".Split(' ', '\r', '\n');
+
+    private XSSFWorkbook workbook;
+    private ISheet sheet1;
+
+    [Params(1_000)]
+    public int RowCount { get; set; }
+
+    [Params(5)]
+    public int ColumnCount { get; set; }
+
+    [IterationSetup]
+    public void Setup()
+    {
+        var ipsum = 0;
+
+        workbook = new XSSFWorkbook();
+        sheet1 = workbook.CreateSheet("Sheet1");
+
+        for (var rowNum = 1; rowNum <= RowCount; rowNum++)
+        {
+            var row = sheet1.CreateRow(rowNum);
+            for (int col = 1; col <= ColumnCount; col++)
+            {
+                row.CreateCell(col).SetCellValue(lorem[ipsum++ % lorem.Length]);
+            }
+        }
+    }
+
+    [Benchmark]
+    public void AutoSizeColumn()
+    {
+        for (var col = 1; col <= ColumnCount; col++)
+        {
+            sheet1.AutoSizeColumn(col);
+        }
+    }
+
+    [IterationCleanup]
+    public void Cleanup()
+    {
+        workbook.Dispose();
+    }
+}

main/SS/Util/SheetUtil.cs

@@ -20,6 +20,7 @@ namespace NPOI.SS.Util
     using System;
 
     using NPOI.SS.UserModel;
+    using System.Collections.Concurrent;
     using System.Collections.Generic;
     using SixLabors.Fonts;
     using System.Linq;
@@ -680,9 +681,47 @@ public static bool CanComputeColumnWidth(IFont font)
         //    str.AddAttribute(TextAttribute.SIZE, (float)font.FontHeightInPoints);
         //    if (font.Boldweight == (short)FontBoldWeight.BOLD) str.AddAttribute(TextAttribute.WEIGHT, TextAttribute.WEIGHT_BOLD, startIdx, endIdx);
         //    if (font.IsItalic) str.AddAttribute(TextAttribute.POSTURE, TextAttribute.POSTURE_OBLIQUE, startIdx, endIdx);
-        //    TODO-Fonts: not supported: if (font.Underline == (byte)FontUnderlineType.SINGLE) str.AddAttribute(TextAttribute.UNDERLINE, TextAttribute.UNDERLINE_ON, startIdx, endIdx);           
+        //    TODO-Fonts: not supported: if (font.Underline == (byte)FontUnderlineType.SINGLE) str.AddAttribute(TextAttribute.UNDERLINE, TextAttribute.UNDERLINE_ON, startIdx, endIdx);
         //}
-
+
+        private readonly struct FontCacheKey : IEquatable<FontCacheKey>
+        {
+            public FontCacheKey(string fontName, float fontHeightInPoints, FontStyle style)
+            {
+                FontName = fontName;
+                FontHeightInPoints = fontHeightInPoints;
+                Style = style;
+            }
+
+            public readonly string FontName;
+            public readonly float FontHeightInPoints;
+            public readonly FontStyle Style;
+
+            public bool Equals(FontCacheKey other)
+            {
+                return FontName == other.FontName && FontHeightInPoints.Equals(other.FontHeightInPoints) && Style == other.Style;
+            }
+
+            public override bool Equals(object obj)
+            {
+                return obj is FontCacheKey other && Equals(other);
+            }
+
+            public override int GetHashCode()
+            {
+                unchecked
+                {
+                    var hashCode = FontName != null ? FontName.GetHashCode() : 0;
+                    hashCode = (hashCode * 397) ^ FontHeightInPoints.GetHashCode();
+                    hashCode = (hashCode * 397) ^ (int)Style;
+                    return hashCode;
+                }
+            }
+        }
+
+        private static readonly CultureInfo StartupCulture = CultureInfo.CurrentCulture;
+        private static readonly ConcurrentDictionary<FontCacheKey, Font> FontCache = new();
+
         /// <summary>
         /// Convert HSSFFont to Font.
         /// </summary>
@@ -692,11 +731,6 @@ public static bool CanComputeColumnWidth(IFont font)
         /// found by SixLabors in the current environment.</exception>
         internal static Font IFont2Font(IFont font1)
         {
-            if (SystemFonts.Families == null || SystemFonts.Families.Count() == 0)
-            {
-                throw new FontException("No fonts found installed on the machine.");
-            }
-
             FontStyle style = FontStyle.Regular;
             if (font1.IsBold)
             {
@@ -712,21 +746,39 @@ internal static Font IFont2Font(IFont font1)
             }
             */
 
+            var key = new FontCacheKey(font1.FontName, (float)font1.FontHeightInPoints, style);
+
+            // only use cache if font size is an integer and culture is original to prevent cache size explosion
+            if (font1.FontHeightInPoints == (int) font1.FontHeightInPoints && CultureInfo.CurrentCulture.Equals(StartupCulture))
+            {
+                return FontCache.GetOrAdd(key, IFont2FontImpl);
+            }
+
+            // skip cache
+            return IFont2FontImpl(key);
+        }
+
+        private static Font IFont2FontImpl(FontCacheKey cacheKey)
+        {
             // Try to find font in system fonts. If we can not find out,
             // use "Arial". TODO-Fonts: More fallbacks.
-            SixLabors.Fonts.FontFamily fontFamily;
 
-            if (false == SystemFonts.TryGet(font1.FontName, CultureInfo.CurrentCulture, out fontFamily))
+            if (!SystemFonts.TryGet(cacheKey.FontName, CultureInfo.CurrentCulture, out var fontFamily))
             {
-                if (false == SystemFonts.TryGet("Arial", CultureInfo.CurrentCulture, out fontFamily))
+                if (!SystemFonts.TryGet("Arial", CultureInfo.CurrentCulture, out fontFamily))
                 {
+                    if (!SystemFonts.Families.Any())
+                    {
+                        throw new FontException("No fonts found installed on the machine.");
+                    }
+
                     fontFamily = SystemFonts.Families.First();
                 }
             }
-
-            Font font = new Font(fontFamily, (float)font1.FontHeightInPoints, style);
-            return font;
+
+            return new Font(fontFamily, cacheKey.FontHeightInPoints, cacheKey.Style);
         }
+
         /// <summary>
         /// Check if the cell is in the specified cell range
         /// </summary>