Made the zip compression parametric.

README.md

@@ -80,11 +80,13 @@ The output is like:
 
 The `XlsxWriter` class is the entry point for almost all functionality of the library. It is designed so that most of its methods can be chained to write the Excel file using a fluent syntax.\
 Please note that an `XlsxWriter` object **must be disposed** to properly finalize the Excel file. Sandwitching its lifetime in a `using` statement is recommended.\
-Pass the constructor a writeable `Stream` to save the Excel file into.
+Pass the constructor a writeable `Stream` to save the Excel file into, and optionally the desired compression level of the underlying zip stream. The default `CompressionLevel.Level3` roughly matches file sizes produced by Excel.
 
 ```csharp
 // class XlsxWriter
-public XlsxWriter(Stream stream);
+public XlsxWriter(
+    Stream stream,
+    SharpCompress.Compressors.Deflate.CompressionLevel compressionLevel = CompressionLevel.Level3);
 ```
 
 The recipe is adding a worksheet with `BeginWorksheet`, adding a row with `BeginRow`, writing cells to that row with `Write`, and repeating as required. Rows and worksheets are implicitly finalized as soon as new rows or worksheets are added, or the `XlsxWriter` is disposed.

examples/Examples/Large.cs

@@ -1,8 +1,35 @@
-using System;
+/*
+LargeXlsx - Minimalistic .net library to write large XLSX files
+
+Copyright 2020-2021 Salvatore ISAJA. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice,
+this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+this list of conditions and the following disclaimer in the documentation
+and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED THE COPYRIGHT HOLDER ``AS IS'' AND ANY EXPRESS
+OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
+NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY DIRECT,
+INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+using System;
 using System.Diagnostics;
 using System.Drawing;
 using System.IO;
 using LargeXlsx;
+using SharpCompress.Compressors.Deflate;
 
 namespace Examples
 {
@@ -15,7 +42,7 @@ public static void Run()
         {
             var stopwatch = Stopwatch.StartNew();
             using (var stream = new FileStream($"{nameof(Large)}.xlsx", FileMode.Create, FileAccess.Write))
-            using (var xlsxWriter = new XlsxWriter(stream))
+            using (var xlsxWriter = new XlsxWriter(stream, CompressionLevel.Level3))
             {
                 var whiteFont = new XlsxFont("Calibri", 11, Color.White, bold: true);
                 var blueFill = new XlsxFill(Color.FromArgb(0, 0x45, 0x86));

examples/Examples/StyledLarge.cs

@@ -1,7 +1,7 @@
 /*
 LargeXlsx - Minimalistic .net library to write large XLSX files
 
-Copyright 2020 Salvatore ISAJA. All rights reserved.
+Copyright 2020-2021 Salvatore ISAJA. All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:
@@ -30,6 +30,7 @@ OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
 using System.IO;
 using System.Linq;
 using LargeXlsx;
+using SharpCompress.Compressors.Deflate;
 
 namespace Examples
 {
@@ -44,7 +45,7 @@ public static void Run()
             var rnd = new Random();
             var stopwatch = Stopwatch.StartNew();
             using (var stream = new FileStream($"{nameof(StyledLarge)}.xlsx", FileMode.Create, FileAccess.Write))
-            using (var xlsxWriter = new XlsxWriter(stream))
+            using (var xlsxWriter = new XlsxWriter(stream, CompressionLevel.Level3))
             {
                 var headerStyle = new XlsxStyle(
                     new XlsxFont("Calibri", 11, Color.White, bold: true),

src/LargeXlsx/XlsxWriter.cs

@@ -1,7 +1,7 @@
 /*
 LargeXlsx - Minimalistic .net library to write large XLSX files
 
-Copyright 2020 Salvatore ISAJA. All rights reserved.
+Copyright 2020-2021 Salvatore ISAJA. All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:
@@ -30,6 +30,7 @@ OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
 using System.Linq;
 using System.Text;
 using SharpCompress.Common;
+using SharpCompress.Compressors.Deflate;
 using SharpCompress.Writers;
 using SharpCompress.Writers.Zip;
 
@@ -51,13 +52,13 @@ public class XlsxWriter : IDisposable
         public string GetRelativeColumnName(int offsetFromCurrentColumn) => Util.GetColumnName(CurrentColumnNumber + offsetFromCurrentColumn);
         public static string GetColumnName(int columnIndex) => Util.GetColumnName(columnIndex);
 
-        public XlsxWriter(Stream stream)
+        public XlsxWriter(Stream stream, CompressionLevel compressionLevel = CompressionLevel.Level3)
         {
             _worksheets = new List<Worksheet>();
             _stylesheet = new Stylesheet();
             DefaultStyle = XlsxStyle.Default;
 
-            _zipWriter = (ZipWriter)WriterFactory.Open(stream, ArchiveType.Zip, new ZipWriterOptions(CompressionType.Deflate));
+            _zipWriter = (ZipWriter)WriterFactory.Open(stream, ArchiveType.Zip, new ZipWriterOptions(CompressionType.Deflate) { DeflateCompressionLevel = compressionLevel });
         }
 
         public void Dispose()