added updates to fix issue #234

Demo/Program.cs

@@ -85,10 +85,27 @@ static void Main(string[] args)
             TestGetText();
             TestMarkdownReader();
             TestRecompressJBIG2();
+            TestIssue234();
 
             return;
         }
 
+        static void TestIssue234()
+        {
+            Console.WriteLine("\n=== TestIssue234 =======================");
+
+            var pix = new Pixmap("../../../TestDocuments/Image/boxedpage.jpg"); // 629x1000 image
+            var scaled = new Pixmap(pix, 943, 1500, null); // scale up
+            byte[] jpeg = scaled.ToBytes("jpg", 65);
+
+            using var doc = new Document();
+            Page page = doc.NewPage(0, 943, 1500);
+            page.InsertImage(page.Rect, stream: jpeg);
+            page.Dispose();
+            doc.Save("issue_234.pdf");
+            doc.Close();
+        }
+
         static void TestRecompressJBIG2()
         {
             Console.WriteLine("\n=== TestJBIG2 =======================");

MuPDF.NET.Test/UtilsTest.cs

@@ -0,0 +1,50 @@
+using NUnit.Framework;
+using MuPDF.NET;
+
+namespace MuPDF.NET.Test
+{
+    public class UtilsTest
+    {
+        [Test]
+        public void FloatToString_NoScientificNotation()
+        {
+            Assert.That(Utils.FloatToString(1.5f), Is.EqualTo("1.5"));
+            Assert.That(Utils.FloatToString(0f), Is.EqualTo("0"));
+            Assert.That(Utils.FloatToString(-123.456f), Is.EqualTo("-123.456"));
+            Assert.That(Utils.FloatToString(1000000f), Is.EqualTo("1000000"));
+
+            // Values that would use scientific notation with default ToString
+            string small = Utils.FloatToString(0.0000123f);
+            Assert.That(small.Contains("E") || small.Contains("e"), Is.False, "Should not use scientific notation");
+            Assert.That(small.Contains("0.00001") || small.Contains("0.000012"), Is.True);
+        }
+
+        [Test]
+        public void FloatToString_InvariantCulture()
+        {
+            string result = Utils.FloatToString(1.5f);
+            Assert.That(result.Contains("."), Is.True);
+            Assert.That(result.Contains(","), Is.False);
+        }
+
+        [Test]
+        public void DoubleToString_NoScientificNotation()
+        {
+            Assert.That(Utils.DoubleToString(1.5), Is.EqualTo("1.5"));
+            Assert.That(Utils.DoubleToString(0), Is.EqualTo("0"));
+            Assert.That(Utils.DoubleToString(-123.456), Is.EqualTo("-123.456"));
+            Assert.That(Utils.DoubleToString(1000000), Is.EqualTo("1000000"));
+
+            string small = Utils.DoubleToString(1.23e-10);
+            Assert.That(small.Contains("E") || small.Contains("e"), Is.False, "Should not use scientific notation");
+        }
+
+        [Test]
+        public void DoubleToString_InvariantCulture()
+        {
+            string result = Utils.DoubleToString(1.5);
+            Assert.That(result.Contains("."), Is.True);
+            Assert.That(result.Contains(","), Is.False);
+        }
+    }
+}

MuPDF.NET/Page.cs

@@ -2242,7 +2242,15 @@ public int InsertImage(
                 xobject.pdf_dict_puts(imgName, ref_);
                 FzBuffer nres = mupdf.mupdf.fz_new_buffer(50);
                 nres.fz_append_string(
-                    string.Format(System.Globalization.CultureInfo.InvariantCulture, template, mat.a, mat.b, mat.c, mat.d, mat.e, mat.f, imgName)
+                    string.Format(System.Globalization.CultureInfo.InvariantCulture,
+                    template,
+                    Utils.FloatToString(mat.a),
+                    Utils.FloatToString(mat.b),
+                    Utils.FloatToString(mat.c),
+                    Utils.FloatToString(mat.d),
+                    Utils.FloatToString(mat.e),
+                    Utils.FloatToString(mat.f),
+                    imgName)
                 );
                 Utils.InsertContents(pageDoc, page.obj(), nres, overlay);
             }

MuPDF.NET/Utils.cs

@@ -7913,19 +7913,19 @@ internal static void SetDotCultureForNumber()
         }
 
         /// <summary>
-        /// Converts a float to string with dot as decimal separator, regardless of culture
+        /// Converts a float to string with dot as decimal separator, without scientific notation.
         /// </summary>
-        internal static string FloatToString(float value)
+        public static string FloatToString(float value)
         {
-            return value.ToString(CultureInfo.InvariantCulture);
+            return value.ToString("0.#######", CultureInfo.InvariantCulture);
         }
 
         /// <summary>
-        /// Converts a double to string with dot as decimal separator, regardless of culture
+        /// Converts a double to string with dot as decimal separator, without scientific notation.
         /// </summary>
-        internal static string DoubleToString(double value)
+        public static string DoubleToString(double value)
         {
-            return value.ToString(CultureInfo.InvariantCulture);
+            return value.ToString("0.#################", CultureInfo.InvariantCulture);
         }
 
         /// <summary>