Add path-based SVG rendering with RLE encoding to reduce file size and memory usage (#655)

* Optimize SVGs

* Apply suggestion from coderabbit

* Use invariant culture

* fix

* Update

* Fix

* Add test for new method

* Add tests

* Final comment updates

* update

* update comment

* Convert to regular string

* Add invariant culture formatting methods for StringBuilder appends

* Update AppendInvariant method to use G7 precision for float formatting

* Update ToStr method to use G7 precision for float formatting

Author: Shane32

QRCoder/Extensions/StringExtensions.cs

@@ -55,4 +55,48 @@ internal static byte[] HexColorToByteArray(this string colorString)
     internal static string ToString(this char c, CultureInfo _)
         => c.ToString();
 #endif
+
+    /// <summary>
+    /// Appends an integer value to the StringBuilder using invariant culture formatting.
+    /// </summary>
+    /// <param name="sb">The StringBuilder to append to.</param>
+    /// <param name="num">The integer value to append.</param>
+    internal static void AppendInvariant(this StringBuilder sb, int num)
+    {
+#if NET6_0_OR_GREATER
+        sb.Append(CultureInfo.InvariantCulture, $"{num}");
+#else
+#if HAS_SPAN
+        Span<char> buffer = stackalloc char[16];
+        if (num.TryFormat(buffer, out int charsWritten, default, CultureInfo.InvariantCulture))
+        {
+            sb.Append(buffer.Slice(0, charsWritten));
+            return;
+        }
+#endif
+        sb.Append(num.ToString(CultureInfo.InvariantCulture));
+#endif
+    }
+
+    /// <summary>
+    /// Appends a float value to the StringBuilder using invariant culture formatting with G7 precision.
+    /// </summary>
+    /// <param name="sb">The StringBuilder to append to.</param>
+    /// <param name="num">The float value to append.</param>
+    internal static void AppendInvariant(this StringBuilder sb, float num)
+    {
+#if NET6_0_OR_GREATER
+        sb.Append(CultureInfo.InvariantCulture, $"{num:G7}");
+#else
+#if HAS_SPAN
+        Span<char> buffer = stackalloc char[16];
+        if (num.TryFormat(buffer, out int charsWritten, "G7", CultureInfo.InvariantCulture))
+        {
+            sb.Append(buffer.Slice(0, charsWritten));
+            return;
+        }
+#endif
+        sb.Append(num.ToString("G7", CultureInfo.InvariantCulture));
+#endif
+    }
 }

QRCoder/PdfByteQRCode.cs

@@ -204,11 +204,11 @@ private string CreatePathFromModules()
 
                 // Create a single rectangle for the entire run of dark modules
                 // Format: x y width height re
-                pathCommands.Append(ToStr(startX));
+                pathCommands.AppendInvariant(startX);
                 pathCommands.Append(' ');
-                pathCommands.Append(ToStr(y));
+                pathCommands.AppendInvariant(y);
                 pathCommands.Append(' ');
-                pathCommands.Append(ToStr(x - startX));
+                pathCommands.AppendInvariant(x - startX);
                 pathCommands.Append(" 1 re\r\n");
             }
         }
@@ -242,11 +242,11 @@ private static string ColorToPdfRgb(byte[] color)
     private static string ToStr(int value) => value.ToString(CultureInfo.InvariantCulture);
 
     /// <summary>
-    /// Converts an integer to a string using invariant culture for consistent PDF formatting.
+    /// Converts a float to a string using invariant culture for consistent PDF formatting.
     /// </summary>
-    /// <param name="value">The integer value to convert.</param>
-    /// <returns>String representation of the integer.</returns>
-    private static string ToStr(float value) => value.ToString("0.######", CultureInfo.InvariantCulture);
+    /// <param name="value">The float value to convert.</param>
+    /// <returns>String representation of the float.</returns>
+    private static string ToStr(float value) => value.ToString("G7", CultureInfo.InvariantCulture);
 }
 
 /// <summary>

QRCoder/SvgQRCode.cs

@@ -952,6 +952,7 @@ namespace QRCoder
     {
         public SvgQRCode() { }
         public SvgQRCode(QRCoder.QRCodeData data) { }
+        public string GetGraphic() { }
         public string GetGraphic(int pixelsPerModule) { }
         public string GetGraphic(System.Drawing.Size viewBox, bool drawQuietZones = true, QRCoder.SvgQRCode.SizingMode sizingMode = 0, QRCoder.SvgQRCode.SvgLogo? logo = null) { }
         public string GetGraphic(System.Drawing.Size viewBox, System.Drawing.Color darkColor, System.Drawing.Color lightColor, bool drawQuietZones = true, QRCoder.SvgQRCode.SizingMode sizingMode = 0, QRCoder.SvgQRCode.SvgLogo? logo = null) { }

QRCoderApiTests/net35+net40+net50+netstandard20+netstandard21/QRCoder.approved.txt

@@ -959,6 +959,7 @@ namespace QRCoder
     {
         public SvgQRCode() { }
         public SvgQRCode(QRCoder.QRCodeData data) { }
+        public string GetGraphic() { }
         public string GetGraphic(int pixelsPerModule) { }
         public string GetGraphic(System.Drawing.Size viewBox, bool drawQuietZones = true, QRCoder.SvgQRCode.SizingMode sizingMode = 0, QRCoder.SvgQRCode.SvgLogo? logo = null) { }
         public string GetGraphic(System.Drawing.Size viewBox, System.Drawing.Color darkColor, System.Drawing.Color lightColor, bool drawQuietZones = true, QRCoder.SvgQRCode.SizingMode sizingMode = 0, QRCoder.SvgQRCode.SvgLogo? logo = null) { }