[FileExplorer][SVG preview] Swap order of default and svg namespace if default comes first (#18825)

* [FileExplorer Add-ons][SVG preview] Swap order of default and svg namespace if default comes first

Inkscape v1.1 swapped order of default and svg namespaces in svg file (default first, svg after).
That resulted in parser being unable to parse it correctly and instead of svg, text was previewed.
MS Edge and Firefox also couldn't preview svg files with mentioned order of namespaces definitions.

* expect.txt

* Update comment

* Minor fixes

* Use full namespace definition instead of prefix

.github/actions/spell-check/expect.txt

@@ -616,6 +616,7 @@ Filterx
 finalizer
 findfast
 findstr
+Firefox
 FIXEDFILEINFO
 FLASHZONES
 FLASHZONESONQUICKSWITCH
@@ -886,6 +887,7 @@ ingbuffer
 inheritdoc
 INITDIALOG
 initguid
+Inkscape
 Inlines
 inorder
 INotification

src/modules/previewpane/SvgPreviewHandler/SvgPreviewControl.cs

@@ -102,6 +102,10 @@ namespace Microsoft.PowerToys.PreviewHandler.Svg
 
             try
             {
+                // Fixes #17527 - Inkscape v1.1 swapped order of default and svg namespaces in svg file (default first, svg after).
+                // That resulted in parser being unable to parse it correctly and instead of svg, text was previewed.
+                // MS Edge and Firefox also couldn't preview svg files with mentioned order of namespaces definitions.
+                svgData = SvgPreviewHandlerHelper.SwapNamespaces(svgData);
                 svgData = SvgPreviewHandlerHelper.AddStyleSVG(svgData);
             }
             catch (Exception ex)

src/modules/previewpane/common/Utilities/SvgPreviewHandlerHelper.cs

@@ -4,6 +4,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.Linq;
 using System.Xml.Linq;
 
@@ -154,6 +155,29 @@ namespace Common.Utilities
             return length + "px";
         }
 
+        /// <summary>
+        /// Swaps positions of default and svg namespace definitions if default namespace comes first in original SVG data
+        /// </summary>
+        /// <param name="svgData">SVG data</param>
+        /// <returns>Returns modified SVG data</returns>
+        public static string SwapNamespaces(string svgData)
+        {
+            const string defaultNamespace = "xmlns=\"http://www.w3.org/2000/svg\"";
+            const string svgNamespace = "xmlns:svg=\"http://www.w3.org/2000/svg\"";
+
+            int defaultNamespaceIndex = svgData.IndexOf(defaultNamespace, StringComparison.InvariantCultureIgnoreCase);
+            int svgNamespaceIndex = svgData.IndexOf(svgNamespace, StringComparison.InvariantCultureIgnoreCase);
+
+            if (defaultNamespaceIndex != -1 && svgNamespaceIndex != -1 && defaultNamespaceIndex < svgNamespaceIndex)
+            {
+                svgData = svgData.Replace(defaultNamespace, "{0}", StringComparison.InvariantCultureIgnoreCase);
+                svgData = svgData.Replace(svgNamespace, "{1}", StringComparison.InvariantCultureIgnoreCase);
+                svgData = string.Format(CultureInfo.InvariantCulture, svgData, svgNamespace, defaultNamespace);
+            }
+
+            return svgData;
+        }
+
         /// <summary>
         /// Remove a CSS unit from the end of the string
         /// </summary>