Support .properties

QuickLook.Plugin/QuickLook.Plugin.TextViewer/Themes/HighlightingDefinitions/Light/PropertiesHighlightingDefinition.cs

@@ -0,0 +1,65 @@
+using ICSharpCode.AvalonEdit.Document;
+using ICSharpCode.AvalonEdit.Highlighting;
+using ICSharpCode.AvalonEdit.Rendering;
+using System.Collections.Generic;
+using System.Text.RegularExpressions;
+using System.Windows;
+using System.Windows.Media;
+
+namespace QuickLook.Plugin.TextViewer.Themes.HighlightingDefinitions.Light;
+
+public class PropertiesHighlightingDefinition : LightHighlightingDefinition
+{
+    public override string Name => "Properties";
+
+    public override string Extension => ".properties";
+
+    public override HighlightingRuleSet MainRuleSet => new()
+    {
+        Rules =
+        {
+            new HighlightingRule
+            {
+                Regex = new Regex(@"#.*", RegexOptions.Compiled),
+                Color = GetNamedColor("Comment")
+            }
+        }
+    };
+
+    public override HighlightingColor GetNamedColor(string name)
+    {
+        return name switch
+        {
+            "Comment" => new HighlightingColor
+            {
+                Name = "Comment",
+                Foreground = new SimpleHighlightingBrush(Colors.Green),
+            },
+            _ => null
+        };
+    }
+
+    public override IEnumerable<HighlightingColor> NamedHighlightingColors =>
+    [
+        GetNamedColor("Comment")
+    ];
+
+    public override DocumentColorizingTransformer[] LineTransformers { get; } = [new KeyHighlighter()];
+
+    public class KeyHighlighter : DocumentColorizingTransformer
+    {
+        protected override void ColorizeLine(DocumentLine line)
+        {
+            var text = CurrentContext.Document.GetText(line);
+            int idx = text.IndexOf('=');
+            if (idx > 0)
+            {
+                ChangeLinePart(
+                    line.Offset,
+                    line.Offset + idx,
+                    el => el.TextRunProperties.SetForegroundBrush(Colors.Blue.ToBrush())
+                );
+            }
+        }
+    }
+}