Add markdown preview pane with per-result content types

Flow.Launcher.Infrastructure/UserSettings/Settings.cs

@@ -423,6 +423,12 @@ public DoublePinyinSchemas DoublePinyinSchema
 
         public bool AlwaysPreview { get; set; } = false;
 
+        /// <summary>
+        /// Name of the syntax-highlighting theme used for code blocks in the markdown preview.
+        /// "Auto" follows the app colour scheme (light/dark); otherwise a <see cref="CodeHighlightThemes"/> name.
+        /// </summary>
+        public string CodeHighlightTheme { get; set; } = "Auto";
+
         public bool AlwaysStartEn { get; set; } = false;
 
         private SearchPrecisionScore _querySearchPrecision = SearchPrecisionScore.Regular;
@@ -696,6 +702,15 @@ public enum ColorSchemes
         Dark
     }
 
+    public enum CodeHighlightThemes
+    {
+        Auto,
+        VSCodeLight,
+        VSCodeDarkPlus,
+        CatppuccinMacchiato,
+        OneDark
+    }
+
     public enum SearchWindowScreens
     {
         RememberLastLaunchLocation,

Flow.Launcher.Plugin/Result.cs

@@ -287,6 +287,18 @@ public string PluginDirectory
         /// </summary>
         public PreviewInfo Preview { get; set; } = PreviewInfo.Default;
 
+        /// <summary>
+        /// Controls whether Flow Launcher's preview pane is shown for this result.
+        /// </summary>
+        /// <remarks>
+        /// This is independent of <see cref="PreviewInfo.ContentType"/>, which only decides how the
+        /// preview is rendered. Use this to force the pane open (for example a result whose whole purpose
+        /// is its markdown preview) or to hide it on results that have nothing useful to preview.
+        /// </remarks>
+        /// <default><see cref="Flow.Launcher.Plugin.PreviewVisibility.Default"/></default>
+        [JsonConverter(typeof(JsonStringEnumConverter<PreviewVisibility>))]
+        public PreviewVisibility PreviewVisibility { get; set; } = PreviewVisibility.Default;
+
         /// <summary>
         /// Determines if the user selection count should be added to the score. This can be useful when set to false to allow the result sequence order to be the same everytime instead of changing based on selection.
         /// </summary>
@@ -365,6 +377,7 @@ public Result Clone()
                 ProgressBar = ProgressBar,
                 ProgressBarColor = ProgressBarColor,
                 Preview = Preview,
+                PreviewVisibility = PreviewVisibility,
                 AddSelectedCount = AddSelectedCount,
                 RecordKey = RecordKey,
                 ShowBadge = ShowBadge,
@@ -378,7 +391,7 @@ public Result Clone()
         public record PreviewInfo
         {
             /// <summary>
-            /// Full image used for preview panel
+            /// Shown in the preview panel. Falls back to the result icon when not set. 
             /// </summary>
             public string PreviewImagePath { get; set; } = null;
 
@@ -388,7 +401,8 @@ public record PreviewInfo
             public bool IsMedia { get; set; } = false;
 
             /// <summary>
-            /// Result description text that is shown at the bottom of the preview panel.
+            /// Text shown in the preview panel. How it is displayed depends on
+            /// <see cref="ContentType"/>.
             /// </summary>
             /// <remarks>
             /// When a value is not set, the <see cref="SubTitle"/> will be used.
@@ -406,6 +420,12 @@ public record PreviewInfo
             /// </summary>
             public string FilePath { get; set; } = null;
 
+            /// <summary>
+            /// Controls the preview rendering mode. See <see cref="PreviewContentType"/>.
+            /// </summary>
+            [JsonConverter(typeof(JsonStringEnumConverter<PreviewContentType>))]
+            public PreviewContentType ContentType { get; set; } = PreviewContentType.ImageWithText;
+
             /// <summary>
             /// Default instance of <see cref="PreviewInfo"/>
             /// </summary>
@@ -416,7 +436,52 @@ public record PreviewInfo
                 IsMedia = false,
                 PreviewDelegate = null,
                 FilePath = null,
+                ContentType = PreviewContentType.ImageWithText,
             };
         }
     }
+
+    /// <summary>
+    /// Supported preview description rendering modes.
+    /// </summary>
+    public enum PreviewContentType
+    {
+        /// <summary>
+        /// Shows the preview image above the result title, with the description
+        /// rendered as plain text below a separator.
+        /// </summary>
+        [JsonStringEnumMemberName("imageWithText")]
+        ImageWithText,
+
+        /// <summary>
+        /// Shows a scrollable panel with the description rendered as formatted markdown.
+        /// </summary>
+        [JsonStringEnumMemberName("markdown")]
+        Markdown,
+    }
+
+    /// <summary>
+    /// Controls whether the preview pane is shown for a <see cref="Result"/>.
+    /// </summary>
+    public enum PreviewVisibility
+    {
+        /// <summary>
+        /// Follow Flow Launcher's normal preview behaviour (the global "Always Preview" setting and the
+        /// user's manual preview toggle decide whether the pane is shown).
+        /// </summary>
+        [JsonStringEnumMemberName("default")]
+        Default,
+
+        /// <summary>
+        /// Never show the preview pane for this result, even when the global "Always Preview" setting is on.
+        /// </summary>
+        [JsonStringEnumMemberName("never")]
+        Never,
+
+        /// <summary>
+        /// Always show the preview pane for this result, even when the global "Always Preview" setting is off.
+        /// </summary>
+        [JsonStringEnumMemberName("always")]
+        Always,
+    }
 }

Flow.Launcher.Test/CodeHighlightThemeTest.cs

@@ -0,0 +1,58 @@
+using Flow.Launcher.Resources.Controls;
+using NUnit.Framework;
+using NUnit.Framework.Legacy;
+
+namespace Flow.Launcher.Test
+{
+    [TestFixture]
+    internal class CodeHighlightThemeTest
+    {
+        private string _savedThemeName;
+
+        [SetUp]
+        public void SetUp() => _savedThemeName = PreviewMarkdownScrollViewer.ActiveThemeName;
+
+        [TearDown]
+        public void TearDown() => PreviewMarkdownScrollViewer.ApplyCodeHighlightTheme(_savedThemeName, isDark: true);
+
+        [Test]
+        public void GivenAutoSetting_WhenAppIsDark_ThenActiveThemeIsADarkTheme()
+        {
+            PreviewMarkdownScrollViewer.ApplyCodeHighlightTheme("Auto", isDark: true);
+
+            ClassicAssert.AreEqual("VS Code Dark+", PreviewMarkdownScrollViewer.ActiveThemeName);
+        }
+
+        [Test]
+        public void GivenAutoSetting_WhenAppIsLight_ThenActiveThemeIsALightTheme()
+        {
+            PreviewMarkdownScrollViewer.ApplyCodeHighlightTheme("Auto", isDark: false);
+
+            ClassicAssert.AreEqual("VS Code Light", PreviewMarkdownScrollViewer.ActiveThemeName);
+        }
+
+        [Test]
+        public void GivenExplicitTheme_WhenApplied_ThenActiveThemeMatchesRegardlessOfAppScheme()
+        {
+            PreviewMarkdownScrollViewer.ApplyCodeHighlightTheme("OneDark", isDark: false);
+
+            ClassicAssert.AreEqual("One Dark", PreviewMarkdownScrollViewer.ActiveThemeName);
+        }
+
+        [Test]
+        public void GivenEmptySetting_WhenApplied_ThenFallsBackToAutoBehaviour()
+        {
+            PreviewMarkdownScrollViewer.ApplyCodeHighlightTheme("", isDark: false);
+
+            ClassicAssert.AreEqual("VS Code Light", PreviewMarkdownScrollViewer.ActiveThemeName);
+        }
+
+        [Test]
+        public void GivenUnrecognisedSetting_WhenApplied_ThenFallsBackToAutoBehaviour()
+        {
+            PreviewMarkdownScrollViewer.ApplyCodeHighlightTheme("BogusTheme", isDark: true);
+
+            ClassicAssert.AreEqual("VS Code Dark+", PreviewMarkdownScrollViewer.ActiveThemeName);
+        }
+    }
+}