Allow setting of the font and font size used in the text viewer (#1930)

* Allow setting of the font and font size used in the text viewer

* Refactor font settings initialization

* Clamp TextViewer font size from Settings

---------

Co-authored-by: ema <mccoy39082@163.com>

OPTIONS.md

@@ -237,6 +237,20 @@ These keys are also stored in `QuickLook.config`.
 - Example:
   - `<AllowDarkTheme>True</AllowDarkTheme>`
 
+### `<FontFamily>`
+- Default: default font of the current language
+- Type: `String`
+- Description: Allow setting of the font used in the text viewer.
+- Example:
+  - `<FontFamily>Cascadia Mono SemiLight</FontFamily>`
+
+### `<FontSize>`
+- Default: 14.0
+- Type: `Double`
+- Description: Allow setting of font size used in the text viewer.
+- Example:
+  - `<FontSize>13</FontSize>`
+
 ## Notes
 
 - All option names are case-sensitive and stored as XML element names under `<Settings>`.

QuickLook.Plugin/QuickLook.Plugin.TextViewer/TextViewerPanel.cs

@@ -72,7 +72,6 @@ public partial class TextViewerPanel : TextEditor, IDisposable
 
     public TextViewerPanel()
     {
-        FontSize = 14;
         ShowLineNumbers = true;
         WordWrap = true;
         IsReadOnly = true;
@@ -117,8 +116,13 @@ public partial class TextViewerPanel : TextEditor, IDisposable
 
         PreviewMouseWheel += Viewer_MouseWheel;
 
-        FontFamily = new FontFamily(TranslationHelper.Get("Editor_FontFamily",
-            domain: Assembly.GetExecutingAssembly().GetName().Name));
+        // Read configured font size and validate it to avoid negative or unreasonable values
+        FontSize = Math.Max(1d, Math.Min(72d, SettingHelper.Get("FontSize", 14d, "QuickLook.Plugin.TextViewer")));
+        FontFamily = new FontFamily(
+            SettingHelper.Get("FontFamily",
+                failsafe: TranslationHelper.Get("Editor_FontFamily",
+                domain: Assembly.GetExecutingAssembly().GetName().Name),
+            "QuickLook.Plugin.TextViewer"));
 
         // Add a custom element generator (e.g., to truncate extremely long lines).
         TextArea.TextView.ElementGenerators.Add(new TruncateLongLines());