code-editor-theme.md

WPF ILSpy: How decompiled code + hover tooltip theme is determined

1. Where the selected theme comes from

1. SessionSettings.Theme is loaded from session XML, defaulting to ThemeManager.Current.DefaultTheme ("Light").
   • ProjectRover/src/ILSpy/ILSpy/SessionSettings.cs:58
   • ProjectRover/src/ILSpy/ILSpy/Themes/ThemeManager.cs:50
2. On app startup, ILSpy applies it with ThemeManager.Current.Theme = sessionSettings.Theme.
   • ProjectRover/src/ILSpy/ILSpy/App.xaml.cs:112
3. ThemeManager.UpdateTheme() loads /themes/Theme.{ThemeName}.xaml, merges it into app resources, and caches all SyntaxColor.* entries for syntax highlighting.
   • ProjectRover/src/ILSpy/ILSpy/Themes/ThemeManager.cs:113
   • ProjectRover/src/ILSpy/ILSpy/Themes/ThemeManager.cs:128
   • ProjectRover/src/ILSpy/ILSpy/Themes/ThemeManager.cs:136

Theme can be changed at runtime from:

• View menu theme picker (SetThemeCommand writes SessionSettings.Theme)
  • ProjectRover/src/ILSpy/ILSpy/Controls/MainMenu.xaml:25
  • ProjectRover/src/ILSpy/ILSpy/Commands/SetThemeCommand.cs:14
• Options panel combo box (bound to SessionSettings.Theme)
  • ProjectRover/src/ILSpy/ILSpy/Options/DisplaySettingsPanel.xaml:14

ThemeManager listens for SessionSettings.Theme property changes and reapplies the theme dictionary:

• ProjectRover/src/ILSpy/ILSpy/Themes/ThemeManager.cs:211

2. Decompiled source editor theme resolution

1. Editor base brushes are dynamic resources in DecompilerTextView.xaml:
   • Background: themes:ResourceKeys.TextBackgroundBrush
   • Foreground: themes:ResourceKeys.TextForegroundBrush
   • Line numbers: themes:ResourceKeys.LineNumbersForegroundBrush
   • ProjectRover/src/ILSpy/ILSpy/TextView/DecompilerTextView.xaml:35
2. These keys are defined in Theme.*.xaml (and merged with Base.*.xaml):
   • Example light: ProjectRover/src/ILSpy/ILSpy/Themes/Theme.Light.xaml:8
   • Example dark: ProjectRover/src/ILSpy/ILSpy/Themes/Theme.Dark.xaml:8
3. Syntax highlighting definitions are registered in DecompilerTextView.RegisterHighlighting().
   • ProjectRover/src/ILSpy/ILSpy/TextView/DecompilerTextView.cs:1318
4. While registering each .xshd, ILSpy wraps definition creation with ThemeManager.Current.ApplyHighlightingColors(highlightingDefinition).
   • ProjectRover/src/ILSpy/ILSpy/TextView/DecompilerTextView.cs:1457
5. ApplyHighlightingColors() resets named colors and applies matching SyntaxColor.<Language>.* entries from the current theme dictionary.
   • ProjectRover/src/ILSpy/ILSpy/Themes/ThemeManager.cs:90
   • ProjectRover/src/ILSpy/ILSpy/Themes/ThemeManager.cs:98
6. Active language picks a highlighting definition by file extension (Language.SyntaxHighlighting), and decompile output sets it on the editor (textEditor.SyntaxHighlighting = highlighting).
   • ProjectRover/src/ILSpy/ILSpy/Languages/Language.cs:76
   • ProjectRover/src/ILSpy/ILSpy/TextView/DecompilerTextView.cs:746
7. AvalonEdit colorization uses ThemeAwareHighlightingColorizer; for non-theme-aware definitions on dark themes, it auto-adjusts colors.
   • ProjectRover/src/ILSpy/ILSpy/TextView/DecompilerTextEditor.cs:9
   • ProjectRover/src/ILSpy/ILSpy/TextView/ThemeAwareHighlightingColorizer.cs:24

When theme changes, ILSpy forces re-register + redraw of decompiled output:

• DecompilerTextView.RegisterHighlighting(); RefreshDecompiledView();
• ProjectRover/src/ILSpy/ILSpy/AssemblyTree/AssemblyTreeModel.cs:89

3. Hover tooltip popup theme resolution

1. On mouse hover, DecompilerTextView finds the hovered reference segment and calls GenerateTooltip(...).
   • ProjectRover/src/ILSpy/ILSpy/TextView/DecompilerTextView.cs:237
   • ProjectRover/src/ILSpy/ILSpy/TextView/DecompilerTextView.cs:412
2. For opcode/entity tooltips, ILSpy builds a FlowDocument via DocumentationUIBuilder, passing languageService.Language.SyntaxHighlighting / currentLanguage.SyntaxHighlighting.
   • ProjectRover/src/ILSpy/ILSpy/TextView/DecompilerTextView.cs:419
   • ProjectRover/src/ILSpy/ILSpy/TextView/DecompilerTextView.cs:471
3. DocumentationUIBuilder uses that highlighting definition for signature/code blocks (DocumentHighlighter + rich text runs).
   • ProjectRover/src/ILSpy/ILSpy/TextView/DocumentationUIBuilder.cs:96
   • ProjectRover/src/ILSpy/ILSpy/TextView/DocumentationUIBuilder.cs:110
4. Popup chrome/text colors are SystemColors-based:
   • Background: SystemColors.ControlBrushKey
   • Border: SystemColors.ControlDarkBrushKey
   • Foreground: SystemColors.InfoTextBrushKey
   • ProjectRover/src/ILSpy/ILSpy/TextView/DecompilerTextView.cs:523
5. Those SystemColors.* resources are overridden by the active base theme dictionaries (Base.Light.xaml / Base.Dark.xaml), so popup container text/chrome follows current theme.
   • ProjectRover/src/ILSpy/ILSpy/Themes/Base.Light.xaml:18
   • ProjectRover/src/ILSpy/ILSpy/Themes/Base.Dark.xaml:18

4. Short summary

• Decompiled editor colors come from:
  • ResourceKeys brushes (background/foreground/etc.) from Theme.*.xaml
  • Syntax token colors from SyntaxColor.* entries applied through ThemeManager.ApplyHighlightingColors()
• Hover popup colors come from:
  • Same language syntax highlighting for code/signatures inside the tooltip
  • SystemColors.* brushes for popup frame/text, which are overridden by the active base theme resources

5. Avalonia (Rover) equivalent: current implementation

5.1 Theme selection + persistence

1. Rover still uses SessionSettings.Theme and applies it at startup:
   • ProjectRover/src/ProjectRover/App.axaml.cs:77
   • ProjectRover/src/ProjectRover/App.axaml.cs:295
2. Avalonia theme switching is centralized in ThemeManagerShim (ThemeManager in Rover), and it drives RequestedThemeVariant on app/windows:
   • ProjectRover/src/ProjectRover/Themes/ThemeManagerShim.cs:80
   • ProjectRover/src/ProjectRover/Themes/ThemeManagerShim.cs:93
   • ProjectRover/src/ProjectRover/Themes/ThemeManagerShim.cs:101
3. Options panel and menu are wired to the same setting/theme manager:
   • ProjectRover/src/ProjectRover/Options/DisplaySettingsPanel.axaml:18
   • ProjectRover/src/ProjectRover/Commands/ThemeCommands.cs:38
   • ProjectRover/src/ProjectRover/Controls/MainMenu.axaml.cs:1403

5.2 Decompiled editor colors

1. Highlighting registration flow is equivalent to WPF (RegisterHighlighting + ApplyHighlightingColors hook):
   • ProjectRover/src/ProjectRover/TextView/DecompilerTextView.axaml.cs:1759
   • ProjectRover/src/ProjectRover/TextView/DecompilerTextView.axaml.cs:1923
2. Decompile output still assigns language highlighting definition to editor:
   • ProjectRover/src/ProjectRover/TextView/DecompilerTextView.axaml.cs:1111
3. Decompiled syntax coloring is now driven by ILSpy highlighting + ThemeManager.ApplyHighlightingColors (WPF-equivalent), not TextMate theme names.
4. Current/line/link editor resources are still bound from theme resource keys:
   • ProjectRover/src/ProjectRover/TextView/DecompilerTextView.axaml.cs:327

5.3 Hover tooltip colors

1. Hover flow mirrors WPF: resolve reference segment, build tooltip content via DocumentationUIBuilder, show popup:
   • ProjectRover/src/ProjectRover/TextView/DecompilerTextView.axaml.cs:743
   • ProjectRover/src/ProjectRover/TextView/DecompilerTextView.axaml.cs:752
   • ProjectRover/src/ProjectRover/TextView/DecompilerTextView.axaml.cs:820
2. Popup styling uses resource keys ToolTipBackgroundBrush/ToolTipBorderBrush with hardcoded fallback:
   • ProjectRover/src/ProjectRover/Controls/TooltipPopup.cs:93
   • ProjectRover/src/ProjectRover/Controls/TooltipPopup.cs:94
3. App-level theme resources are currently provided via ThemeDictionaries for only Light and Dark:
   • ProjectRover/src/ProjectRover/App.axaml:67
   • ProjectRover/src/ProjectRover/App.axaml:176

6. Rover status update: 6 themes now wired

Target names (same as WPF) are now available in Rover:

• Light
• Dark
• VS Code Light+
• VS Code Dark+
• R# Light
• R# Dark

Implemented:

1. Theme surface/API expanded to 6 names (no 2-theme collapsing)
   • ProjectRover/src/ProjectRover/Themes/ThemeManagerShim.cs:22
   • ProjectRover/src/ProjectRover/Themes/ThemeManagerShim.cs:31
   • ProjectRover/src/ProjectRover/Themes/ThemeManagerShim.cs:168
2. Menu commands now include all 6 theme entries
   • ProjectRover/src/ProjectRover/Commands/ThemeCommands.cs:78
3. View-model theme picker now exposes all 6
   • ProjectRover/src/ProjectRover/MainWindowViewModel.cs:67
4. Per-theme Avalonia resource dictionaries added and loaded dynamically
   • ProjectRover/src/ProjectRover/Themes/ThemeManagerShim.cs:190
   • ProjectRover/src/ProjectRover/Themes/Theme.VSCodeLightPlus.axaml:1
   • ProjectRover/src/ProjectRover/Themes/Theme.VSCodeDarkPlus.axaml:1
   • ProjectRover/src/ProjectRover/Themes/Theme.RSharpLight.axaml:1
   • ProjectRover/src/ProjectRover/Themes/Theme.RSharpDark.axaml:1
5. Tooltip resource keys now exist in both app-level and per-theme resources
   • ProjectRover/src/ProjectRover/App.axaml:87
   • ProjectRover/src/ProjectRover/App.axaml:198
   • ProjectRover/src/ProjectRover/Controls/TooltipPopup.cs:93
6. Decompiler TextMate wiring removed to keep decompiled highlighting source aligned with WPF (SyntaxColor.* via theme manager).
   • ProjectRover/src/ProjectRover/TextView/DecompilerTextView.axaml.cs

7. Syntax color parity status (updated)

SyntaxColor.* support is now implemented in Rover:

1. Rover stores SyntaxColor.<Language>.* entries directly in Rover Theme.*.axaml files as themes:SyntaxColorResource (no WPF theme file dependency).
   • ProjectRover/src/ProjectRover/Themes/Theme.Light.axaml
   • ProjectRover/src/ProjectRover/Themes/Theme.Dark.axaml
   • ProjectRover/src/ProjectRover/Themes/Theme.VSCodeLightPlus.axaml
   • ProjectRover/src/ProjectRover/Themes/Theme.VSCodeDarkPlus.axaml
   • ProjectRover/src/ProjectRover/Themes/Theme.RSharpLight.axaml
   • ProjectRover/src/ProjectRover/Themes/Theme.RSharpDark.axaml
2. ThemeManagerShim now caches parsed syntax-color mappings per selected theme and applies them to named highlighting colors (same prefix logic as WPF).
   • ProjectRover/src/ProjectRover/Themes/ThemeManagerShim.cs
3. Highlighting refresh is triggered for open editors when theme changes.
   • ProjectRover/src/ProjectRover/Themes/ThemeManagerShim.cs
   • ProjectRover/src/ProjectRover/TextView/DecompilerTextView.axaml.cs:1778
4. A dark-theme fallback conversion path remains in place only when syntax-color mappings cannot be loaded/applied.

8. Remaining gaps to full WPF parity

1. Visual equivalence still needs manual tuning/verification for each of the 6 themes across editor + tooltip scenarios.
2. Decompiler no longer blends SyntaxColor.* with TextMate theme tokenization; remaining differences are mostly brush/value tuning and Avalonia rendering differences.
3. No automated UI regression check yet validates token colors for all languages/themes.