Plugin Theme Development

Plugin Theme Development

A theme plugin applies a WPF ResourceDictionary that overrides application color keys. The existing shared brushes and controls consume those colors dynamically.

Base default palette

Color key	Default	Purpose
TransparentColor	#00000000	Transparent surfaces
ControlForegroundColor	#FFFFFFFF	General control foreground
WindowBackgroundColor	#101217	Main background
SidebarBackgroundColor	#15181F	Toolbar and sidebar
CardBackgroundColor	#191D25	Cards
CardHoverColor	#202530	Card/list hover
InputBackgroundColor	#11141A	Inputs and inset surfaces
BorderColor	#2A303C	Standard borders
AccentColor	#7C5CFC	Primary accent
AccentHoverColor	#8E72FF	Accent hover
AccentPressedColor	#6748E5	Accent pressed
AccentMutedColor	#2C254E	Muted accent surface
SuccessColor	#35C98A	Online/success
WarningColor	#F4B740	Transitional/warning
InfoColor	#4C8DFF	Information
ErrorColor	#F05D6C	Offline/error/destructive
PrimaryTextColor	#F4F6FA	Primary text
SecondaryTextColor	#A8AFBC	Supporting text
MutedTextColor	#707887	Hints and inactive text
DataGridAlternatingRowColor	#161A22	Alternating rows
DataGridHeaderBackgroundColor	#1B2029	Grid header
DataGridRowHoverColor	#202631	Grid hover

Button/control colors also available:

• SecondaryButtonBackgroundColor, SecondaryButtonHoverColor, SecondaryButtonPressedColor
• SuccessButtonBackgroundColor, SuccessButtonBorderColor, SuccessButtonHoverColor, SuccessButtonHoverBorderColor, SuccessButtonPressedColor, SuccessButtonFocusBorderColor
• DangerButtonBackgroundColor, DangerButtonBorderColor, DangerButtonHoverColor, DangerButtonHoverBorderColor, DangerButtonPressedColor, DangerButtonFocusBorderColor
• TextBoxHoverBorderColor

Override every key for predictable results. Missing keys fall back to whatever dictionary was previously active and can produce a mixed theme.

Brush keys consumed by controls

Each color has a corresponding brush such as WindowBackgroundBrush, CardBackgroundBrush, AccentBrush, SuccessBrush, PrimaryTextBrush, and DataGridAlternatingRowBrush. Theme dictionaries should normally override colors; shared brushes then update automatically.

Theme dictionary example

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Color x:Key="WindowBackgroundColor">#F5F7FA</Color>
  <Color x:Key="SidebarBackgroundColor">#FFFFFF</Color>
  <Color x:Key="CardBackgroundColor">#FFFFFF</Color>
  <Color x:Key="CardHoverColor">#EAF1FB</Color>
  <Color x:Key="InputBackgroundColor">#F1F4F8</Color>
  <Color x:Key="BorderColor">#D7DEE8</Color>
  <Color x:Key="AccentColor">#2167D5</Color>
  <!-- Override the remaining keys as well. -->
</ResourceDictionary>

Embed the XAML as a WPF Page, then apply it:

Uri uri = new("/MyThemePlugin;component/Themes/LightBlue.xaml", UriKind.Relative);
await context.ThemeManager.ApplyResourceDictionaryAsync(Info.PluginIdentifier, uri, cancellationToken);
await context.ThemeManager.SetWindowChromeModeAsync(Info.PluginIdentifier, PluginWindowChromeMode.Light, cancellationToken);

Restore the application theme during disablement:

await context.ThemeManager.RemoveResourceDictionaryAsync(Info.PluginIdentifier, cancellationToken);

The host snapshots and restores replaced resources, but a theme should still remove its dictionary explicitly.

Theme testing checklist

• Main background, toolbar, sidebar, and every card.
• Hover, pressed, selected, disabled, and keyboard-focus states.
• Text boxes, combo boxes, checkboxes, and toggles.
• DataGrid headers, normal rows, alternating rows, selection, and hover.
• Notifications and status badges.
• Manage Receivers, Manage Plugins, Settings, and plugin dialogs.
• Light/dark title bar and window caption buttons.
• Plugin-injected UI using DynamicResource.
• Switching Theme A to Default without restarting.
• Disabling/re-enabling and deleting the theme plugin.