TThemeManager

Central theme management component. Manages color palettes and component style definitions. Notifies IThemeSubscriber components when theme changes.

CoreThemeObserver Pattern

Overview

TThemeManager is a non-visual component that manages application theming. Components implementing IThemeSubscriber can subscribe to receive automatic style updates when the theme changes.

Key Properties

Property	Type	Description
Palette	`TThemePalette`	Current color palette with primary, secondary, background, text colors.
StyleDefs	`TObjectDictionary`	Component-specific style definitions keyed by component type.

TThemePalette

Property	Type	Description
PrimaryColor	`STRING`	Primary brand color (hex).
SecondaryColor	`STRING`	Secondary accent color.
PrimaryBackground	`STRING`	Main background color.
SecondaryBackground	`STRING`	Secondary/card background.
PrimaryText	`STRING`	Main text color.
SecondaryText	`STRING`	Muted/secondary text.
BorderColor	`STRING`	Default border color.

Key Methods

PROCEDURE Subscribe(Subscriber: IThemeSubscriber);

Registers a component to receive theme updates.

PROCEDURE Unsubscribe(Subscriber: IThemeSubscriber);

Removes a component from receiving theme updates.

PROCEDURE NotifySubscribers;

Broadcasts current theme to all subscribers. Called automatically when theme changes.

FUNCTION GetStyleDef(ComponentType: STRING): TComponentStyleDef;

Returns style definition for a specific component type (e.g., 'button', 'card', 'header').

IThemeSubscriber Interface

IThemeSubscriber = INTERFACE
   PROCEDURE ApplyThemeStyles(ThemeManager: TThemeManager);
   FUNCTION GetSubscriberComponentType: STRING;
END;

Usage Pattern

// In component's Loaded method:
ThemeManagerInstance := FindThemeManager(Self);
IF Assigned(ThemeManagerInstance) THEN
   ThemeManagerInstance.Subscribe(Self);

// In component's ApplyThemeStyles:
PROCEDURE TMyCard.ApplyThemeStyles(ThemeManager: TThemeManager);
VAR
   CardStyle: TComponentStyleDef;
BEGIN
   CardStyle := ThemeManager.GetStyleDef('card');
   IF Assigned(CardStyle) THEN
      TDom.SetStyle(ElementHandle, 'background-color', CardStyle.BackgroundColor);
END;

FindThemeManager: Use the helper function FindThemeManager(Self) to locate the ThemeManager in the component hierarchy. It searches up through parent components.