dvWithPageScrollbars function

ThemeData dvWithPageScrollbars(ThemeData theme)

theme with every page's scrollbar always on screen.

The always-visible defaults used to live only in dartvelDefaultTheme, so an application that brought its own theme got Flutter's: a thumb that shows while scrolling and fades away. Visibility and dragging are forced; the application's own thickness, radius and colours are kept, and Dartvel's quiet ones fill whatever it did not set.

Implementation

ThemeData dvWithPageScrollbars(ThemeData theme) {
  final ScrollbarThemeData own = theme.scrollbarTheme;
  final ScrollbarThemeData fallback = dartvelDefaultTheme(theme.brightness, fontPackage: null).scrollbarTheme;
  return theme.copyWith(
    scrollbarTheme: own.copyWith(
      thumbVisibility: WidgetStateProperty.all(true),
      trackVisibility: WidgetStateProperty.all(true),
      interactive: true,
      thickness: own.thickness ?? fallback.thickness,
      radius: own.radius ?? fallback.radius,
      thumbColor: own.thumbColor ?? fallback.thumbColor,
      trackColor: own.trackColor ?? fallback.trackColor,
      trackBorderColor: own.trackBorderColor ?? fallback.trackBorderColor,
    ),
  );
}