public void TryEnableMicaEffect(FluentAvaloniaTheme thm)
{
// The background colors for the Mica brush are still based around SolidBackgroundFillColorBase resource
// BUT since we can't control the actual Mica brush color, we have to use the window background to create
// the same effect. However, we can't use SolidBackgroundFillColorBase directly since its opaque, and if
// we set the opacity the color become lighter than we want. So we take the normal color, darken it and
// apply the opacity until we get the roughly the correct color
// NOTE that the effect still doesn't look right, but it suffices. Ideally we need access to the Mica
// CompositionBrush to properly change the color but I don't know if we can do that or not
if (thm.RequestedTheme == FluentAvaloniaTheme.DarkModeString)
{
var color = this.TryFindResource("SolidBackgroundFillColorBase", out var value) ? (Color2)(Color)value : new Color2(32, 32, 32);
color = color.LightenPercent(-0.2f);
Background = new ImmutableSolidColorBrush(color, 0.85f);
}
else if (thm.RequestedTheme == FluentAvaloniaTheme.LightModeString)
{
// Similar effect here
var color = this.TryFindResource("SolidBackgroundFillColorBase", out var value) ? (Color2)(Color)value : new Color2(243, 243, 243);
color = color.LightenPercent(0.5f);
Background = new ImmutableSolidColorBrush(color, 0.9);
}
}
private void OnRequestedThemeChanged(FluentAvaloniaTheme sender, RequestedThemeChangedEventArgs args)
{
if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
{
// TODO: add Windows version to CoreWindow
if (IsWindows11 && args.NewTheme != FluentAvaloniaTheme.HighContrastModeString)
{
TryEnableMicaEffect(sender);
}
else if (args.NewTheme == FluentAvaloniaTheme.HighContrastModeString)
{
// Clear the local value here, and let the normal styles take over for HighContrast theme
SetValue(BackgroundProperty, AvaloniaProperty.UnsetValue);
}
}
}
