Avalonia/src/Avalonia.Base/Platform/DefaultPlatformSettings.cs

using System;
using Avalonia.Input;
using Avalonia.Input.Platform;
using Avalonia.Metadata;
using Avalonia.Threading;

namespace Avalonia.Platform
{
    /// <summary>
    /// A default implementation of <see cref="IPlatformSettings"/> for platforms.
    /// </summary>
    [PrivateApi]
    public class DefaultPlatformSettings : IPlatformSettings
    {
        public virtual Size GetTapSize(PointerType type)
        {
            return type switch
            {
                PointerType.Touch or PointerType.Pen => new(10, 10),
                _ => new(4, 4),
            };
        }

        public virtual Size GetDoubleTapSize(PointerType type)
        {
            return type switch
            {
                PointerType.Touch or PointerType.Pen => new(16, 16),
                _ => new(4, 4),
            };
        }

        public virtual TimeSpan GetDoubleTapTime(PointerType type) => TimeSpan.FromMilliseconds(500);

        public virtual TimeSpan HoldWaitDuration => TimeSpan.FromMilliseconds(300);

        public PlatformHotkeyConfiguration HotkeyConfiguration =>
            AvaloniaLocator.Current.GetRequiredService<PlatformHotkeyConfiguration>();

        public virtual PlatformColorValues GetColorValues()
        {
            return new PlatformColorValues
            {
                ThemeVariant = PlatformThemeVariant.Light
            };
        }

        public virtual event EventHandler<PlatformColorValues>? ColorValuesChanged;

        protected virtual void OnColorValuesChanged(PlatformColorValues colorValues)
        {
            Dispatcher.UIThread.Send(
                _ => ColorValuesChanged?.Invoke(this, colorValues));
        }

        public event EventHandler<EventArgs>? TextScalingChanged;

        protected virtual void OnTextScaleChanged() => Dispatcher.UIThread.Send(_ => TextScalingChanged?.Invoke(this, EventArgs.Empty));

        public virtual double GetScaledFontSize(Visual target, double baseFontSize) => baseFontSize;
    }
}