/// <summary>
/// Memoizer with one parameter (kept as weak reference), used to perform a lazy-cached evaluation. (see http://en.wikipedia.org/wiki/Memoization)
/// </summary>
/// <typeparam name="TParam">The return type to memoize</typeparam>
/// <param name="func">the function to evaluate</param>
/// <returns>A memoized value</returns>
public static Func <TParam, TResult> AsWeakLockedMemoized <TParam, TResult>(this Func <TParam, TResult> func)
where TParam : class
{
var values = new WeakAttachedDictionary <TParam, string>();
return(v => values.GetValue(v, "value", () => func(v)));
}
private static bool GetNeedsKeyboard(UIView view)
{
var superViews = view.FindSuperviews().ToList();
superViews.Insert(0, view);
return(superViews.Any(superView => _attachedProperties.GetValue(superView, NeedsKeyboardAttachedPropertyKey, () => default(bool?)).GetValueOrDefault()));
}
public static TRenderer GetRenderer <TElement, TRenderer>(this TElement element, Func <TRenderer> rendererFactory)
where TElement : DependencyObject
{
return(_renderers.GetValue(element, typeof(TRenderer), rendererFactory));
}
private static bool GetNeedsKeyboard(UIView view)
{
return(view != null && _attachedProperties.GetValue(view, NeedsKeyboardAttachedPropertyKey, () => default(bool?)).GetValueOrDefault());
}
internal static void SetForeground(this UIElement element, object localValue)
{
var brushSubscription = _imageBrushSubscription.GetValue(element, "foreground", () => new SerialDisposable());
brushSubscription.Disposable = null;
switch (localValue)
{
case SolidColorBrush scb:
element.SetStyle("color", scb.ColorWithOpacity.ToHexString());
break;
case GradientBrush gradient:
element.SetStyle(
("background", gradient.ToCssString(element.RenderSize)),
("color", "transparent"),
("background-clip", "text")
);
break;
case ImageBrush imageBrush:
brushSubscription.Disposable = imageBrush.Subscribe(img =>
{
switch (img.Kind)
{
case ImageDataKind.Empty:
case ImageDataKind.Error:
element.ResetStyle(
"background-color",
"background-image",
"background-size");
element.SetStyle(
("color", "transparent"),
("background-clip", "text"));
break;
case ImageDataKind.DataUri:
case ImageDataKind.Url:
default:
element.SetStyle(
("color", "transparent"),
("background-clip", "text"),
("background-color", ""),
("background-origin", "content-box"),
("background-position", imageBrush.ToCssPosition()),
("background-size", imageBrush.ToCssBackgroundSize()),
("background-image", "url(" + img.Value + ")")
);
break;
}
});
break;
case AcrylicBrush acrylic:
acrylic.Apply(element);
element.SetStyle("background-clip", "text");
break;
case UnsetValue uv:
// TODO: support other foreground types
default:
element.ResetStyle("color", "background", "background-clip");
AcrylicBrush.ResetStyle(element);
break;
}
}