/// <summary>
/// Adds a gradient layer as a background layer to a view.
/// </summary>
/// <param name="view">The view to add the gradient to.</param>
/// <param name="gradient">A gradient layer.</param>
/// <param name="index">The index to insert the gradient layer (default=0)</param>
public static void AddGradientBackground(this UIView view, CAGradientLayer gradient, int index = 0, bool animate = false)
{
gradient.Frame = view.Bounds;
gradient.MasksToBounds = true;
CAGradientLayer existingGradient = null;
if (view.Layer.Sublayers != null)
{
foreach (var l in view.Layer.Sublayers)
{
if (l.GetType() == typeof(CAGradientLayer))
{
existingGradient = (CAGradientLayer)l;
break;
}
}
}
view.Layer.InsertSublayer(gradient, index);
gradient.Opacity = animate ? 0 : 1;
if (existingGradient != null)
{
existingGradient.Opacity = 1;
view.Layer.InsertSublayer(gradient, index + 1);
if (animate)
{
// Create fade in animation for the new gradient
var fadein = CABasicAnimation.FromKeyPath("opacity");
fadein.SetTo(NSNumber.FromFloat(1));
fadein.Duration = .5;
fadein.AutoReverses = false;
fadein.RemovedOnCompletion = false;
fadein.FillMode = CAFillMode.Forwards;
// Create fade out animation for the existing gradient
var fadeout = CABasicAnimation.FromKeyPath("opacity");
fadeout.SetTo(NSNumber.FromFloat(0));
fadeout.Duration = .5;
fadeout.AutoReverses = false;
fadeout.RemovedOnCompletion = false;
fadeout.FillMode = CAFillMode.Forwards;
fadeout.AnimationStopped += (sender, e) =>
{
existingGradient.RemoveFromSuperLayer();
};
// Execute the animations.
gradient.AddAnimation(fadein, "opacityIN");
existingGradient.AddAnimation(fadeout, "opacityOUT");
}
else
{
existingGradient.RemoveFromSuperLayer();
}
}
}
public override void Draw(CGRect rect)
{
base.Draw(rect);
if (Element.ShadowType == ShadowType.None)
{
_gradientLayer?.RemoveFromSuperLayer();
return;
}
if (Element.ShadowType == ShadowType.AcrylicTop)
{
_gradientLayer?.RemoveFromSuperLayer();
NativeView.Layer.BackgroundColor = new CGColor(1, 1, 1);
return;
}
if (NativeView.Layer.Sublayers != null &&
NativeView.Layer.Sublayers.Length > 0 &&
NativeView.Layer.Sublayers[0] is CAGradientLayer)
{
return;
}
var gradientsPoints = ComputationHelper.RadiusGradientToPoints(180);
// Top shadow
var startColor = Color.FromHex("30000000");
var endColor = Color.FromHex("00ffffff");
if (Element.ShadowType == ShadowType.Bottom)
{
var tmpColor = startColor;
startColor = endColor;
endColor = tmpColor;
}
_gradientLayer = new CAGradientLayer
{
Frame = rect,
StartPoint = gradientsPoints.StartPoint.ToPointF(),
EndPoint = gradientsPoints.EndPoint.ToPointF(),
Colors = new[]
{
startColor.ToCGColor(),
endColor.ToCGColor(),
},
};
NativeView.Layer.InsertSublayer(_gradientLayer, 0);
_previousSize = Bounds.Size;
}
protected override void OnDetached()
{
if (gradLayer != null)
{
gradLayer.RemoveFromSuperLayer();
}
}
protected override void OnFillChanged(Brush newValue)
{
base.OnFillChanged(newValue);
if (_gradientLayer != null)
{
_gradientLayer.RemoveFromSuperLayer();
_gradientLayer = null;
}
_rectangleLayer.FillColor = _Color.Clear.CGColor;
var scbFill = newValue as SolidColorBrush;
var lgbFill = newValue as LinearGradientBrush;
if (scbFill != null)
{
_fillSubscription.Disposable =
Brush.AssignAndObserveBrush(scbFill, c => _rectangleLayer.FillColor = c);
}
else if (lgbFill != null)
{
_gradientLayer = lgbFill.GetLayer(Frame.Size);
Layer.InsertSublayer(_gradientLayer, 0); // We want the _gradientLayer to be below the _rectangleLayer (which contains the stroke)
}
InvalidateMeasure();
}
public override void RemoveFromSuperview()
{
base.RemoveFromSuperview();
_gradient.RemoveAllAnimations();
_gradient.RemoveFromSuperLayer();
}
protected override void Dispose(bool disposing)
{
if (TextColor != null)
{
TextColor.Dispose();
TextColor = null;
}
if (HighlightColor != null)
{
HighlightColor.Dispose();
HighlightColor = null;
}
if (ButtonTintColor != null)
{
ButtonTintColor.Dispose();
ButtonTintColor = null;
}
if (_HighlightLayer != null)
{
_HighlightLayer.RemoveFromSuperLayer();
_HighlightLayer.Dispose();
}
if (Font != null)
{
Font.Dispose();
}
base.Dispose(disposing);
}
private void CreateGradient()
{
gradientLayer?.RemoveFromSuperLayer();
var button = Element as Button;
var uiButton = Control as UIButton;
if (uiButton.Frame.Width == 0 || uiButton.Frame.Height == 0)
{
return;
}
var topColor = button.BackgroundColor;
var bottomColor = ButtonGradientEffect.GetGradientColor(button);
gradientLayer = Gradient.GetGradientLayer(topColor.ToCGColor(), bottomColor.ToCGColor(), uiButton.Frame.Width, uiButton.Frame.Height);
Control.Layer.InsertSublayer(gradientLayer, 0);
}
void SetGradient()
{
gradLayer?.RemoveFromSuperLayer();
var xfButton = Element as Button;
var colorTop = xfButton.BackgroundColor;
var colorBottom = ButtonGradientEffect.GetGradientColor(xfButton);
gradLayer = Gradient.GetGradientLayer(colorTop.ToCGColor(), colorBottom.ToCGColor(), (float)xfButton.Width, (float)xfButton.Height);
Control.Layer.InsertSublayer(gradLayer, 0);
}
protected override void OnDetached()
{
if (_visualElement != null)
{
_visualElement.SizeChanged -= OnSizeChanged;
}
if (_view != null)
{
_view.ClipsToBounds = _clipsToBounds;
}
_layer?.RemoveFromSuperLayer();
_layer?.Dispose();
_layer = null;
_view = null;
_visualElement = null;
System.Diagnostics.Debug.WriteLine($"Detached {GetType().Name} from {Element.GetType().FullName}");
}
private void DrawBackground()
{
try
{
_gradientLayer?.RemoveFromSuperLayer();
if (!Element.BackgroundGradientColorFrom.HasValue ||
!Element.BackgroundGradientColorTo.HasValue)
{
return;
}
var startColor = Element.BackgroundGradientColorFrom.GetValueOrDefault().ToCGColor();
var endColor = Element.BackgroundGradientColorTo.GetValueOrDefault().ToCGColor();
var startX = .5;
var startY = 0.0;
var endX = .5;
var endY = 1.0;
if (Element.IsHorizontalGradientBackground)
{
startX = 0;
startY = .5;
endX = 1;
endY = .5;
}
_gradientLayer = new CAGradientLayer
{
StartPoint = new CGPoint(startX, startY),
EndPoint = new CGPoint(endX, endY),
Frame = UIScreen.MainScreen.Bounds, // used it instead of rect
Colors = new CGColor[]
{
startColor,
endColor
}
};
NativeView.Layer.InsertSublayer(_gradientLayer, 0);
}
catch (Exception ex)
{
Debug.WriteLine(ex);
}
}
/// <summary>
/// Removes the layer from view.
/// </summary>
/// <param name="view">View.</param>
public static void RemoveLayerFromView(UIView view)
{
CAGradientLayer layerToRemove = null;
foreach (CALayer aLayer in view.Layer.Sublayers)
{
if (aLayer is CAGradientLayer)
{
layerToRemove = (CAGradientLayer)aLayer;
}
}
if (layerToRemove != null)
{
layerToRemove.RemoveFromSuperLayer();
}
}
protected override void OnDetached()
{
gradLayer?.RemoveFromSuperLayer();
}
