protected override void OnElementChanged(VisualElementChangedEventArgs e)
{
base.OnElementChanged(e);
if (e.OldElement == null)
{
if (View.Layer.Sublayers != null)
{
if (View.Layer.Sublayers.Length > 1)
{
View.Layer.Sublayers[0].RemoveFromSuperLayer();
}
}
MyContentPageRenderer page = (MyContentPageRenderer)Element;
if (page.IsGradient)
{
var gradientLayer = new CAGradientLayer();
gradientLayer.Frame = View.Bounds;
gradientLayer.Colors = new CGColor[] { page.StartColor.ToCGColor(), page.EndColor.ToCGColor() };
View.Layer.InsertSublayer(gradientLayer, 0);
}
}
}
private void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
if (e.PropertyName == MyContentPageRenderer.OrientationProperty.PropertyName)
{
if (View.Layer.Sublayers.Length > 1)
{
View.Layer.Sublayers[0].RemoveFromSuperLayer();
}
MyContentPageRenderer page = (MyContentPageRenderer)Element;
if (page.IsGradient)
{
var gradientLayer = new CAGradientLayer();
gradientLayer.Frame = View.Bounds;
gradientLayer.Colors = new CGColor[] { page.StartColor.ToCGColor(), page.EndColor.ToCGColor() };
View.Layer.InsertSublayer(gradientLayer, 0);
}
}
}
protected override void DispatchDraw(Canvas canvas)
{
MyContentPageRenderer myContentPageRenderer = (MyContentPageRenderer)Element;
if (myContentPageRenderer.IsGradient)
{
var gradient = new LinearGradient(0, 0, 0, Height,
myContentPageRenderer.StartColor.ToAndroid(),
myContentPageRenderer.EndColor.ToAndroid(),
Shader.TileMode.Mirror);
var paint = new Paint
{
Dither = true,
};
paint.SetShader(gradient);
canvas.DrawPaint(paint);
}
base.DispatchDraw(canvas);
}
