转一个orbitpanel GIS

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Windows.Foundation;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

namespace App8
{
    public class orbitpanel:Panel
    {
        int i = 0;
        public int orbitsnunber
        {
            get { return (int)GetValue(OrbitsProperty); }
            set { SetValue(OrbitsProperty,value); }
        }
        public static readonly DependencyProperty OrbitsProperty = DependencyProperty.Register("orbitsnunber", typeof(int), typeof(orbitpanel), new PropertyMetadata(1, OnOrbitsChanged));
        private static void OnOrbitsChanged(DependencyObject d,DependencyPropertyChangedEventArgs e)
{

if ((int)e.NewValue < 1)
{
throw new ArgumentException(
"Orbits must be greater than or equal to 1.");
}
}
        public static int GetOrbit(DependencyObject obj)
        {
            return (int)obj.GetValue(OrbitProperty);
        }
        public static void SetOrbit(DependencyObject obj, int value)
        {
            obj.SetValue(OrbitProperty, value);
        }
        public static readonly DependencyProperty OrbitProperty =DependencyProperty.RegisterAttached("Orbit",
typeof(int),
typeof(orbitpanel),
new PropertyMetadata(0));
        protected override Size MeasureOverride(Size availableSize)
        {
            var sortedItems = SortElements();
            double max = 0.0;
            foreach (List<UIElement> orbitItems in sortedItems)
            {
                if (orbitItems.Count > 0)
                {
                    foreach (UIElement element in orbitItems)
                    {
                        element.Measure(availableSize);
                        if (element.DesiredSize.Width > max)
                            max = element.DesiredSize.Width;
                        if (element.DesiredSize.Height > max)
                            max = element.DesiredSize.Height;
                    }
                }
            }
            Size desiredSize = new Size(max * orbitsnunber * 2, max * orbitsnunber * 2);
            if (double.IsInfinity(availableSize.Height) ||
            double.IsInfinity(availableSize.Width))
                return desiredSize;
            else
                return availableSize;

        }
        protected override Size ArrangeOverride(Size finalSize)
        {
            var sortedItems = SortElements();
            double orbitSpacing = CalculateOrbitSpacing(finalSize);
            foreach (List<UIElement> orbitItems in sortedItems)
            {
                int count = orbitItems.Count;
                if (count > 0)
                {
                    double circumference = 2 * Math.PI * orbitSpacing * (i + 1);
                    double slotSize = Math.Min(orbitSpacing, circumference / count);
                    double maxSize = Math.Min(orbitSpacing, slotSize);
                    double angleIncrement = 360 / count;
                    double currentAngle = 0;
                    Point centerPoint =
                    new Point(finalSize.Width / 2, finalSize.Height / 2);
                    foreach (UIElement element in orbitItems)
                    {
                        double angle = Math.PI / 180 * (currentAngle - 90);
                        double left = orbitSpacing * (i + 1) * Math.Cos(angle);
                        double top = orbitSpacing * (i + 1) * Math.Sin(angle);
                        Rect finalRect = new Rect(
                        centerPoint.X + left - element.DesiredSize.Width / 2,
                        centerPoint.Y + top - element.DesiredSize.Height / 2,
                        element.DesiredSize.Width,
                        element.DesiredSize.Height);
                        element.Arrange(finalRect);
                        currentAngle += angleIncrement;
                    }
                }
            }
            return base.ArrangeOverride(finalSize);
        }
        private List<UIElement>[] SortElements()
        {
            var list = new List<UIElement>[orbitsnunber];
            for (int i = 0; i < orbitsnunber; i++)
            {
                if (i == orbitsnunber - 1)
                    list[i] = (from UIElement child in Children
                               where GetOrbit(child) >= i
                               select child).ToList<UIElement>();
                else
                    list[i] = (from UIElement child in Children
                               where GetOrbit(child) == i
                               select child).ToList<UIElement>();
            }
            return list;
        }
        private double CalculateOrbitSpacing(Size availableSize)
        {
            double constrainingSize = Math.Min(
            availableSize.Width, availableSize.Height);
            double space = constrainingSize / 2;
            return space / orbitsnunber;
        }
    }
}
使用方法

 <local:orbitpanel orbitsnunber="1">
            <Image x:Name="image"  local:orbitpanel.Orbit="0"   HorizontalAlignment="Left" Height="166" PointerEntered="image_PointerEntered_1" PointerExited="image_PointerExited_1"  Margin="449,349,0,0" VerticalAlignment="Top" Width="261" Source="http://img.trip.elong.com/guide/attachments/bc/d1/be/bcd1bef731bbde7796bb55edbed0fc1f.jpg" RenderTransformOrigin="0.5,0.5">               
            </Image>      
        <Image   local:orbitpanel.Orbit="0"   HorizontalAlignment="Left" Height="166" PointerEntered="image_PointerEntered_1" PointerExited="image_PointerExited_1"  Margin="449,349,0,0" VerticalAlignment="Top" Width="261" Source="http://img.trip.elong.com/guide/attachments/bc/d1/be/bcd1bef731bbde7796bb55edbed0fc1f.jpg" RenderTransformOrigin="0.5,0.5">          
        </Image>
        <Image   local:orbitpanel.Orbit="0"   HorizontalAlignment="Left" Height="166" PointerEntered="image_PointerEntered_1" PointerExited="image_PointerExited_1"  Margin="449,349,0,0" VerticalAlignment="Top" Width="261" Source="http://img.trip.elong.com/guide/attachments/bc/d1/be/bcd1bef731bbde7796bb55edbed0fc1f.jpg" RenderTransformOrigin="0.5,0.5">          </Image>       
        <Image  local:orbitpanel.Orbit="0"   HorizontalAlignment="Left" Height="166" PointerEntered="image_PointerEntered_1" PointerExited="image_PointerExited_1"  Margin="449,349,0,0" VerticalAlignment="Top" Width="261" Source="http://img.trip.elong.com/guide/attachments/bc/d1/be/bcd1bef731bbde7796bb55edbed0fc1f.jpg" RenderTransformOrigin="0.5,0.5">           
        </Image>
        <Image  local:orbitpanel.Orbit="0"   HorizontalAlignment="Left" Height="166" PointerEntered="image_PointerEntered_1" PointerExited="image_PointerExited_1"  Margin="449,349,0,0" VerticalAlignment="Top" Width="261" Source="http://img.trip.elong.com/guide/attachments/bc/d1/be/bcd1bef731bbde7796bb55edbed0fc1f.jpg" RenderTransformOrigin="0.5,0.5">           
        </Image>
        <Image  local:orbitpanel.Orbit="0"   HorizontalAlignment="Left" Height="166" PointerEntered="image_PointerEntered_1" PointerExited="image_PointerExited_1"  Margin="449,349,0,0" VerticalAlignment="Top" Width="261" Source="http://img.trip.elong.com/guide/attachments/bc/d1/be/bcd1bef731bbde7796bb55edbed0fc1f.jpg" RenderTransformOrigin="0.5,0.5">           
        </Image>

    </local:orbitpanel>