ImageStackView.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace EroTool.View.UserCtl
{
    /// <summary>
    /// ImageStackView.xaml の相互作用ロジック
    /// </summary>
    public partial class ImageStackView : UserControl
    {
        public ImageStackView()
        {
            InitializeComponent();
            this.DataContextChanged += new DependencyPropertyChangedEventHandler(ImageStackView_DataContextChanged);
        }

        private object intnLock = new object();

        /// <summary>
        /// アップデート チケット
        /// </summary>
        private long Ticket = 0;

        void ImageStackView_DataContextChanged(object sender, DependencyPropertyChangedEventArgs e)
        {
            UpdateUI();
        }

        public int MaxStackingCount
        {
            get { return (int)GetValue(MaxStackingCountProperty); }
            set { SetValue(MaxStackingCountProperty, value); }
        }

        // Using a DependencyProperty as the backing store for MaxStackingCount.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty MaxStackingCountProperty =
            DependencyProperty.Register("MaxStackingCount", typeof(int), typeof(ImageStackView), new FrameworkPropertyMetadata(0, MaxStackingCountChanged));

        private static void MaxStackingCountChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
        {
            RegenerateUI(o as ImageStackView);
        }

        public void UpdateUI()
        {
            RegenerateUI(this);
        }

        static void RegenerateUI(ImageStackView stk)
        {
            if (stk == null) return;
            var ticket = System.Threading.Interlocked.Increment(ref stk.Ticket);
            var sources = (stk.DataContext as IEnumerable<BitmapImage>);
            stk.Stacker.Children.Clear();
            if (sources == null) return;
            var maxstk = stk.MaxStackingCount;
            stk.LoadingAnimation.Visibility = Visibility.Visible;
            var act = new Action(() =>
            {
                if (stk.Ticket != ticket) return;
                var src = (from i in sources.Take(maxstk) select i).Reverse().ToList();
                stk.Dispatcher.BeginInvoke(new Action(() =>
                {
                    var lo = LayoutLogic(stk, src);
                    lock (stk.intnLock)
                    {
                        if (stk.Ticket != ticket) return;
                        UpdateUI(stk, lo);
                    }
                }), null);
            });
            act.BeginInvoke((iar) => act.EndInvoke(iar), null);
        }

        static IEnumerable<UIElement> LayoutLogic(ImageStackView stk, List<BitmapImage> sources)
        {
            if (sources == null) yield break;
            
            if (sources.Count == 0)
                yield break;
            
            // 0 - 90°にバラける
            int ddeg = 90 / sources.Count;
            int cdeg = ddeg * (sources.Count - 1);
            foreach (var s in sources)
            {
                var img = new Image() { Source = s, Stretch = Stretch.Uniform };
                img.Width = 100;
                img.Height = 100;
                var border = new Border() { BorderBrush = Brushes.Gainsboro, BorderThickness = new Thickness(1), Background = new SolidColorBrush(Color.FromArgb(120, 255, 255, 255)) };
                border.LayoutTransform = new RotateTransform(cdeg);
                border.Child = img;
                yield return border;
                cdeg -= ddeg;
            }
        }

        static void UpdateUI(ImageStackView stk, IEnumerable<UIElement> lo)
        {
            foreach (var l in lo)
            {
                l.SetValue(Grid.HorizontalAlignmentProperty, HorizontalAlignment.Center);
                l.SetValue(Grid.VerticalAlignmentProperty, VerticalAlignment.Center);
                stk.Stacker.Children.Add(l);
            }
            stk.LoadingAnimation.Visibility = Visibility.Collapsed;
        }
    }
}