using System;
using System.Collections.Generic;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Interop;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using System.Windows.Threading;
using Brush = System.Windows.Media.Brush;
using Color = System.Windows.Media.Color;
using Point = System.Windows.Point;

namespace WpfSketch
{
    /// <summary>
    /// Window1.xaml 的交互逻辑
    /// </summary>
    public partial class Window1 : Window
    {
        public delegate void ImageSaveEventHandler(BitmapSource image);
        public ImageSaveEventHandler ImageSaveEvent;
        private ColorPicker DefaultColorPicker;
        public string ImageFile { get; set; }
        /// <summary>
        /// 目标图片
        /// </summary>
        public BitmapSource DestImage { get; set; } = null;
        private static Mutex mutex = new Mutex(true, "alldream-WpfSketch");
        public Window1()
        {
            _history = new Stack<StrokesHistoryNode>();
            _redoHistory = new Stack<StrokesHistoryNode>();

            InitializeComponent();
            //ImageFile = "C:\\temp\\out-m.png";
            DefaultColorPicker = new ColorPicker();
            //SetColor(DefaultColorPicker);
            _selectedColor = DefaultColorPicker;

            SetEnable(false, _mode);

            SetTopMost(true);

            SetBrushSize(_brushSizes[_brushIndex]);

            //ExtraToolPanel.Opacity = 0;
            btnFontIncrease.Visibility = Visibility.Hidden;
            btnFontDecrease.Visibility = Visibility.Hidden;

            MainInkCanvas.Strokes.StrokesChanged += StrokesChanged;

            //MainInkCanvas.AddHandler(InkCanvas.MouseLeftButtonDownEvent, new MouseButtonEventHandler(MainInkCanvas_MouseLeftButtonDown), true);
            //MainInkCanvas.MouseLeftButtonDown += MainInkCanvas_MouseLeftButtonDown;
            MainInkCanvas.PreviewMouseLeftButtonDown += MainInkCanvas_MouseLeftButtonDown;
            MainInkCanvas.MouseLeftButtonUp += MainInkCanvas_MouseLeftButtonUp;
            MainInkCanvas.MouseRightButtonUp += MainInkCanvas_MouseRightButtonUp;
            MainInkCanvas.MouseMove += MainInkCanvas_MouseMove;

            _drawerTextBox.IsHitTestVisible = true;
            _drawerTextBox.FontSize = 24.0;
            //_drawerTextBox.Background = Application.Current.Resources["TrueTransparent"] as Brush;
            _drawerTextBox.Background = System.Windows.Media.Brushes.Transparent;// 
            _drawerTextBox.AcceptsReturn = true;
            _drawerTextBox.TextWrapping = TextWrapping.Wrap;
            _drawerTextBox.LostFocus += _drawerTextBox_LostFocus;
        }
        public Window1(BitmapSource destImage)
            : this()
        {
            this.DestImage = destImage;
        }
        #region /---------Setter---------/

        private ColorPicker _selectedColor;
        private bool _inkVisibility = true;
        private bool _displayExtraToolPanel = false;
        private bool _enable = false;
        private readonly int[] _brushSizes = { 4, 6, 8, 10, 14 };
        private int _brushIndex = 0;
        private bool _displayOrientation;
        private DrawMode _mode = DrawMode.Pen;

        private void SetEnable(bool enable, DrawMode mode)
        {
            _enable = enable;
            _mode = mode;

            InkCanvasEditingMode editingMode = InkCanvasEditingMode.Ink;
            bool bUseCustomCursor = true;

            switch (_mode)
            {
                case DrawMode.Select:
                    bUseCustomCursor = false;
                    editingMode = InkCanvasEditingMode.Select;
                    break;
                case DrawMode.Pen:
                    editingMode = InkCanvasEditingMode.Ink;
                    break;
                case DrawMode.Text:
                    editingMode = InkCanvasEditingMode.None;
                    break;
                case DrawMode.Line:
                    editingMode = InkCanvasEditingMode.None;
                    break;
                case DrawMode.Arrow:
                    editingMode = InkCanvasEditingMode.None;
                    break;
                case DrawMode.Rectangle:
                    editingMode = InkCanvasEditingMode.None;
                    break;
                case DrawMode.Circle:
                    editingMode = InkCanvasEditingMode.None;
                    break;
                case DrawMode.Ray:
                    editingMode = InkCanvasEditingMode.None;
                    break;
                case DrawMode.Erase:
                    bUseCustomCursor = false;
                    editingMode = InkCanvasEditingMode.EraseByStroke;
                    break;
                case DrawMode.None:
                    _mode = DrawMode.None;
                    break;
                default:
                    _mode = DrawMode.Select;
                    break;
            }

            if (_mode == DrawMode.Ray)
            {
                MainInkCanvas.Cursor = new System.Windows.Input.Cursor(new MemoryStream(WpfSketch.Properties.Resources.激光));
            }
            else
            {
                MainInkCanvas.Cursor = System.Windows.Input.Cursors.Cross;
            }

            if (_mode == DrawMode.Text)
            {
                btnFontIncrease.Visibility = Visibility.Visible;
                btnFontDecrease.Visibility = Visibility.Visible;
            }
            else
            {
                btnFontIncrease.Visibility = Visibility.Hidden;
                btnFontDecrease.Visibility = Visibility.Hidden;
            }

            MainInkCanvas.UseCustomCursor = bUseCustomCursor;
            MainInkCanvas.EditingMode = editingMode;
            if (!_enable || _mode == DrawMode.None)
            {
                MainInkCanvas.EditingMode = InkCanvasEditingMode.None;
            }
            btnNone.IsChecked = !enable;
            //if(_mode == DrawMode.None)
            //{
            //    btnNone.IsChecked = true;
            //}
            // Background = Application.Current.Resources[enable ? "FakeTransparent" : "TrueTransparent"] as Brush;
        }
        //private void SetColor(ColorPicker b)
        //{
        //    if (ReferenceEquals(_selectedColor, b)) return;
        //    var solidColorBrush = b.Foreground as SolidColorBrush;
        //    if (solidColorBrush == null)
        //        return;

        //    MainInkCanvas.DefaultDrawingAttributes.Color = solidColorBrush.Color;

        //    b.IsActived = true;
        //    if (_selectedColor != null)
        //        _selectedColor.IsActived = false;
        //    _selectedColor = b;

        //    _drawerTextBox.Foreground = solidColorBrush;
        //}
        private void SetForeColor(Color color)
        {
            if(_selectedColor == null)
            {
                return;
            }
            var solidColorBrush = _selectedColor.Foreground as SolidColorBrush;

            solidColorBrush.Color = color;
            MainInkCanvas.DefaultDrawingAttributes.FitToCurve = true;
            MainInkCanvas.DefaultDrawingAttributes.IgnorePressure = false;
            MainInkCanvas.DefaultDrawingAttributes.IsHighlighter = false;
            MainInkCanvas.DefaultDrawingAttributes.StylusTip = StylusTip.Ellipse;

            MainInkCanvas.DefaultDrawingAttributes.Color = solidColorBrush.Color;

            _drawerTextBox.Foreground = solidColorBrush;
        }
        private void SetBrushSize(double s)
        {
            MainInkCanvas.DefaultDrawingAttributes.Height = s;
            MainInkCanvas.DefaultDrawingAttributes.Width = s;
        }
        private void SetOrientation(bool v)
        {
            //PaletteRotate.BeginAnimation(RotateTransform.AngleProperty, new DoubleAnimation(v ? -90 : 0, Duration4));
            //Palette.BeginAnimation(MinWidthProperty, new DoubleAnimation(v ? 90 : 0, Duration7));
            _displayOrientation = v;
        }
        private void SetTopMost(bool v)
        {
            //PinButton.IsActived = v;
            Topmost = v;
        }
        #endregion
        #region Shape Drawer
        private Point _drawerIntPos;
        private bool _drawerIsMove = false;
        private Stroke _drawerLastStroke;
        private System.Windows.Controls.TextBox _drawerTextBox = new System.Windows.Controls.TextBox();

        private void _drawerTextBox_LostFocus(object sender, RoutedEventArgs e)
        {
            String text = _drawerTextBox.Text;

            if (text.Length > 0)
            {
                var textBlock = new TextBlock();
                //textBlock.TextWrapping = TextWrapping.NoWrap;
                textBlock.Text = text;

                MainInkCanvas.Children.Add(textBlock);

                textBlock.Visibility = Visibility.Visible;
                textBlock.Foreground = _drawerTextBox.Foreground;
                textBlock.FontSize = _drawerTextBox.FontSize;
                textBlock.TextWrapping = _drawerTextBox.TextWrapping;

                InkCanvas.SetLeft(textBlock, InkCanvas.GetLeft(_drawerTextBox));
                InkCanvas.SetTop(textBlock, InkCanvas.GetTop(_drawerTextBox));

                textBlock.Width = _drawerTextBox.Width;
                textBlock.Height = _drawerTextBox.Height;
            }

            MainInkCanvas.Children.Remove(_drawerTextBox);

            //throw new NotImplementedException();
        }
        private void MainInkCanvas_MouseRightButtonUp(object sender, MouseButtonEventArgs e)
        {
            SetEnable(false, _mode);
        }
        private void MainInkCanvas_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            if (_enable == false || _mode == DrawMode.Select || _mode == DrawMode.Pen || _mode == DrawMode.None || e.LeftButton != MouseButtonState.Pressed)
            {
                return;
            }
            if (MainInkCanvas.Children.Contains(_drawerTextBox))
            {
                return;
            }
            
            _ignoreStrokesChange = true;
            _drawerIsMove = true;
            _drawerIntPos = e.GetPosition(MainInkCanvas);
            _drawerLastStroke = null;
            
            if (_mode == DrawMode.Text)
            {
                _drawerTextBox.Text = "";

                if (MainInkCanvas.Children.Contains(_drawerTextBox) == false)
                    MainInkCanvas.Children.Add(_drawerTextBox);

                _drawerTextBox.Visibility = Visibility.Visible;
                InkCanvas.SetLeft(_drawerTextBox, _drawerIntPos.X);
                InkCanvas.SetTop(_drawerTextBox, _drawerIntPos.Y);
                _drawerTextBox.Width = 0;
                _drawerTextBox.Height = 0;
            }
        }

        private void MainInkCanvas_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
        {
            if (_drawerIsMove == true)
            {
                Point endP = e.GetPosition(MainInkCanvas);

                if (_drawerLastStroke != null && _mode != DrawMode.Ray && _mode != DrawMode.Text)
                {
                    StrokeCollection collection = new StrokeCollection();
                    collection.Add(_drawerLastStroke);
                    Push(_history, new StrokesHistoryNode(collection, StrokesHistoryNodeType.Added));
                }

                if (_drawerLastStroke != null && (_mode == DrawMode.Ray || _mode == DrawMode.Text))
                {
                    //us animation?
                    /*
                    var ani = new DoubleAnimation(1, 1, Duration4);
                    ani.Completed += (obj,arg)=> { MainInkCanvas.Strokes.Remove(_drawerLastStroke); };
                    MainInkCanvas.BeginAnimation(OpacityProperty, ani);
                    */
                    MainInkCanvas.Strokes.Remove(_drawerLastStroke);
                }

                if (_mode == DrawMode.Text)
                {
                    // resize drawer text box
                    _drawerTextBox.Width = Math.Abs(endP.X - _drawerIntPos.X);
                    _drawerTextBox.Height = Math.Abs(endP.Y - _drawerIntPos.Y);

                    if (_drawerTextBox.Width <= 100 || _drawerTextBox.Height <= 40)
                    {
                        _drawerTextBox.Width = 100;
                        _drawerTextBox.Height = 40;
                    }

                    InkCanvas.SetLeft(_drawerTextBox, Math.Min(_drawerIntPos.X, endP.X));
                    InkCanvas.SetTop(_drawerTextBox, Math.Min(_drawerIntPos.Y, endP.Y));

                    _drawerTextBox.Focus();
                }

                _drawerIsMove = false;
                _ignoreStrokesChange = false;
            }
            else
            {
                if (_mode != DrawMode.Select)
                {
                    if (_mode == DrawMode.None)
                    {
                        SetEnable(false, _mode);
                    }
                    else
                    {
                        DrawMode mode = _mode;
                        SetEnable(true, DrawMode.None);
                        SetEnable(true, mode);
                    }
                }
                //else
                //{
                //    //SetEnable(true, _mode);
                //    //_enable = true;
                //}
            }
        }

        private void MainInkCanvas_MouseMove(object sender, System.Windows.Input.MouseEventArgs e)
        {
            if (_drawerIsMove == false)
                return;

            DrawingAttributes drawingAttributes = MainInkCanvas.DefaultDrawingAttributes.Clone();
            Stroke stroke = null;

            drawingAttributes.StylusTip = StylusTip.Ellipse;
            drawingAttributes.IgnorePressure = true;

            Point endP = e.GetPosition(MainInkCanvas);

            if (_mode == DrawMode.Text)
            {
                List<Point> pointList = new List<Point>
                {
                    new Point(_drawerIntPos.X, _drawerIntPos.Y),
                    new Point(_drawerIntPos.X, endP.Y),
                    new Point(endP.X, endP.Y),
                    new Point(endP.X, _drawerIntPos.Y),
                    new Point(_drawerIntPos.X, _drawerIntPos.Y),
                };

                drawingAttributes.Width = 2;
                drawingAttributes.Height = 2;
                drawingAttributes.FitToCurve = false;//must be false,other wise rectangle can not be drawed correct

                StylusPointCollection point = new StylusPointCollection(pointList);
                stroke = new Stroke(point)
                {
                    DrawingAttributes = drawingAttributes,
                };
            }
            else if (_mode == DrawMode.Ray)
            {
                //high lighter is ray line
                drawingAttributes.IsHighlighter = true;

                List<Point> pointList = new List<Point>
                {
                    new Point(_drawerIntPos.X, _drawerIntPos.Y),
                    new Point(endP.X, endP.Y),
                };

                StylusPointCollection point = new StylusPointCollection(pointList);
                stroke = new Stroke(point)
                {
                    DrawingAttributes = drawingAttributes,
                };
            }
            else if (_mode == DrawMode.Line)
            {
                List<Point> pointList = new List<Point>
                {
                    new Point(_drawerIntPos.X, _drawerIntPos.Y),
                    new Point(endP.X, endP.Y),
                };

                StylusPointCollection point = new StylusPointCollection(pointList);
                stroke = new Stroke(point)
                {
                    DrawingAttributes = drawingAttributes,
                };
            }
            else if (_mode == DrawMode.Arrow)
            {
                double w = 15, h = 15;
                double theta = Math.Atan2(_drawerIntPos.Y - endP.Y, _drawerIntPos.X - endP.X);
                double sint = Math.Sin(theta);
                double cost = Math.Cos(theta);

                List<Point> pointList = new List<Point>
                {
                    new Point(_drawerIntPos.X, _drawerIntPos.Y),
                    new Point(endP.X , endP.Y),
                    new Point(endP.X + (w*cost - h*sint), endP.Y + (w*sint + h*cost)),
                    new Point(endP.X,endP.Y),
                    new Point(endP.X + (w*cost + h*sint), endP.Y - (h*cost - w*sint)),
                };

                StylusPointCollection point = new StylusPointCollection(pointList);

                drawingAttributes.FitToCurve = false;//must be false,other wise rectangle can not be drawed correct

                stroke = new Stroke(point)
                {
                    DrawingAttributes = drawingAttributes,
                };
            }
            else if (_mode == DrawMode.Rectangle)
            {
                List<Point> pointList = new List<Point>
                {
                    new Point(_drawerIntPos.X, _drawerIntPos.Y),
                    new Point(_drawerIntPos.X, endP.Y),
                    new Point(endP.X, endP.Y),
                    new Point(endP.X, _drawerIntPos.Y),
                    new Point(_drawerIntPos.X, _drawerIntPos.Y),
                };

                drawingAttributes.FitToCurve = false;//must be false,other wise rectangle can not be drawed correct

                StylusPointCollection point = new StylusPointCollection(pointList);
                stroke = new Stroke(point)
                {
                    DrawingAttributes = drawingAttributes,
                };
            }
            else if (_mode == DrawMode.Circle)
            {
                List<Point> pointList = GenerateEclipseGeometry(_drawerIntPos, endP);
                StylusPointCollection point = new StylusPointCollection(pointList);
                stroke = new Stroke(point)
                {
                    DrawingAttributes = drawingAttributes
                };
            }

            if (_drawerLastStroke != null)
                MainInkCanvas.Strokes.Remove(_drawerLastStroke);

            if (stroke != null)
                MainInkCanvas.Strokes.Add(stroke);

            _drawerLastStroke = stroke;
        }

        #endregion
        #region /---------Generator---------/
        private static string GenerateFileName(string fileExt = ".fdw")
        {
            return DateTime.Now.ToString("yyyyMMdd-HHmmss") + fileExt;
        }

        private List<Point> GenerateEclipseGeometry(Point st, Point ed)
        {
            double a = 0.5 * (ed.X - st.X);
            double b = 0.5 * (ed.Y - st.Y);
            List<Point> pointList = new List<Point>();
            for (double r = 0; r <= 2 * Math.PI; r = r + 0.01)
            {
                pointList.Add(new Point(0.5 * (st.X + ed.X) + a * Math.Cos(r), 0.5 * (st.Y + ed.Y) + b * Math.Sin(r)));
            }
            return pointList;
        }
        #endregion
        #region /---------IO---------/
        private StrokeCollection _preLoadStrokes = null;
        private void QuickSave(string filename = "QuickSave_")
        {
            //Save(new FileStream("Save\\" + filename + GenerateFileName(), FileMode.OpenOrCreate));
            if(this.DestImage != null)
            {
                Save2Image();
            }
            else
            {
                Save(null);
            }
        }
        private void Save2Image()
        {
            try
            {
                //string strFile = "C:\\temp\\rend.png";
                double width = MainInkCanvas.ActualWidth;
                double height = MainInkCanvas.ActualHeight;
                RenderTargetBitmap bmpCopied = new RenderTargetBitmap((int)Math.Round(width)
                    , (int)Math.Round(height), 96, 96, PixelFormats.Default);
                DrawingVisual dv = new DrawingVisual();
                using (DrawingContext dc = dv.RenderOpen())
                {
                    VisualBrush vb = new VisualBrush(MainInkCanvas);
                    dc.DrawImage(this.img.Source, new Rect(new System.Windows.Point(), new System.Windows.Size(width, height)));
                    dc.DrawRectangle(vb, null, new Rect(new System.Windows.Point(), new System.Windows.Size(width, height)));
                }
                bmpCopied.Render(dv);
                this.DestImage = bmpCopied;
                _saved = true;
                ImageSaveEvent?.Invoke(this.DestImage);
            }
            catch (Exception ex)
            {
                System.Windows.MessageBox.Show(ex.Message);
            }
        }
        private void Save(Stream fs)
        {
            try
            {
                //string strFile = "C:\\temp\\rend.png";
                double width = MainInkCanvas.ActualWidth;
                double height = MainInkCanvas.ActualHeight;
                RenderTargetBitmap bmpCopied = new RenderTargetBitmap((int)Math.Round(width)
                    , (int)Math.Round(height), 96, 96, PixelFormats.Default);
                DrawingVisual dv = new DrawingVisual();
                using (DrawingContext dc = dv.RenderOpen())
                {
                    VisualBrush vb = new VisualBrush(MainInkCanvas);
                    dc.DrawImage(this.img.Source, new Rect(new System.Windows.Point(), new System.Windows.Size(width, height)));
                    dc.DrawRectangle(vb, null, new Rect(new System.Windows.Point(), new System.Windows.Size(width, height)));
                }
                bmpCopied.Render(dv);
                using (FileStream file = new FileStream(ImageFile, FileMode.Create, FileAccess.Write))
                {
                    PngBitmapEncoder encoder = new PngBitmapEncoder();
                    encoder.Frames.Add(BitmapFrame.Create(bmpCopied));
                    encoder.Save(file);
                    _saved = true;
                }
            }
            catch(Exception ex)
            {
                System.Windows.MessageBox.Show(ex.Message);
            }
            //try
            //{
            //    if (fs == Stream.Null) return;
            //    MainInkCanvas.Strokes.Save(fs);
            //    _saved = true;
            //    Display("画板保存成功");
            //    fs.Close();
            //}
            //catch (Exception ex)
            //{
            //    MessageBox.Show(ex.ToString());
            //    Display("画板保存失败");
            //}
        }
        private StrokeCollection Load(Stream fs)
        {
            try
            {
                return new StrokeCollection(fs);
            }
            catch (Exception ex)
            {
                System.Windows.MessageBox.Show(ex.ToString());
                Display("画板加载失败");
            }
            return new StrokeCollection();
        }
        private void AnimatedReload(StrokeCollection sc)
        {
            _preLoadStrokes = sc;
            //var ani = new DoubleAnimation(0, Duration3);
            //ani.Completed += LoadAniCompleted;
            //MainInkCanvas.BeginAnimation(OpacityProperty, ani);
        }
        private void LoadAniCompleted(object sender, EventArgs e)
        {
            if (_preLoadStrokes == null) return;
            MainInkCanvas.Strokes = _preLoadStrokes;
            //Display("画板加载完成");
            _saved = true;
            ClearHistory();
            //MainInkCanvas.BeginAnimation(OpacityProperty, new DoubleAnimation(1, Duration3));
        }

        private static string[] GetSavePathList()
        {
            return Directory.GetFiles("Save", "*.fdw");
        }
        private static string GetFileNameFromPath(string path)
        {
            return System.IO.Path.GetFileName(path);
        }
        #endregion
        #region /---------Helper---------/
        private string _staticInfo = "";
        private bool _displayingInfo;

        private async void Display(string info)
        {
            //InfoBox.Text = info;
            _displayingInfo = true;
            //await InfoDisplayTimeUp(new Progress<string>(box => InfoBox.Text = box));
        }
        private Task InfoDisplayTimeUp(IProgress<string> box)
        {
            return Task.Run(() =>
            {
                Task.Delay(2000).Wait();
                box.Report(_staticInfo);
                _displayingInfo = false;
            });
        }
        private void SetStaticInfo(string info)
        {
            _staticInfo = info;
            //if (!_displayingInfo)
            //    InfoBox.Text = _staticInfo;
        }

        private static Stream SaveDialog(string initFileName, string fileExt = ".fdw", string filter = "Free Draw Save (*.fdw)|*fdw")
        {
            var dialog = new Microsoft.Win32.SaveFileDialog()
            {
                DefaultExt = fileExt,
                Filter = filter,
                FileName = initFileName,
                InitialDirectory = Directory.GetCurrentDirectory() + "Save"
            };
            return dialog.ShowDialog() == true ? dialog.OpenFile() : Stream.Null;
        }
        private static Stream OpenDialog(string fileExt = ".fdw", string filter = "Free Draw Save (*.fdw)|*fdw")
        {
            var dialog = new Microsoft.Win32.OpenFileDialog()
            {
                DefaultExt = fileExt,
                Filter = filter,
            };
            return dialog.ShowDialog() == true ? dialog.OpenFile() : Stream.Null;
        }
        #endregion
        #region /---------Judge--------/

        private bool _saved = false;

        private bool IsUnsaved()
        {
            return MainInkCanvas.Strokes.Count != 0 && !_saved;
        }

        private bool PromptToSave()
        {
            if (!IsUnsaved())
                return true;
            var r = System.Windows.MessageBox.Show("You have unsaved work, do you want to save it now?", "Unsaved data",
                MessageBoxButton.YesNoCancel);
            if (r == MessageBoxResult.Yes || r == MessageBoxResult.OK)
            {
                QuickSave();
                return true;
            }
            if (r == MessageBoxResult.No || r == MessageBoxResult.None)
                return true;
            return false;
        }

        #endregion
        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            FixupToolBarOverflowArrow(tbDraw);
            if(this.DestImage != null)
            {
                MainInkCanvas.Width = this.DestImage.Width;
                MainInkCanvas.Height = this.DestImage.Height;

                img.Source = this.DestImage;
            }
            else if (!string.IsNullOrEmpty(ImageFile))
            {
                MemoryStream ms = null;
                using (var stream = File.Open(ImageFile, FileMode.Open))
                {
                    using (var reader = new BinaryReader(stream))
                    {
                        byte[] datas = reader.ReadBytes((int)stream.Length);
                        ms = new MemoryStream(datas);
                    }
                }

                BitmapImage imgSource = new BitmapImage();
                imgSource.BeginInit();
                imgSource.StreamSource = ms;
                imgSource.EndInit();

                MainInkCanvas.Width = imgSource.Width;
                MainInkCanvas.Height = imgSource.Height;

                img.Source = imgSource;
            }
            else
            {
                MainInkCanvas.Width = 500;
                MainInkCanvas.Height = 400;
            }

            // 默认红色画笔
            this.btnColorRed.IsChecked = true;
            this.btnColorRed.RaiseEvent(new RoutedEventArgs(System.Windows.Controls.RadioButton.ClickEvent));
            this.rbtnPenWidthMin.IsChecked = true;

            // 默认绘图圆
            this.btnCircle.IsChecked = true;
            this.btnCircle.RaiseEvent(new RoutedEventArgs(System.Windows.Controls.RadioButton.ClickEvent));
        }

        private static void FixupToolBarOverflowArrow(ToolBar toolBar)
        {
            Action fixup = () =>
            {
                var overflowButton = toolBar.Template.FindName("OverflowButton", toolBar) as System.Windows.Controls.Primitives.ButtonBase;
                if (overflowButton != null)
                {
                    overflowButton.SetBinding(
                        VisibilityProperty,
                        new System.Windows.Data.Binding("IsEnabled")
                        {
                            RelativeSource = RelativeSource.Self,
                            Converter = new BooleanToVisibilityConverter()
                        });
                }
            };

            if (toolBar.IsLoaded)
            {
                fixup();
            }
            else
            {
                RoutedEventHandler handler = null;
                handler = (sender, e) =>
                {
                    fixup();
                    toolBar.Loaded -= handler;
                };

                toolBar.Loaded += handler;
            }
        }
        /// <summary>
        /// 选择颜色.
        /// </summary>
        /// <param name="sender">The sender.</param>
        /// <param name="e">The e.</param>
        private void ColorButton_Click(object sender, RoutedEventArgs e)
        {
            //要获得所选方块的颜色，需要将SolidColorBrush取Color
            //_selectedColor.Foreground = (SolidColorBrush)((Rectangle)(sender as RadioButton).Content).Fill;
            Color color = ((SolidColorBrush)((System.Windows.Shapes.Rectangle)(sender as System.Windows.Controls.RadioButton).Content).Fill).Color;
            this.SetForeColor(color);
        }
        #region /---------Ink---------/
        private readonly Stack<StrokesHistoryNode> _history;
        private readonly Stack<StrokesHistoryNode> _redoHistory;
        private bool _ignoreStrokesChange;

        private void Undo()
        {
            if (!CanUndo()) return;
            var last = Pop(_history);
            _ignoreStrokesChange = true;
            if (last.Type == StrokesHistoryNodeType.Added)
                MainInkCanvas.Strokes.Remove(last.Strokes);
            else
                MainInkCanvas.Strokes.Add(last.Strokes);
            _ignoreStrokesChange = false;
            Push(_redoHistory, last);
        }
        private void Redo()
        {
            if (!CanRedo()) return;
            var last = Pop(_redoHistory);
            _ignoreStrokesChange = true;
            if (last.Type == StrokesHistoryNodeType.Removed)
                MainInkCanvas.Strokes.Remove(last.Strokes);
            else
                MainInkCanvas.Strokes.Add(last.Strokes);
            _ignoreStrokesChange = false;
            Push(_history, last);
        }

        private static void Push(Stack<StrokesHistoryNode> collection, StrokesHistoryNode node)
        {
            collection.Push(node);
        }
        private static StrokesHistoryNode Pop(Stack<StrokesHistoryNode> collection)
        {
            return collection.Count == 0 ? null : collection.Pop();
        }
        private bool CanUndo()
        {
            return _history.Count != 0;
        }
        private bool CanRedo()
        {
            return _redoHistory.Count != 0;
        }
        private void StrokesChanged(object sender, StrokeCollectionChangedEventArgs e)
        {
            if (_ignoreStrokesChange) return;
            _saved = false;
            if (e.Added.Count != 0)
                Push(_history, new StrokesHistoryNode(e.Added, StrokesHistoryNodeType.Added));
            if (e.Removed.Count != 0)
                Push(_history, new StrokesHistoryNode(e.Removed, StrokesHistoryNodeType.Removed));
            ClearHistory(_redoHistory);
        }

        private void ClearHistory()
        {
            ClearHistory(_history);
            ClearHistory(_redoHistory);
        }
        private static void ClearHistory(Stack<StrokesHistoryNode> collection)
        {
            collection?.Clear();
        }
        private void Clear()
        {
            MainInkCanvas.Children.Clear();
            MainInkCanvas.Strokes.Clear();
            ClearHistory();
        }

        private void AnimatedClear()
        {
            //no need any more
            //var ani = new DoubleAnimation(0, Duration3);
            //ani.Completed += ClearAniComplete; ;
            //MainInkCanvas.BeginAnimation(OpacityProperty, ani);
        }
        private void ClearAniComplete(object sender, EventArgs e)
        {
            Clear();
            //Display("画板清除完成");
            //MainInkCanvas.BeginAnimation(OpacityProperty, new DoubleAnimation(1, Duration3));
        }
        #endregion        

        /// <summary>
        /// 绘制圆.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="RoutedEventArgs"/> instance containing the event data.</param>
        private void BtnCircle_Click(object sender, RoutedEventArgs e)
        {
            SetEnable(true, DrawMode.Circle);
        }
        /// <summary>
        /// 任意画笔.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="RoutedEventArgs"/> instance containing the event data.</param>
        private void BtnPen_Click(object sender, RoutedEventArgs e)
        {
            SetEnable(true, DrawMode.Pen);
        }
        /// <summary>
        /// 绘制直线
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void BtnLine_Click(object sender, RoutedEventArgs e)
        {
            SetEnable(true, DrawMode.Line);
        }

        private void BtnRectangle_Click(object sender, RoutedEventArgs e)
        {
            SetEnable(true, DrawMode.Rectangle);
        }

        private void BtnText_Click(object sender, RoutedEventArgs e)
        {
            SetEnable(true, DrawMode.Text);
        }

        private void BtnSelect_Click(object sender, RoutedEventArgs e)
        {
            SetEnable(true, DrawMode.Select);
        }
        private void BtnArrow_Click(object sender, RoutedEventArgs e)
        {
            SetEnable(true, DrawMode.Arrow);
        }
        private void BtnNone_Click(object sender, RoutedEventArgs e)
        {
            SetEnable(false, DrawMode.None);
        }

        private void BtnFontIncrease_Click(object sender, RoutedEventArgs e)
        {
            _drawerTextBox.FontSize = _drawerTextBox.FontSize + 2;
            _drawerTextBox.FontSize = Math.Min(60, _drawerTextBox.FontSize);
        }

        private void BtnFontDecrease_Click(object sender, RoutedEventArgs e)
        {
            _drawerTextBox.FontSize = _drawerTextBox.FontSize - 2;

            _drawerTextBox.FontSize = Math.Max(14, _drawerTextBox.FontSize);
        }
        /// <summary>
        /// 撤销.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="RoutedEventArgs"/> instance containing the event data.</param>
        private void BtnUndo_Click(object sender, RoutedEventArgs e)
        {
            Undo();
        }
        /// <summary>
        /// 重做.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="RoutedEventArgs"/> instance containing the event data.</param>
        private void BtnRedo_Click(object sender, RoutedEventArgs e)
        {
            Redo();
        }

        private void PenWidth_Checked(object sender, RoutedEventArgs e)
        {
            double dWidth = ((Ellipse)(sender as System.Windows.Controls.RadioButton).Content).Width;
            SetBrushSize(dWidth);
        }
        /// <summary>
        /// 保存.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="RoutedEventArgs"/> instance containing the event data.</param>
        private void BtnSave_Click(object sender, RoutedEventArgs e)
        {
            if (MainInkCanvas.Strokes.Count == 0)
            {
                Display("没有笔迹要保存");
                return;
            }
            QuickSave();

            this.Close();
        }
        /// <summary>
        /// 退出.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="RoutedEventArgs"/> instance containing the event data.</param>
        private void BtnExit_Click(object sender, RoutedEventArgs e)
        {
            this.Close();
        }

        private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            if (IsUnsaved())
            {
                if (System.Windows.MessageBox.Show(this, "尚未保存，是否退出？", "退出"
                    , MessageBoxButton.YesNo, MessageBoxImage.Question
                    , MessageBoxResult.No) == MessageBoxResult.Yes)
                {
                    //Application.Current.Shutdown();
                    //MessageBox.Show("退出");
                    return;
                }
                else
                {
                    e.Cancel = true;
                }
            }
        }
    }
}