add Fragment property for #77

whistyun · Nov 17, 2023 · 9a62b1c · 9a62b1c
1 parent c101963
commit 9a62b1c
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Showing 4 changed files with 154 additions and 25 deletions.
diff --git a/MdXaml/LinkActions/DiaplayCommand.cs b/MdXaml/LinkActions/DiaplayCommand.cs
@@ -43,6 +43,11 @@ public void Execute(object? parameter)
             var path = parameter?.ToString();
             if (path is null) throw new ArgumentNullException(nameof(parameter));
 
+            if (path.StartsWith("file:///"))
+            {
+                path = path.Replace('\\', '/');
+            }
+
             var isAbs = Uri.IsWellFormedUriString(path, UriKind.Absolute);
 
             if (OpenBrowserWithAbsolutePath & isAbs)

diff --git a/MdXaml/LinkActions/FlowDocumentJumpAnchorIfNecessary.cs b/MdXaml/LinkActions/FlowDocumentJumpAnchorIfNecessary.cs
@@ -33,22 +33,7 @@ public void Execute(object? parameter)
         {
             if (parameter is string linkText && linkText.StartsWith("#"))
             {
-                var identifier = linkText.Substring(1);
-                if (_viewer.Document is null)
-                {
-                    Debug.Print($"MarkdownScrollViewer is uninitialized.");
-                    return;
-                }
-
-                var anchor = DocumentAnchor.FindAnchor(_viewer.Document, identifier);
-
-                if (anchor is null)
-                {
-                    Debug.Print($"Not found linkanchor: {identifier}");
-                    return;
-                }
-
-                anchor.BringIntoView();
+                _viewer.ScrollTo(linkText, true);
             }
             else _command.Execute(parameter);
         }

diff --git a/MdXaml/MarkdownScrollViewer.cs b/MdXaml/MarkdownScrollViewer.cs
@@ -16,9 +16,14 @@
 
 using MdXaml.LinkActions;
 using MdStyle = MdXaml.MarkdownStyle;
+using System.ComponentModel;
+using System.Windows.Media.Media3D;
+using System.Windows.Threading;
+using System.Threading.Tasks;
 
 namespace MdXaml
 {
+    // Markdownを表示するためのControl
     [ContentProperty(nameof(HereMarkdown))]
     public class MarkdownScrollViewer : FlowDocumentScrollViewer, IUriContext
     {
@@ -29,6 +34,14 @@ public class MarkdownScrollViewer : FlowDocumentScrollViewer, IUriContext
                  typeof(MarkdownScrollViewer),
                  new PropertyMetadata(null, UpdateSource));
 
+        public static readonly DependencyProperty FragmentProperty =
+             DependencyProperty.Register(
+                 nameof(Fragment),
+                 typeof(string),
+                 typeof(MarkdownScrollViewer),
+                 new PropertyMetadata(null, UpdateFragment));
+
+
         public static readonly DependencyProperty MarkdownProperty =
             DependencyProperty.Register(
                 nameof(Markdown),
@@ -63,7 +76,27 @@ private static void UpdateSource(DependencyObject d, DependencyPropertyChangedEv
         {
             if (d is MarkdownScrollViewer owner && e.NewValue is Uri source)
             {
-                owner.Open(source, false);
+                if (owner._source != source)
+                {
+                    owner._source = source;
+                    owner.Open(source, false);
+                }
+                else if (owner.Fragment != source.Fragment)
+                {
+                    owner.SetCurrentValue(FragmentProperty, source.Fragment);
+                }
+            }
+        }
+
+        private static void UpdateFragment(DependencyObject d, DependencyPropertyChangedEventArgs e)
+        {
+            if (d is MarkdownScrollViewer owner && e.NewValue is string fragment)
+            {
+                if (owner._fragment != fragment)
+                {
+                    owner._fragment = fragment;
+                    owner.ScrollTo(fragment, false);
+                }
             }
         }
 
@@ -122,14 +155,17 @@ private static void UpdateAssetPathRoot(DependencyObject d, DependencyPropertyCh
             if (d is MarkdownScrollViewer owner)
             {
                 var newPath = (string)e.NewValue;
-                var shouldUpdateMd = newPath != owner.Engine.AssetPathRoot;
-
-                owner.Engine.AssetPathRoot = (string)e.NewValue;
-
-                if (shouldUpdateMd) UpdateMarkdown(d, e);
+                if (newPath != owner.Engine.AssetPathRoot)
+                {
+                    owner.Engine.AssetPathRoot = newPath;
+                    UpdateMarkdown(d, e);
+                }
             }
         }
 
+        private string _fragment;
+        private Uri _source;
+
         private Markdown _engine;
         public Markdown Engine
         {
@@ -275,6 +311,12 @@ public Uri? Source
             set { SetValue(SourceProperty, value); }
         }
 
+        public string Fragment
+        {
+            get { return (string)GetValue(FragmentProperty); }
+            set { SetValue(FragmentProperty, value); }
+        }
+
         private ClickAction _clickAction;
         public ClickAction ClickAction
         {
@@ -331,6 +373,17 @@ public MarkdownScrollViewer()
             menu.Items.Add(ApplicationCommands.SelectAll);
 
             ContextMenu = menu;
+
+
+            DependencyPropertyDescriptor
+                .FromProperty(FlowDocumentScrollViewer.DocumentProperty, typeof(FlowDocumentScrollViewer))
+                .AddValueChanged(this, OnDocumentChanged);
+        }
+
+        private void OnDocumentChanged(object sender, EventArgs handler)
+        {
+            if (Document is not null)
+                ScrollTo(Fragment, false);
         }
 
         private void UpdateClickAction()
@@ -365,6 +418,65 @@ private void UpdateClickAction()
             Engine.HyperlinkCommand = new FlowDocumentJumpAnchorIfNecessary(this, command);
         }
 
+        internal void ScrollTo(string fragment, bool updateSourceProperty)
+        {
+            if (updateSourceProperty)
+            {
+                _fragment = fragment;
+                SetCurrentValue(FragmentProperty, fragment);
+            }
+
+
+            if (String.IsNullOrEmpty(fragment))
+                return;
+
+            if (Document is null)
+            {
+                Debug.Print($"MarkdownScrollViewer is uninitialized.");
+                return;
+            }
+
+            var identifier = fragment.StartsWith("#") ?
+                                    fragment.Substring(1) :
+                                    fragment;
+
+            var anchor = DocumentAnchor.FindAnchor(Document, identifier);
+            if (anchor is null)
+            {
+                Debug.Print($"Not found linkanchor: {identifier}");
+                return;
+            }
+
+            if (anchor.IsLoaded)
+            {
+                /*
+                 * dirty hack
+                 * 
+                 * I have no idea to detect a text element position in ScrollViewer.
+                 * BringIntoView has no effect if text element is placed in Viewport,
+                 * so scroll to the top once.
+                 */
+                var scroll = GetScrollViewer();
+                scroll?.ScrollToTop();
+                Dispatcher.Invoke(() => anchor.BringIntoView(), DispatcherPriority.Render);
+            }
+            else
+                anchor.Loaded += (s, e) =>
+                {
+                    /*
+                     * dirty hack
+                     * 
+                     * BringIntoView fails to scroll at correct position when Loaded only.
+                     */
+                    Dispatcher.Invoke(async () =>
+                    {
+                        await Task.Delay(100);
+                        Dispatcher.Invoke(anchor.BringIntoView, DispatcherPriority.Background);
+                    }, DispatcherPriority.Background);
+                };
+
+        }
+
         internal void Open(Uri source, bool updateSourceProperty)
         {
             bool TryOpen(Uri path)
@@ -401,13 +513,20 @@ bool TryOpen(Uri path)
 
                     var assetPathRoot = path.Scheme == "file" ? Path.GetDirectoryName(path.LocalPath) : path.AbsoluteUri;
 
+                    // suppress property changed
                     Engine.AssetPathRoot = assetPathRoot;
-
                     SetCurrentValue(AssetPathRootProperty, assetPathRoot);
-                    SetCurrentValue(MarkdownProperty, newMdTxt);
+
+                    _fragment = path.Fragment;
+                    SetCurrentValue(FragmentProperty, path.Fragment);
 
                     if (updateSourceProperty)
+                    {
+                        _source = path;
                         SetCurrentValue(SourceProperty, path);
+                    }
+
+                    SetCurrentValue(MarkdownProperty, newMdTxt);
 
                     return true;
                 }
@@ -443,6 +562,27 @@ bool TryOpen(Uri path)
                 Debug.WriteLine($"Failed to open markdown from relative path '{source}': not found");
             }
         }
+
+        private ScrollViewer GetScrollViewer()
+        {
+            ScrollViewer Find(Visual visual)
+            {
+                for (int i = 0; i < VisualTreeHelper.GetChildrenCount(visual); i++)
+                {
+                    var child = VisualTreeHelper.GetChild(visual, i);
+
+                    if (child is ScrollViewer scroll)
+                        return scroll;
+
+                    if (child is Visual vis)
+                        return Find(vis);
+                }
+
+                return null;
+            }
+
+            return Find(this);
+        }
     }
 
     public enum ClickAction

diff --git a/samples/MdXaml.Demo2/MainWindowViewModel.cs b/samples/MdXaml.Demo2/MainWindowViewModel.cs
@@ -24,7 +24,6 @@ public Uri MdSource
             get => _MdSource;
             set
             {
-                if (_MdSource == value) return;
                 _MdSource = value;
 
                 Histories.Add(value);