Add support for adding rich annotations to the workflow

Bonsai.Core/Bonsai.Core.csproj

@@ -6,7 +6,7 @@
     <PackageTags>Bonsai Rx Reactive Extensions</PackageTags>
     <TargetFrameworks>net462;netstandard2.0;net6.0</TargetFrameworks>
     <RootNamespace>Bonsai</RootNamespace>
-    <VersionPrefix>2.7.3</VersionPrefix>
+    <VersionPrefix>2.8.0</VersionPrefix>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'net462'">
     <PackageReference Include="Rx-Linq" Version="2.2.5" />

Bonsai.Core/Expressions/AnnotationBuilder.cs

@@ -0,0 +1,66 @@
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq.Expressions;
+using System.Xml;
+using System.Xml.Serialization;
+using Bonsai.Dag;
+
+namespace Bonsai.Expressions
+{
+    /// <summary>
+    /// Represents a written explanation or critical comment added to the workflow.
+    /// </summary>
+    [DefaultProperty(nameof(Name))]
+    [WorkflowElementCategory(ElementCategory.Property)]
+    [XmlType("Annotation", Namespace = Constants.XmlNamespace)]
+    [Editor("Bonsai.Design.AnnotationBuilderEditor, Bonsai.Design", typeof(ComponentEditor))]
+    [Description("Represents a written explanation or critical comment added to the workflow.")]
+    public class AnnotationBuilder : ExpressionBuilder, INamedElement, IArgumentBuilder
+    {
+        static readonly XmlDocument cdataFactory = new XmlDocument();
+        static readonly Range<int> argumentRange = Range.Create(lowerBound: 0, upperBound: 0);
+
+        /// <summary>
+        /// Gets or sets the name of the annotation node in the workflow.
+        /// </summary>
+        [Externalizable(false)]
+        [Category(nameof(CategoryAttribute.Design))]
+        [Description("The name of the annotation node in the workflow.")]
+        public string Name { get; set; }
+
+        /// <summary>
+        /// Gets or sets the text associated with this annotation.
+        /// </summary>
+        [XmlIgnore]
+        [Externalizable(false)]
+        [Category(nameof(CategoryAttribute.Design))]
+        [Description("The text associated with this annotation.")]
+        public string Text { get; set; }
+
+        /// <summary>
+        /// Gets or sets a CDATA section representing the annotation for serialization.
+        /// </summary>
+        [Browsable(false)]
+        [XmlElement(nameof(Text))]
+        public XmlCDataSection TextCData
+        {
+            get { return cdataFactory.CreateCDataSection(Text); }
+            set { Text = value?.Data; }
+        }
+
+        /// <inheritdoc/>
+        public override Range<int> ArgumentRange => argumentRange;
+
+        /// <inheritdoc/>
+        public override Expression Build(IEnumerable<Expression> arguments)
+        {
+            return EmptyExpression.Instance;
+        }
+
+        bool IArgumentBuilder.BuildArgument(Expression source, Edge<ExpressionBuilder, ExpressionBuilderArgument> successor, out Expression argument)
+        {
+            argument = source;
+            return false;
+        }
+    }
+}

Bonsai.Design/AnnotationBuilderEditor.cs

@@ -0,0 +1,35 @@
+using System;
+using System.ComponentModel;
+using System.Windows.Forms;
+using Bonsai.Expressions;
+
+namespace Bonsai.Design
+{
+    /// <summary>
+    /// Provides a user interface editor that displays a dialog box for editing
+    /// a workflow annotation.
+    /// </summary>
+    public class AnnotationBuilderEditor : WorkflowComponentEditor
+    {
+        /// <inheritdoc/>
+        public override bool EditComponent(ITypeDescriptorContext context, object component, IServiceProvider provider, IWin32Window owner)
+        {
+            if (provider != null)
+            {
+                var editorState = (IWorkflowEditorState)provider.GetService(typeof(IWorkflowEditorState));
+                if (editorState != null && !editorState.WorkflowRunning && component is AnnotationBuilder annotationBuilder)
+                {
+                    using var editorDialog = new AnnotationBuilderEditorDialog();
+                    editorDialog.Annotation = annotationBuilder.Text;
+                    if (editorDialog.ShowDialog(owner) == DialogResult.OK)
+                    {
+                        annotationBuilder.Text = editorDialog.Annotation;
+                    }
+                    return true;
+                }
+            }
+
+            return false;
+        }
+    }
+}

Bonsai.Design/AnnotationBuilderEditorDialog.cs

@@ -0,0 +1,88 @@
+using ScintillaNET;
+using System;
+using System.Drawing;
+using System.Windows.Forms;
+
+namespace Bonsai.Design
+{
+    internal partial class AnnotationBuilderEditorDialog : Form
+    {
+        public AnnotationBuilderEditorDialog()
+        {
+            InitializeComponent();
+            scintilla.StyleResetDefault();
+            scintilla.Styles[Style.Default].Font = "Consolas";
+            scintilla.Styles[Style.Default].Size = 10;
+            scintilla.StyleClearAll();
+
+            scintilla.CaretLineBackColor = ColorTranslator.FromHtml("#feefff");
+            scintilla.Styles[Style.Markdown.Default].ForeColor = Color.Black;
+            scintilla.Styles[Style.Markdown.Link].Underline = true;
+            scintilla.Styles[Style.Markdown.Em1].Italic = true;
+            scintilla.Styles[Style.Markdown.Em2].Italic = true;
+            scintilla.Styles[Style.Markdown.Strong1].Bold = true;
+            scintilla.Styles[Style.Markdown.Strong2].Bold = true;
+            scintilla.Styles[Style.Markdown.Header1].Bold = true;
+            scintilla.Styles[Style.Markdown.Header2].Bold = true;
+            scintilla.Styles[Style.Markdown.Header3].Bold = true;
+            scintilla.Styles[Style.Markdown.Header4].Bold = true;
+            scintilla.Styles[Style.Markdown.Header5].Bold = true;
+            scintilla.Styles[Style.Markdown.Header6].Bold = true;
+            scintilla.Styles[Style.Markdown.Strong1].ForeColor = ColorTranslator.FromHtml("#2b91af");
+            scintilla.Styles[Style.Markdown.Strong2].ForeColor = ColorTranslator.FromHtml("#2b91af");
+            scintilla.Styles[Style.Markdown.Header1].ForeColor = ColorTranslator.FromHtml("#2b91af");
+            scintilla.Styles[Style.Markdown.Header2].ForeColor = ColorTranslator.FromHtml("#2b91af");
+            scintilla.Styles[Style.Markdown.Header3].ForeColor = ColorTranslator.FromHtml("#2b91af");
+            scintilla.Styles[Style.Markdown.Header4].ForeColor = ColorTranslator.FromHtml("#2b91af");
+            scintilla.Styles[Style.Markdown.Header5].ForeColor = ColorTranslator.FromHtml("#2b91af");
+            scintilla.Styles[Style.Markdown.Header6].ForeColor = ColorTranslator.FromHtml("#2b91af");
+            scintilla.Styles[Style.Markdown.UListItem].ForeColor = ColorTranslator.FromHtml("#2b91af");
+            scintilla.Styles[Style.Markdown.OListItem].ForeColor = ColorTranslator.FromHtml("#2b91af");
+            scintilla.Styles[Style.Markdown.HRule].ForeColor = ColorTranslator.FromHtml("#2b91af");
+            scintilla.Styles[Style.Markdown.Code].ForeColor = ColorTranslator.FromHtml("#a31515");
+            scintilla.Styles[Style.Markdown.Code2].ForeColor = ColorTranslator.FromHtml("#a31515");
+            scintilla.Styles[Style.Markdown.CodeBk].ForeColor = ColorTranslator.FromHtml("#a31515");
+            scintilla.Styles[Style.Markdown.BlockQuote].ForeColor = ColorTranslator.FromHtml("#a31515");
+            scintilla.Lexer = Lexer.Markdown;
+        }
+
+        public string Annotation { get; set; }
+
+        protected override void OnLoad(EventArgs e)
+        {
+            scintilla.Text = Annotation;
+            scintilla.EmptyUndoBuffer();
+            if (Owner != null)
+            {
+                Icon = Owner.Icon;
+                ShowIcon = true;
+            }
+
+            base.OnLoad(e);
+        }
+
+        protected override void OnKeyDown(KeyEventArgs e)
+        {
+            if (e.KeyCode == Keys.Escape && !e.Handled)
+            {
+                Close();
+                e.Handled = true;
+            }
+
+            base.OnKeyDown(e);
+        }
+
+        private void scintilla_KeyDown(object sender, KeyEventArgs e)
+        {
+            if (e.KeyCode == Keys.Enter && e.Modifiers == Keys.Control)
+            {
+                okButton.PerformClick();
+            }
+        }
+
+        private void scintilla_TextChanged(object sender, EventArgs e)
+        {
+            Annotation = scintilla.Text;
+        }
+    }
+}