source: trunk/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Rendering/VisualLineLinkText.cs @ 17530

// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Windows;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.TextFormatting;
using System.Windows.Navigation;

namespace ICSharpCode.AvalonEdit.Rendering
{
  /// <summary>
  /// VisualLineElement that represents a piece of text and is a clickable link.
  /// </summary>
  public class VisualLineLinkText : VisualLineText
  {
    /// <summary>
    /// Gets/Sets the URL that is navigated to when the link is clicked.
    /// </summary>
    public Uri NavigateUri { get; set; }
    
    /// <summary>
    /// Gets/Sets the window name where the URL will be opened.
    /// </summary>
    public string TargetName { get; set; }
    
    /// <summary>
    /// Gets/Sets whether the user needs to press Control to click the link.
    /// The default value is true.
    /// </summary>
    public bool RequireControlModifierForClick { get; set; }
    
    /// <summary>
    /// Creates a visual line text element with the specified length.
    /// It uses the <see cref="ITextRunConstructionContext.VisualLine"/> and its
    /// <see cref="VisualLineElement.RelativeTextOffset"/> to find the actual text string.
    /// </summary>
    public VisualLineLinkText(VisualLine parentVisualLine, int length) : base(parentVisualLine, length)
    {
      this.RequireControlModifierForClick = true;
    }
    
    /// <inheritdoc/>
    public override TextRun CreateTextRun(int startVisualColumn, ITextRunConstructionContext context)
    {
      this.TextRunProperties.SetForegroundBrush(context.TextView.LinkTextForegroundBrush);
      this.TextRunProperties.SetBackgroundBrush(context.TextView.LinkTextBackgroundBrush);
      this.TextRunProperties.SetTextDecorations(TextDecorations.Underline);
      return base.CreateTextRun(startVisualColumn, context);
    }
    
    /// <summary>
    /// Gets whether the link is currently clickable.
    /// </summary>
    /// <remarks>Returns true when control is pressed; or when
    /// <see cref="RequireControlModifierForClick"/> is disabled.</remarks>
    protected bool LinkIsClickable()
    {
      if (NavigateUri == null)
        return false;
      if (RequireControlModifierForClick)
        return (Keyboard.Modifiers & ModifierKeys.Control) == ModifierKeys.Control;
      else
        return true;
    }
    
    /// <inheritdoc/>
    protected internal override void OnQueryCursor(QueryCursorEventArgs e)
    {
      if (LinkIsClickable()) {
        e.Handled = true;
        e.Cursor = Cursors.Hand;
      }
    }
    
    /// <inheritdoc/>
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes",
                                                     Justification = "I've seen Process.Start throw undocumented exceptions when the mail client / web browser is installed incorrectly")]
    protected internal override void OnMouseDown(MouseButtonEventArgs e)
    {
      if (e.ChangedButton == MouseButton.Left && !e.Handled && LinkIsClickable()) {
        RequestNavigateEventArgs args = new RequestNavigateEventArgs(this.NavigateUri, this.TargetName);
        args.RoutedEvent = Hyperlink.RequestNavigateEvent;
        FrameworkElement element = e.Source as FrameworkElement;
        if (element != null) {
          // allow user code to handle the navigation request
          element.RaiseEvent(args);
        }
        if (!args.Handled) {
          try {
            Process.Start(this.NavigateUri.ToString());
          } catch {
            // ignore all kinds of errors during web browser start
          }
        }
        e.Handled = true;
      }
    }
    
    /// <inheritdoc/>
    protected override VisualLineText CreateInstance(int length)
    {
      return new VisualLineLinkText(ParentVisualLine, length) {
        NavigateUri = this.NavigateUri,
        TargetName = this.TargetName,
        RequireControlModifierForClick = this.RequireControlModifierForClick
      };
    }
  }
}