SpellerHighlightLayer.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / System / Windows / Documents / SpellerHighlightLayer.cs / 1305600 / SpellerHighlightLayer.cs
                        
                        
                            //---------------------------------------------------------------------------- 
//
// File: SpellerHighlightLayer.cs
//
// Description: Highlight rendering for the Speller. 
//
//--------------------------------------------------------------------------- 
 
using System;
using MS.Internal; 
using System.Windows.Documents;
using System.Windows.Media;
using System.Collections;
using System.Collections.Generic; 
using System.Collections.ObjectModel;
 
namespace System.Windows.Documents 
{
    // Highlight rendering for the Speller. 
    // The speller tags errors with red squigglies.
    internal class SpellerHighlightLayer : HighlightLayer
    {
        //----------------------------------------------------- 
        //
        //  Constructors 
        // 
        //-----------------------------------------------------
 
        #region Constructors

        // Static constructor.
        static SpellerHighlightLayer() 
        {
            _errorTextDecorations = GetErrorTextDecorations(); 
        } 

        // Constructor. 
        internal SpellerHighlightLayer(Speller speller)
        {
            _speller = speller;
        } 

        #endregion Constructors 
 
        //------------------------------------------------------
        // 
        //  Internal Methods
        //
        //-----------------------------------------------------
 
        #region Internal Methods
 
        // Returns a TextDecorationCollection used to tag spelling errors, 
        // or DependencyProperty.UnsetValue if there's no error at the specified position.
        internal override object GetHighlightValue(StaticTextPointer textPosition, LogicalDirection direction) 
        {
            object value;

            if (IsContentHighlighted(textPosition, direction)) 
            {
                value = _errorTextDecorations; 
            } 
            else
            { 
                value = DependencyProperty.UnsetValue;
            }

            return value; 
        }
 
        // Returns true iff the indicated content has scoping highlights. 
        internal override bool IsContentHighlighted(StaticTextPointer textPosition, LogicalDirection direction)
        { 
            return _speller.StatusTable.IsRunType(textPosition, direction, SpellerStatusTable.RunType.Error);
        }

        // Returns the position of the next highlight start or end in an 
        // indicated direction, or null if there is no such position.
        internal override StaticTextPointer GetNextChangePosition(StaticTextPointer textPosition, LogicalDirection direction) 
        { 
            return _speller.StatusTable.GetNextErrorTransition(textPosition, direction);
        } 

        // Raises a Changed event for any listeners, covering the
        // specified text.
        internal void FireChangedEvent(ITextPointer start, ITextPointer end) 
        {
            if (Changed != null) 
            { 
                Changed(this, new SpellerHighlightChangedEventArgs(start, end));
            } 
        }

        #endregion Internal Methods
 
        //------------------------------------------------------
        // 
        //  Internal Properties 
        //
        //------------------------------------------------------ 

        #region Internal Properties

        // Type identifying this layer for Highlights.GetHighlightValue calls. 
        internal override Type OwnerType
        { 
            get 
            {
                return typeof(SpellerHighlightLayer); 
            }
        }

        #endregion Internal Properties 

        //----------------------------------------------------- 
        // 
        //  Internal Events
        // 
        //------------------------------------------------------

        #region Internal Events
 
        /// 
        /// Event raised when a highlight range is inserted, removed, moved, or 
        /// has a local property value change. 
        /// 
        internal override event HighlightChangedEventHandler Changed; 

        #endregion Internal Events

        //----------------------------------------------------- 
        //
        //  Private Methods 
        // 
        //-----------------------------------------------------
 
        #region Private Methods

        // Calculates TextDecorations for speller errors.
        private static TextDecorationCollection GetErrorTextDecorations() 
        {
            // 
            // Build a "squiggle" Brush. 
            //
            // This works by hard-coding a 3 pixel high TextDecoration, and 
            // then tiling horizontally.  (We can't scale the squiggle in
            // the vertical direction, there's no support to limit tiling
            // to just the horizontal from the MIL.)
            // 

            DrawingGroup drawingGroup = new DrawingGroup(); 
            DrawingContext drawingContext = drawingGroup.Open(); 
            Pen pen = new Pen(Brushes.Red, 0.33);
 
            // This is our tile:
            //
            //  x   x
            //   x x 
            //    x
            // 
            drawingContext.DrawLine(pen, new Point(0.0, 0.0), new Point(0.5, 1.0)); 
            drawingContext.DrawLine(pen, new Point(0.5, 1.0), new Point(1.0, 0.0));
 
            drawingContext.Close();

            DrawingBrush brush = new DrawingBrush(drawingGroup);
            brush.TileMode = TileMode.Tile; 
            brush.Viewport = new Rect(0, 0, 3, 3);
            brush.ViewportUnits = BrushMappingMode.Absolute; 
 
            TextDecoration textDecoration = new TextDecoration(
                            TextDecorationLocation.Underline, 
                            new Pen(brush, 3),
                            0,
                            TextDecorationUnit.FontRecommended,
                            TextDecorationUnit.Pixel); 

            TextDecorationCollection decorationCollection = new TextDecorationCollection(); 
            decorationCollection.Add(textDecoration); 

            decorationCollection.Freeze(); 

            return decorationCollection;
        }
 
        #endregion Private Methods
 
        //----------------------------------------------------- 
        //
        //  Private Types 
        //
        //------------------------------------------------------

        #region Private Types 

        // Argument for the Changed event, encapsulates a highlight change. 
        private class SpellerHighlightChangedEventArgs : HighlightChangedEventArgs 
        {
            // Constructor. 
            internal SpellerHighlightChangedEventArgs(ITextPointer start, ITextPointer end)
            {
                List list;
 
                Invariant.Assert(start.CompareTo(end) < 0, "Bogus start/end combination!");
 
                list = new List(1); 
                list.Add(new TextSegment(start, end));
 
                _ranges = new ReadOnlyCollection(list);
            }

            // Collection of changed content ranges. 
            internal override IList Ranges
            { 
                get 
                {
                    return _ranges; 
                }
            }

            // Type identifying the owner of the changed layer. 
            internal override Type OwnerType
            { 
                get 
                {
                    return typeof(SpellerHighlightLayer); 
                }
            }

            // Collection of changed content ranges. 
            private readonly ReadOnlyCollection _ranges;
        } 
 
        #endregion Private Types
 
        //-----------------------------------------------------
        //
        //  Private Fields
        // 
        //------------------------------------------------------
 
        #region Private Fields 

        // Assocated Speller. 
        private readonly Speller _speller;

        // Decorations for text flagged with a spelling error.
        private static readonly TextDecorationCollection _errorTextDecorations; 

        #endregion Private Fields 
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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SpellerHighlightLayer.cs source code in C# .NET

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