ParagraphVisual.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Framework / MS / Internal / PtsHost / ParagraphVisual.cs / 1 / ParagraphVisual.cs
                        
                        
                            //---------------------------------------------------------------------------- 
//
// Copyright (C) Microsoft Corporation.  All rights reserved.
//
// File: ParagraphVisaul.cs 
//
// Description: Visual representing a paragraph. 
// 
// History:
//  05/20/2003 : [....] - created. 
//
//---------------------------------------------------------------------------

using System; 
using System.Windows;
using System.Windows.Media; 
 
namespace MS.Internal.PtsHost
{ 
    /// 
    /// Visual representing a paragraph.
    /// 
    internal class ParagraphVisual : DrawingVisual 
    {
        ///  
        /// Constructor. 
        /// 
        internal ParagraphVisual() 
        {
            _renderBounds = Rect.Empty;
        }
 
        /// 
        /// Draw background and border. 
        ///  
        /// The brush used for background.
        /// The brush used for border. 
        /// Border thickness.
        /// Render bounds of the visual.
        /// Whether this is paragraph's first chunk.
        /// Whether this is paragraph's last chunk. 
        internal void DrawBackgroundAndBorder(Brush backgroundBrush, Brush borderBrush, Thickness borderThickness, Rect renderBounds, bool isFirstChunk, bool isLastChunk)
        { 
            if (_backgroundBrush != backgroundBrush || _renderBounds != renderBounds || 
                _borderBrush != borderBrush || !Thickness.AreClose(_borderThickness, borderThickness))
            { 
                // Open DrawingContext and draw background.
                using (DrawingContext dc = RenderOpen())
                {
                    DrawBackgroundAndBorderIntoContext(dc, backgroundBrush, borderBrush, borderThickness, renderBounds, isFirstChunk, isLastChunk); 
                }
            } 
        } 

 
        /// 
        /// Draw background and border.
        /// 
        /// Drawing context. 
        /// The brush used for background.
        /// The brush used for border. 
        /// Border thickness. 
        /// Render bounds of the visual.
        /// Whether this is paragraph's first chunk. 
        /// Whether this is paragraph's last chunk.
        internal void DrawBackgroundAndBorderIntoContext(DrawingContext dc, Brush backgroundBrush, Brush borderBrush, Thickness borderThickness, Rect renderBounds, bool isFirstChunk, bool isLastChunk)
        {
            // We do not want to cause the user's Brushes to become frozen when we 
            // freeze the Pen in OnRender, therefore we make our own copy of the
            // Brushes if they are not already frozen. 
            _backgroundBrush = (Brush)FreezableOperations.GetAsFrozenIfPossible(backgroundBrush); 
            _renderBounds = renderBounds;
            _borderBrush = (Brush)FreezableOperations.GetAsFrozenIfPossible(borderBrush); 
            _borderThickness = borderThickness;

            // Exclude top/bottom border if this is not the first/last chunk of the paragraph.
            if (!isFirstChunk) 
            {
                _borderThickness.Top = 0.0; 
            } 
            if (!isLastChunk)
            { 
                _borderThickness.Bottom = 0.0;
            }

            // If we have a brush with which to draw the border, do so. 
            // NB: We double draw corners right now.  Corner handling is tricky (bevelling, &c...) and
            //     we need a firm spec before doing "the right thing."  ([....], ffortes) 
            if (_borderBrush != null) 
            {
                // Initialize the first pen.  Note that each pen is created via new() 
                // and frozen if possible.  Doing this avoids the overhead of
                // maintaining changed handlers.
                Pen pen = new Pen();
                pen.Brush = _borderBrush; 
                pen.Thickness = _borderThickness.Left;
                if (pen.CanFreeze) { pen.Freeze(); } 
 
                if (_borderThickness.IsUniform)
                { 
                    // Uniform border; stroke a rectangle.
                    dc.DrawRectangle(null, pen, new Rect(
                        new Point(_renderBounds.Left + pen.Thickness * 0.5, _renderBounds.Bottom - pen.Thickness * 0.5),
                        new Point(_renderBounds.Right - pen.Thickness * 0.5, _renderBounds.Top + pen.Thickness * 0.5))); 
                }
                else 
                { 
                    if (DoubleUtil.GreaterThan(_borderThickness.Left, 0))
                    { 
                        dc.DrawLine(pen,
                            new Point(_renderBounds.Left + pen.Thickness / 2, _renderBounds.Top),
                            new Point(_renderBounds.Left + pen.Thickness / 2, _renderBounds.Bottom));
                    } 
                    if (DoubleUtil.GreaterThan(_borderThickness.Right, 0))
                    { 
                        pen = new Pen(); 
                        pen.Brush = _borderBrush;
                        pen.Thickness = _borderThickness.Right; 
                        if (pen.CanFreeze) { pen.Freeze(); }

                        dc.DrawLine(pen,
                            new Point(_renderBounds.Right - pen.Thickness / 2, _renderBounds.Top), 
                            new Point(_renderBounds.Right - pen.Thickness / 2, _renderBounds.Bottom));
                    } 
                    if (DoubleUtil.GreaterThan(_borderThickness.Top, 0)) 
                    {
                        pen = new Pen(); 
                        pen.Brush = _borderBrush;
                        pen.Thickness = _borderThickness.Top;
                        if (pen.CanFreeze) { pen.Freeze(); }
 
                        dc.DrawLine(pen,
                            new Point(_renderBounds.Left, _renderBounds.Top + pen.Thickness / 2), 
                            new Point(_renderBounds.Right, _renderBounds.Top + pen.Thickness / 2)); 
                    }
                    if (DoubleUtil.GreaterThan(_borderThickness.Bottom, 0)) 
                    {
                        pen = new Pen();
                        pen.Brush = _borderBrush;
                        pen.Thickness = _borderThickness.Bottom; 
                        if (pen.CanFreeze) { pen.Freeze(); }
 
                        dc.DrawLine(pen, 
                            new Point(_renderBounds.Left, _renderBounds.Bottom - pen.Thickness / 2),
                            new Point(_renderBounds.Right, _renderBounds.Bottom - pen.Thickness / 2)); 
                    }
                }
            }
 

            // Draw background in rectangle inside border. 
            if (_backgroundBrush != null) 
            {
                dc.DrawRectangle(_backgroundBrush, null, 
                    new Rect(
                        new Point(_renderBounds.Left + _borderThickness.Left, _renderBounds.Top + _borderThickness.Top),
                        new Point(_renderBounds.Right - _borderThickness.Right, _renderBounds.Bottom - _borderThickness.Bottom)));
            } 
        }
 
        private Brush _backgroundBrush;         // Background brush 
        private Brush _borderBrush;             // Border brush
        private Thickness _borderThickness;     // Border thickness 
        private Rect _renderBounds;             // Render bounds of the visual
    }
}

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

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