astel-labs.net

結構前に WPF で文字の縁取りについて話題にしたことがありましたが、その後 MSDN のサンプルコードを基に私なりに実装を行って利用していたのですが、つい最近海外のサイトを巡っていた際、スマートな方法で文字の縁取りをしているサンプルコードを見つけたため紹介します

（アクセス解析でも、検索ワードが「縁取り」でこのサイトに来る方が意外と多いようでした）

ちなみに、サンプルを実行すると以下のようになります

文字列表示の xaml コードです
縁取りの太さは StrokeThickness、縁取りの色は Stroke、文字色は Fill で指定します
フォントの情報は Font～ 関連プロパティで指定します

<Window x:Class="OutlineFont.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:OutlineFont"
        Title="MainWindow" Height="160" Width="402">
    <Grid>
        <local:OutlineText FontFamily="Verdana" FontSize="50" FontWeight="ExtraBold" TextWrapping="Wrap"
                           StrokeThickness="3" Stroke="Red" Fill="Yellow"
                           Text="Hello world!" />
    </Grid>
</Window>

で、文字列縁取り用のコードが以下になります
例によって GW の最終日でいろいろと疲れて眠いため、説明は省略です。。。

using System;
using System.ComponentModel;
using System.Globalization;
using System.Windows;
using System.Windows.Documents;
using System.Windows.Markup;
using System.Windows.Media;

namespace OutlineFont
{
    [ContentProperty( "Text" )]
    internal class OutlineText : FrameworkElement
    {
        private FormattedText FormattedText;
        private Geometry TextGeometry;

        public static readonly DependencyProperty TextProperty = DependencyProperty.Register(
            "Text", typeof( string ), typeof( OutlineText ),
            new FrameworkPropertyMetadata( OnFormattedTextInvalidated ) );

        public static readonly DependencyProperty TextAlignmentProperty = DependencyProperty.Register(
            "TextAlignment", typeof( TextAlignment ), typeof( OutlineText ),
            new FrameworkPropertyMetadata( OnFormattedTextUpdated ) );

        public static readonly DependencyProperty TextDecorationsProperty = DependencyProperty.Register(
            "TextDecorations", typeof( TextDecorationCollection ), typeof( OutlineText ),
            new FrameworkPropertyMetadata( OnFormattedTextUpdated ) );

        public static readonly DependencyProperty TextTrimmingProperty = DependencyProperty.Register(
            "TextTrimming", typeof( TextTrimming ), typeof( OutlineText ),
            new FrameworkPropertyMetadata( OnFormattedTextUpdated ) );

        public static readonly DependencyProperty TextWrappingProperty = DependencyProperty.Register(
            "TextWrapping", typeof( TextWrapping ), typeof( OutlineText ),
            new FrameworkPropertyMetadata( TextWrapping.NoWrap, OnFormattedTextUpdated ) );

        public static readonly DependencyProperty FillProperty = DependencyProperty.Register(
            "Fill", typeof( Brush ), typeof( OutlineText ),
            new FrameworkPropertyMetadata( Brushes.Red, FrameworkPropertyMetadataOptions.AffectsRender ) );

        public static readonly DependencyProperty StrokeProperty = DependencyProperty.Register(
            "Stroke", typeof( Brush ), typeof( OutlineText ),
            new FrameworkPropertyMetadata( Brushes.Black, FrameworkPropertyMetadataOptions.AffectsRender ) );

        public static readonly DependencyProperty StrokeThicknessProperty = DependencyProperty.Register(
            "StrokeThickness", typeof( double ), typeof( OutlineText ),
            new FrameworkPropertyMetadata( 1d, FrameworkPropertyMetadataOptions.AffectsRender ) );

        public static readonly DependencyProperty FontFamilyProperty = TextElement.FontFamilyProperty.AddOwner(
            typeof( OutlineText ), new FrameworkPropertyMetadata( OnFormattedTextUpdated ) );

        public static readonly DependencyProperty FontSizeProperty = TextElement.FontSizeProperty.AddOwner(
            typeof( OutlineText ), new FrameworkPropertyMetadata( OnFormattedTextUpdated ) );

        public static readonly DependencyProperty FontStretchProperty = TextElement.FontStretchProperty.AddOwner(
            typeof( OutlineText ), new FrameworkPropertyMetadata( OnFormattedTextUpdated ) );

        public static readonly DependencyProperty FontStyleProperty = TextElement.FontStyleProperty.AddOwner(
            typeof( OutlineText ), new FrameworkPropertyMetadata( OnFormattedTextUpdated ) );

        public static readonly DependencyProperty FontWeightProperty = TextElement.FontWeightProperty.AddOwner(
            typeof( OutlineText ), new FrameworkPropertyMetadata( OnFormattedTextUpdated ) );

        public OutlineText()
        {
            this.TextDecorations = new TextDecorationCollection();
        }

        public Brush Fill
        {
            get { return (Brush)GetValue( FillProperty ); }
            set { SetValue( FillProperty, value ); }
        }

        public FontFamily FontFamily
        {
            get { return (FontFamily)GetValue( FontFamilyProperty ); }
            set { SetValue( FontFamilyProperty, value ); }
        }

        [TypeConverter( typeof( FontSizeConverter ) )]
        public double FontSize
        {
            get { return (double)GetValue( FontSizeProperty ); }
            set { SetValue( FontSizeProperty, value ); }
        }

        public FontStretch FontStretch
        {
            get { return (FontStretch)GetValue( FontStretchProperty ); }
            set { SetValue( FontStretchProperty, value ); }
        }

        public FontStyle FontStyle
        {
            get { return (FontStyle)GetValue( FontStyleProperty ); }
            set { SetValue( FontStyleProperty, value ); }
        }

        public FontWeight FontWeight
        {
            get { return (FontWeight)GetValue( FontWeightProperty ); }
            set { SetValue( FontWeightProperty, value ); }
        }

        public Brush Stroke
        {
            get { return (Brush)GetValue( StrokeProperty ); }
            set { SetValue( StrokeProperty, value ); }
        }

        public double StrokeThickness
        {
            get { return (double)GetValue( StrokeThicknessProperty ); }
            set { SetValue( StrokeThicknessProperty, value ); }
        }

        public string Text
        {
            get { return (string)GetValue( TextProperty ); }
            set { SetValue( TextProperty, value ); }
        }

        public TextAlignment TextAlignment
        {
            get { return (TextAlignment)GetValue( TextAlignmentProperty ); }
            set { SetValue( TextAlignmentProperty, value ); }
        }

        public TextDecorationCollection TextDecorations
        {
            get { return (TextDecorationCollection)this.GetValue( TextDecorationsProperty ); }
            set { this.SetValue( TextDecorationsProperty, value ); }
        }

        public TextTrimming TextTrimming
        {
            get { return (TextTrimming)GetValue( TextTrimmingProperty ); }
            set { SetValue( TextTrimmingProperty, value ); }
        }

        public TextWrapping TextWrapping
        {
            get { return (TextWrapping)GetValue( TextWrappingProperty ); }
            set { SetValue( TextWrappingProperty, value ); }
        }

        protected override void OnRender( DrawingContext drawingContext )
        {
            this.EnsureGeometry();

            drawingContext.DrawGeometry( this.Fill, new Pen( this.Stroke, this.StrokeThickness ), this.TextGeometry );
        }

        protected override Size MeasureOverride( Size availableSize )
        {
            this.EnsureFormattedText();

            this.FormattedText.MaxTextWidth = Math.Min( 3579139, availableSize.Width );
            this.FormattedText.MaxTextHeight = availableSize.Height;

            return new Size( this.FormattedText.Width, this.FormattedText.Height );
        }

        protected override Size ArrangeOverride( Size finalSize )
        {
            this.EnsureFormattedText();

            this.FormattedText.MaxTextWidth = finalSize.Width;
            this.FormattedText.MaxTextHeight = finalSize.Height;

            this.TextGeometry = null;

            return finalSize;
        }

        private static void OnFormattedTextInvalidated( DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e )
        {
            var outlinedTextBlock = (OutlineText)dependencyObject;
            outlinedTextBlock.FormattedText = null;
            outlinedTextBlock.TextGeometry = null;

            outlinedTextBlock.InvalidateMeasure();
            outlinedTextBlock.InvalidateVisual();
        }

        private static void OnFormattedTextUpdated( DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e )
        {
            var outlinedTextBlock = (OutlineText)dependencyObject;
            outlinedTextBlock.UpdateFormattedText();
            outlinedTextBlock.TextGeometry = null;

            outlinedTextBlock.InvalidateMeasure();
            outlinedTextBlock.InvalidateVisual();
        }

        private void EnsureFormattedText()
        {
            if( this.FormattedText != null || this.Text == null )
                return;

            this.FormattedText = new FormattedText(
                this.Text,
                CultureInfo.CurrentUICulture,
                this.FlowDirection,
                new Typeface( this.FontFamily, this.FontStyle, this.FontWeight, FontStretches.Normal ),
                this.FontSize,
                Brushes.Black );

            this.UpdateFormattedText();
        }

        private void UpdateFormattedText()
        {
            if( this.FormattedText == null )
                return;

            this.FormattedText.MaxLineCount = this.TextWrapping == TextWrapping.NoWrap ? 1 : int.MaxValue;
            this.FormattedText.TextAlignment = this.TextAlignment;
            this.FormattedText.Trimming = this.TextTrimming;

            this.FormattedText.SetFontSize( this.FontSize );
            this.FormattedText.SetFontStyle( this.FontStyle );
            this.FormattedText.SetFontWeight( this.FontWeight );
            this.FormattedText.SetFontFamily( this.FontFamily );
            this.FormattedText.SetFontStretch( this.FontStretch );
            this.FormattedText.SetTextDecorations( this.TextDecorations );
        }

        private void EnsureGeometry()
        {
            if( this.TextGeometry != null )
                return;

            this.EnsureFormattedText();
            this.TextGeometry = this.FormattedText.BuildGeometry( new Point() );
        }
    }
}