Реализация обводки в PDF с помощью C# и .NET

using System;
using SautinSoft.Pdf;
using System.IO;
using SautinSoft.Pdf.Content;

class Program
{
    /// <summary>
    /// Stroking
    /// </summary>
    /// <remarks>
    /// Details: https://sautinsoft.com/products/pdf/help/net/developer-guide/pdf-content-formatting-stroking.php
    /// </remarks>
    static void Main()
    {
        // Before starting this example, please get a free trial key:
        // https://sautinsoft.com/start-for-free/

        // Apply the key here:
        // PdfDocument.SetLicense("...");

        using (var document = new PdfDocument())
        {
            var page = document.Pages.Add();

            // PdfFormattedText currently doesn't support stroking, so we will stroke its drawn output.
            using (var formattedText = new PdfFormattedText())
            {
                formattedText.Font = new PdfFont("Helvetica", 200);

                formattedText.Append("Hello!");

                page.Content.DrawText(formattedText, new PdfPoint(50, 600));
            }

            // Draw lines with different line joins.
            var path = page.Content.Elements.AddPath();
            path.BeginSubpath(50, 350).LineTo(100, 550).LineTo(150, 350);
            path.Format.Stroke.LineJoin = PdfLineJoin.Miter;

            path = page.Content.Elements.AddPath();
            path.BeginSubpath(200, 350).LineTo(250, 550).LineTo(300, 350);
            path.Format.Stroke.LineJoin = PdfLineJoin.Round;

            path = page.Content.Elements.AddPath();
            path.BeginSubpath(350, 350).LineTo(400, 550).LineTo(450, 350);
            path.Format.Stroke.LineJoin = PdfLineJoin.Bevel;

            // Create a dash pattern with 20 point dashes and 10 point gaps.
            var dashPattern = new PdfLineDashPattern(0, 20, 10);

            // Draw lines with different line caps.
            // Notice how the line cap is applied to each dash.
            path = page.Content.Elements.AddPath();
            path.BeginSubpath(50, 100).LineTo(100, 300).LineTo(150, 100);
            var format = path.Format;
            format.Stroke.LineCap = PdfLineCap.Butt;
            format.Stroke.DashPattern = dashPattern;

            path = page.Content.Elements.AddPath();
            path.BeginSubpath(200, 100).LineTo(250, 300).LineTo(300, 100);
            format = path.Format;
            format.Stroke.LineCap = PdfLineCap.Round;
            format.Stroke.DashPattern = dashPattern;

            path = page.Content.Elements.AddPath();
            path.BeginSubpath(350, 100).LineTo(400, 300).LineTo(450, 100);
            format = path.Format;
            format.Stroke.LineCap = PdfLineCap.Square;
            format.Stroke.DashPattern = dashPattern;

            // Do not fill any content and stroke all content with a 10 point width red outline that is 50% opaque.
            format = page.Content.Format;
            format.Fill.IsApplied = false;
            format.Stroke.IsApplied = true;
            format.Stroke.Width = 10;
            format.Stroke.Color = PdfColor.FromRgb(1, 0, 0);
            format.Stroke.Opacity = 0.5;

            // Add a line to visualize the differences between line joins.
            var line = page.Content.Elements.AddPath().BeginSubpath(25, 550).LineTo(475, 550);
            format = line.Format;
            format.Stroke.IsApplied = true;
            // A line width of 0 denotes the thinnest line that can be rendered at device resolution: 1 device pixel wide.
            format.Stroke.Width = 0;

            // Add a line to visualize the differences between line caps.
            line = page.Content.Elements.AddPath().BeginSubpath(25, 100).LineTo(475, 100);
            format = line.Format;
            format.Stroke.IsApplied = true;
            format.Stroke.Width = 0;

            document.Save("Stroking.pdf");
        }

        System.Diagnostics.Process.Start(new System.Diagnostics.ProcessStartInfo("Stroking.pdf") { UseShellExecute = true });
    }
}

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