CreateSimplePDF.cs

using System;
using System.IO;
using System.Text;
using FluentAssertions;
using PdfSharpCore.Drawing;
using PdfSharpCore.Pdf;
using PdfSharpCore.Test.Helpers;
using PdfSharpCore.Utils;
using SkiaSharp;
using Xunit;

namespace PdfSharpCore.Test
{
    public class CreateSimplePdf
    {
        private readonly string _rootPath = PathHelper.GetInstance().RootDir;
        private const string OutputDirName = "Out";

        [Fact]
        public void CreateTestPdf()
        {
            const string outName = "test1.pdf";

            ValidateTargetAvailable(outName);

            var document = new PdfDocument();

            var pageNewRenderer = document.AddPage();

            var renderer = XGraphics.FromPdfPage(pageNewRenderer);

            renderer.DrawString("Testy Test Test", new XFont("Arial", 12), XBrushes.Black, new XPoint(12, 12));

            SaveDocument(document, outName);
            ValidateFileIsPdf(outName);
        }

        [Fact]
        public void CreateTestPdfWithUnicodeMetadata()
        {
            const string data = "English, Ελληνικά, 漢語";

            var document = new PdfDocument();
            document.Info.Title = data;
            document.Info.Subject = data;
            document.Info.Author = data;

            using var ms = new MemoryStream();
            document.AddPage();
            document.Save(ms);
            ms.Position = 0;

            PdfDocument generatedDocument = Pdf.IO.PdfReader.Open(ms);

            Assert.Equal(data, generatedDocument.Info.Title);
            Assert.Equal(data, generatedDocument.Info.Subject);
            Assert.Equal(data, generatedDocument.Info.Author);
        }

        [Fact]
        public void CreateTestPdfWithImage()
        {
            using var stream = new MemoryStream();
            var document = new PdfDocument();

            var pageNewRenderer = document.AddPage();

            var renderer = XGraphics.FromPdfPage(pageNewRenderer);

            renderer.DrawImage(XImage.FromFile(PathHelper.GetInstance().GetAssetPath("lenna.png")), new XPoint(0, 0));

            document.Save(stream);
            stream.Position = 0;
            Assert.True(stream.Length > 1);
            ReadStreamAndVerifyPdfHeaderSignature(stream);
        }

        [Fact]
        public void CreateTestPdfWithImageViaSkiaSharp()
        {
            using var stream = new MemoryStream();
            var document = new PdfDocument();

            var pageNewRenderer = document.AddPage();

            var renderer = XGraphics.FromPdfPage(pageNewRenderer);

            // Load image with SkiaSharp and apply a simple grayscale filter:
            var bitmap = SKBitmap.Decode(PathHelper.GetInstance().GetAssetPath("lenna.png"));
            var grayInfo = new SKImageInfo(bitmap.Width, bitmap.Height, SKColorType.Bgra8888, SKAlphaType.Premul);
            var gray = new SKBitmap(grayInfo);
            using (var canvas = new SKCanvas(gray))
            using (var paint = new SKPaint())
            {
                paint.ColorFilter = SKColorFilter.CreateColorMatrix(new float[]
                {
                    0.2126f, 0.7152f, 0.0722f, 0, 0,
                    0.2126f, 0.7152f, 0.0722f, 0, 0,
                    0.2126f, 0.7152f, 0.0722f, 0, 0,
                    0,       0,       0,       1, 0
                });
                canvas.DrawBitmap(bitmap, 0, 0, paint);
            }
            bitmap.Dispose();

            // create XImage from that same SkiaSharp bitmap:
            var source = SkiaSharpImageSource.FromBitmap(gray);
            var img = XImage.FromImageSource(source);

            renderer.DrawImage(img, new XPoint(0, 0));

            document.Save(stream);
            stream.Position = 0;
            Assert.True(stream.Length > 1);
            ReadStreamAndVerifyPdfHeaderSignature(stream);
        }

        private void SaveDocument(PdfDocument document, string name)
        {
            var outFilePath = GetOutFilePath(name);
            var dir = Path.GetDirectoryName(outFilePath);
            if (!Directory.Exists(dir))
            {
                Directory.CreateDirectory(dir);
            }

            document.Save(outFilePath);
        }

        private void ValidateFileIsPdf(string v)
        {
            var path = GetOutFilePath(v);
            Assert.True(File.Exists(path));
            var fi = new FileInfo(path);
            Assert.True(fi.Length > 1);

            using var stream = File.OpenRead(path);
            ReadStreamAndVerifyPdfHeaderSignature(stream);
        }

        private static void ReadStreamAndVerifyPdfHeaderSignature(Stream stream)
        {
            var readBuffer = new byte[5];
            var pdfSignature = Encoding.ASCII.GetBytes("%PDF-"); // PDF must start with %PDF-

            stream.Read(readBuffer, 0, readBuffer.Length);
            readBuffer.Should().Equal(pdfSignature);
        }

        private void ValidateTargetAvailable(string file)
        {
            var path = GetOutFilePath(file);
            if (File.Exists(path))
            {
                File.Delete(path);
            }

            Assert.False(File.Exists(path));
        }

        private string GetOutFilePath(string name)
        {
            return Path.Combine(_rootPath, OutputDirName, name);
        }
    }
}