using System;
using DocumentFormat.OpenXml;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Presentation;
using D = DocumentFormat.OpenXml.Drawing;

var outputPath = @"C:\Users\Administrator\Desktop\test_slides.pptx";

using var presentation = PresentationDocument.Create(outputPath, PresentationDocumentType.Presentation);
var presPart = presentation.AddPresentationPart();
presPart.Presentation = new Presentation();

var slideIdList = new SlideIdList();
presPart.Presentation.SlideIdList = slideIdList;
presPart.Presentation.SlideSize = new SlideSize { Cx = 12192000, Cy = 6858000 };

var slideMasterPart = presPart.AddNewPart<SlideMasterPart>();
var slideLayoutPart = slideMasterPart.AddNewPart<SlideLayoutPart>();
slideLayoutPart.SlideLayout = new SlideLayout(new CommonSlideData(new ShapeTree()));
slideLayoutPart.SlideLayout.Save();

slideMasterPart.SlideMaster = new SlideMaster(
    new CommonSlideData(new ShapeTree()),
    new SlideLayoutIdList(new SlideLayoutId
    {
        RelationshipId = slideMasterPart.GetIdOfPart(slideLayoutPart)
    }));
slideMasterPart.SlideMaster.Save();

// Slide 1
var slidePart1 = presPart.AddNewPart<SlidePart>();
slidePart1.Slide = new Slide(new CommonSlideData(new ShapeTree(
    MakeTextShape(1, "Title", 500000, 500000, 10000000, 800000, 4400, true, "Hello, Better-Seewo!"),
    MakeTextShape(2, "Subtitle", 500000, 2000000, 10000000, 600000, 2800, false, "PPTX to ENBX conversion test"))));
slidePart1.Slide.Save();
slideIdList.Append(new SlideId { Id = 256, RelationshipId = presPart.GetIdOfPart(slidePart1) });

// Slide 2
var slidePart2 = presPart.AddNewPart<SlidePart>();
slidePart2.Slide = new Slide(new CommonSlideData(new ShapeTree(
    MakeTextShape(1, "Title", 500000, 500000, 10000000, 800000, 3600, true, "Slide 2"),
    MakeTextShape(2, "Body", 500000, 2000000, 10000000, 1000000, 2200, false, "Second slide with more content"))));
slidePart2.Slide.Save();
slideIdList.Append(new SlideId { Id = 257, RelationshipId = presPart.GetIdOfPart(slidePart2) });

presPart.Presentation.Save();
Console.WriteLine($"Created: {outputPath}");

static Shape MakeTextShape(uint id, string name, long x, long y, long cx, long cy, int fontSize, bool bold, string text)
{
    return new Shape(
        new NonVisualShapeProperties(
            new NonVisualDrawingProperties { Id = id, Name = name },
            new NonVisualShapeDrawingProperties()),
        new ShapeProperties(
            new D.Transform2D(
                new D.Offset { X = x, Y = y },
                new D.Extents { Cx = cx, Cy = cy })),
        new TextBody(
            new D.BodyProperties(),
            new D.ListStyle(),
            new D.Paragraph(
                new D.Run(
                    new D.RunProperties { FontSize = fontSize, Bold = bold },
                    new D.Text(text)))));
}