Coming from ShapeCrawler

ShapeCrawler edits PowerPoint files through a presentation object with slides and shapes. OneDocument's Presentation is the same idea on a lossless model, with templating and PDF output, and it reads legacy .ppt. The names below follow ShapeCrawler's published documentation; its API has changed between releases, so check the release you use. Read README.md first for what is true on every page.

Open, read, save

// ShapeCrawler
var pres = new Presentation(path);
foreach (var slide in pres.Slides)
{
    foreach (var shape in slide.Shapes)
    {
        if (shape.TextFrame is { } tf) { Console.WriteLine(tf.Text); }
    }
}
 
pres.Save();

// OneDocument
using Presentation deck = Presentation.Open(path);   // .pptx, .ppsx, .potx and legacy .ppt
foreach (Slide slide in deck.Slides)
{
    foreach (Shape shape in slide.Shapes)
    {
        if (shape.TextBody is { } body) { Console.WriteLine(body.Text); }
    }
}
 
deck.Save();                                          // atomic replace; only edited parts change

Edit text

// ShapeCrawler
shape.TextFrame!.Text = "Quarterly results";

// OneDocument
shape.TextBody!.SetText("Quarterly results");        // keeps the first run's formatting
shape.TextBody.AddParagraph("Second line");

Placeholder inheritance (master, layout, slide) is resolved for you: paragraph.ResolveFormat() returns the effective size, bullet and alignment (docs/presentations.md).

Add, duplicate, move, delete slides

// ShapeCrawler
pres.Slides.Add(layout);               // add from a layout
pres.Slides[0].Remove();

// OneDocument
Slide added = deck.AddSlide("Title and Content");     // by layout name; or AddSlide(layout)
added.SetPlaceholderText("title", "Results");
Slide copy = deck.DuplicateSlide(deck.Slides[0]);
deck.MoveSlide(copy, 0);
deck.DeleteSlide(deck.Slides[2]);

Relationships, content types, notes, sections and custom shows stay consistent. Speaker notes: slide.SetNotesText("...").

Tables

// OneDocument: an existing table shape
foreach (Shape shape in slide.Shapes)
{
    if (shape.Table is { } table) { /* rows, cells, merged cells */ }
}

Tables are read and edited, and slide.AddTable(rows, left, top, width) creates one (positions and sizes are in points).

Pictures

// OneDocument
Shape logo = slide.AddPicture(File.ReadAllBytes("logo.png"), left: 560, top: 20, width: 72, altText: "Company logo");

Templates and output

Fill a deck from data, one slide per item, with the same engine as for documents and workbooks:

Template.Render(path, report, outPath);              // outPath may be .pptx or .pdf

Slides render to PDF and PNG (deck.SaveAs("deck.pdf"), Office.Convert), with the Rendering package. ShapeCrawler does not render.

Not supported or different

• A slide gets pictures and tables through AddPicture and AddTable; there is no high-level call to add other shapes, charts or connectors. Existing ones are kept byte-identical and drawn; other new content comes from templates ({% image %}) or the typed views and markup.
• No animation or transition API: they are preserved and never touched, not rendered.
• No fluent shape-geometry setters (shape.X = ...): geometry is in the shape's typed view.
• .ppt can be read and converted, not written.