Layered rendering
When rendering into HTML GroupDocs.Viewer renders text and graphics as a single layer that improves performance and reduces HTML document size. To improve content positioning wen rendering multi-layered PDF document GroupDocs.Viewer provides EnableLayeredRendering option that enables rendering of text and graphics according to z-order in original PDF document when rendering into HTML.
This option is supported when rendering to HTML only.
Following code sample demonstrates how to enable layered rendering.
using (Viewer viewer = new Viewer("sample.pdf"))
{
HtmlViewOptions viewOptions = HtmlViewOptions.ForEmbeddedResources();
viewOptions.PdfOptions.EnableLayeredRendering = true;
viewer.View(viewOptions);
}