Enable 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 when rendering multi-layered PDF document GroupDocs.Viewer for Java provides setEnableLayeredRendering() 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.
try (Viewer viewer = new Viewer("sample.pdf")) {
HtmlViewOptions viewOptions = HtmlViewOptions.forEmbeddedResources();
viewOptions.getPdfOptions().setEnableLayeredRendering(true);
viewer.view(viewOptions);
}