Public Enum to define highlight mode of text box field.
// Load an existing PDF document
let document: PdfDocument = new PdfDocument(data, password);
// Access text box field
let field: PdfTextBoxField = document.form.fieldAt(0) as PdfTextBoxField;
// Sets the highlight mode of text box field as outline
field.highlightMode = PdfHighlightMode.outline;
// Save the document
document.save('output.pdf');
// Destroy the document
document.destroy();invert - Specifies the type of invert.noHighlighting - Specifies the type of noHighlighting.outline - Specifies the type of outline.push - Specifies the type of push.