fieldAppearance := annotator.FieldAppearance{OnlyIfMissing: true, RegenerateTextFields: true}
// specify a full set of appearance styles
fieldAppearance.SetStyle(annotator.AppearanceStyle{
AutoFontSizeFraction: 0.70,
FillColor: model.NewPdfColorDeviceRGB(1, 1, 1),
BorderColor: model.NewPdfColorDeviceRGB(0, 0, 0),
BorderSize: 2.0,
AllowMK: false,
TextColor: model.NewPdfColorDeviceRGB(0.5, 0.8, 0.8), // text color as normalized RGB values
})
// Populate the form data with appearance.
pdfReader.AcroForm.FillWithAppearance(fieldData, fieldAppearance)