GcDocs PDF Viewer allows you to render the customized appearance of radio and checkbox buttons. It provides three appearance rendering types which can be configured by using the fieldsAppearance option.

Custom

This is the default appearance type and is close to the styles defined in the PDF document. As can be observed in the below image, it supports background color and border styles as well:

Web

This is the standard form field appearance using platform-native styling. The styles depend on the OS or browser being used. Refer this for more details. The below image shows the 'Web' appearance of radio and checkbox buttons in a PDF document:

var viewer = new GcPdfViewer("#root", { fieldsAppearance: { radioButton: "Web", checkBoxButton: "Web" } });

Predefined

This appearance type renders the radio and checkbox buttons exactly as defined in the PDF. The Predefined appearance streams from the PDF document when available, otherwise the custom appearance is used. The below image shows the 'Predefined' appearance of radio and checkbox buttons in a PDF document:

var viewer = new GcPdfViewer("#root", { fieldsAppearance: { radioButton: "Predefined", checkBoxButton: "Predefined" } });