Custom widgets

When the standard widgets do not do what you need, you can make your own. There are two ways:

• Build a widget from scratch: a struct that embeds widget.BaseWidget, and a renderer that draws it with canvas primitives. You control every pixel and every event.
• Extend a widget: embed an existing widget, such as widget.Entry, and add or replace methods. You keep everything the widget already does.

Before writing a widget, check whether a container of existing widgets does the job. A widget is worth it when you need a new look, new input handling, or a reusable unit with its own state and API.