In this book, a document is a window intended for common document-based applications, such as the drawing program, spreadsheet program, and word processor of this book. The Document class implements the document described previously and is a direct subclass of the Window class. It supports caret and dirty flag, keyboard status, menus, accelerators, the mouse wheel, scroll bars, and drop files.

Document.h

namespace SmallWindows { 
  extern const Size USLetterPortrait, LineSize; 

The keyboard holds either the insert or overwrite mode.

  enum KeyboardMode {InsertKeyboard, OverwriteKeyboard}; 

Similar to Window, Document has a public constructor intended for instantiation and a protected constructor intended for subclasses. A document of the Document class can accept drop files, and the line size is used by the scroll bar methods:

  class Document : public Window { 
    public: 
      Document(CoordinateSystem system, Size pageSize, 
          ...