StringEditor(3I)

NAME

   StringEditor - single line interactive string editor

SYNOPSIS

   #include <InterViews/streditor.h>

DESCRIPTION

   StringEditor  is  an  interactor that provides a convenient mouse-based
   interactive editor for text strings.  It is suitable for  incorporation
   into  other  components  such  as  dialog  boxes.   Clicking inside the
   StringEditor  (or  calling  the  Edit  function)  initiates  an   edit.
   Subsequent  keyboard events, which need not be inside the StringEditor,
   are interpreted as editing operations on the  text.   Clicking  outside
   the  StringEdit  terminates  the  edit.  StringEditor works with either
   fixed width or proportionally spaced fonts.

EDITING MODEL

   Text is selected with the mouse or with the keyboard.  A  single  click
   of  the  left  mouse  button  selects  a  new  insertion  point between
   characters.  Dragging across the text selects a range of characters.  A
   set  of control characters is mapped into common editing operations.  A
   character not specifically associated  with  commands  is  inserted  in
   place  of the the current selection, the replaced text is lost, and the
   selection becomes an insertion point following the inserted  character.
   Commands currently defined include the following.

   CharacterLeft (^B)
   CharacterRight (^F)
   BeginningOfText (^A)
   EndOfText (^E)
          Move  the selection one character position to the left or right,
          or to the beginning or end of the text.

   Erase (^H, DEL)
   Delete (^D)
          Delete the text of the current selection.  If the  selection  is
          an insertion point, delete the previous character (Erase) or the
          next character (Delete) instead.

   SelectAll (^U)
   SelectWord (^W)
          Select the entire text, or extend the selection to the  left  by
          one whole word.  These commands enable common editing operations
          to be performed  without  using  the  mouse.   For  example,  to
          replace  the previous word in the text, do a SelectWord and type
          the new text.

SCROLLING

   Strings that are too long to fit into the StringEditor can be  scrolled
   horizontally.    Middle-clicking  inside  the  StringBrowser  initiates
   ``grab-scrolling''.  While the button is held  down,  the  StringEditor
   scrolls  the  text  to  follow  the mouse position, making it appear as
   though the user is dragging the test.  Right-clicking  engages  ``rate-
   scrolling,''   a   joy-stick-like  scrolling  interface  in  which  the
   scrolling rate increases as the user drags  the  mouse  away  from  the
   initial  click point.  For example, dragging the mouse rightwards after
   the initial click scrolls the browser rightwards at an increasing rate;
   dragging  leftwards  thereafter  reduces the rate until scrolling stops
   entirely at the initial click point.  Dragging left beyond  this  point
   makes the browser scroll in the reverse direction.

PUBLIC OPERATIONS

   StringEditor(ButtonState*, const char* sample, const char* done)
          Create  a new StringEditor object.  The ButtonState will be used
          to communicate the result of editing operations.  An edit of the
          string will be terminated if any character in the string done is
          typed, and the  ButtonState  will  be  set  to  the  terminating
          character.   The  shape of the new object is calculated from the
          length of the sample string.

   void Message(const char* text)
          Set the contents of the edit buffer to text.

   void Select(int point)
   void Select(int left, int right)
          Select an insertion point or a subrange of the edit buffer.

   void Edit()
   void Edit(const char* text, int left, int right)
          Initiate an edit.  Specifying a string and  selection  range  is
          short  hand  for  first  calling  Message  and  Select  with the
          corresponding parameters.

   const char* Text()
          Return the current value of the edit  buffer.   Note  that  this
          buffer  is  owned by the StringEditor, and that its contents are
          subject to change.  It is the caller's  responsibility  to  copy
          the string if the value will be needed in the long term.

   Handle(Event&)
          Handle  the  event, and read and process subsequent events until
          an Accept or Cancel command is executed or a down  click  occurs
          outside the StringEditor's bounds.

PROTECTED OPERATIONS

   virtual boolean HandleChar(char)
   void InsertText(const char* text, int length)
          Subclasses  of StringEditor can perform additional processing on
          the edit buffer.  For instance, an editor for file  names  might
          do  file  name  completion, or an editor for numeric input might
          check the validity of the string  as  it  is  entered.   Derived
          classes  should  redefine  the  virtual  function  HandleChar as
          required.  HandleChar should return true to  indicate  that  the
          edit  is  completed, or false otherwise.  InsertText can be used
          to insert text into the edit  buffer,  replacing  any  currently
          selected text.

SEE ALSO

   Interactor(3I), Button(3I)

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