TextEditor - basic unstructured text editing

       A  TextEditor  is  an  interactor  that  provides  an  interactive interface for simple text editing of a
       TextBuffer.  TextEditor uses an editing model based on a single current  selection.   Editing  operations
       operate  on the text in the selection, alter the position or size of the selection, or scroll the display
       to view other parts of the text.  TextEditor interprets a perspective for interactive scrolling  using  a
       scroller.

       TextEditor  does  not provide a default set of keyboard bindings.  You can implement the key bindings you
       desire by subclassing and redefining the Handle operation or by handling keyboard events in  an  entirely
       separate class.

       TextEditor - basic unstructured text editing

TextEditor(introws,intcols,inttabsize,inthighlight)~TextEditor()
              Create  or  destroy  an  instance of TextEditor.  The natural size of a TextEditor is specified by
              rows and columns.  The TextEditor will be tall enough to display rows lines of text in the current
              font, and it will be wide enough to display columns characters.  For proportionally-spaced  fonts,
              the  width  of  the  character  'n' is taken to be representative.  Tab characters in the text are
              expanded to multiples of tabsize character widths.  The current  selection  highlighted  with  the
              text style highlight.

       voidEdit(TextBuffer*,intindex=0)
              Specify  the  text  buffer  to  edit.   A  text  buffer must be specified before the TextEditor is
              displayed.  The optional index parameter specifies the initial selection point.  If necessary, the
              TextEditor is scrolled so that the selection point is visible.

       intDot()intMark()
              The current selection is bounded by two indices into the text buffer.  By convention these indices
              are called dot and mark.  Dot is the position at which text will be inserted  and  deleted.   Mark
              locates  the  end of the selection that moves as the selection is modified.  When the selection is
              empty (an insertion point), dot and mark are equal.

       voidInsertText(constchar*string,intcount)voidDeleteText(intcount)voidDeleteSelection()
              Edit the text buffer at the current selection.  InsertText inserts count  characters  from  string
              after  dot.   The  selection  becomes  an  insertion  point  following  the  newly  inserted text.
              DeleteText deletes count characters at dot.  If count is positive, the  characters  following  dot
              are deleted; if count is negative the characters before dot are deleted.  The selection becomes an
              insertion  point  in  the place of the deleted text.  DeleteSelection deletes the text between dot
              and mark, changing the selection to an insertion point.

       voidBackwardCharacter(intcount)voidForwardCharacter(intcount)voidBackwardLine(intcount)voidForwardLine(intcount)voidBackwardWord(intcount)voidForwardWord(intcount)voidBackwardPage(intcount)voidForwardPage(intcount)
              Move the current selection forward or backward by the specified number  of  the  specified  units.
              The  default  movement  is one unit.  The selection is not moved before the beginning of after the
              end of the text.

       voidBeginningOfLine()voidEndOfLine()voidBeginningOfWord()voidEndOfWord()voidBeginningOfSelection()voidEndOfSelection()voidBeginningOfText()voidEndOfText()
              Move the current selection forwards or backwards to the specified feature of the text.

       voidScrollToSelection(booleanalways=false)voidSetScrollAlignment(Alignment)AlignmentGetScrollAlignment()
              ScrollToSelction scrolls the display so that dot will be visible.  If dot is currently visible and
              always is false, no scrolling takes place; if dot is not visible or always is true, the display is
              scrolled so that dot will be positioned  as  close  as  possible  to  the  position  specified  by
              SetScrollAlignment.   GetScrollAlignment  returns  the  current  scroll  alignment.   The  default
              alignment is Center.

       voidScrollToView(Coordx,Coordy)voidScrollBy(Coorddx,Coorddy)
              ScrollToView scrolls the display so that the text  currently  at  the  position  (x,  y)  will  be
              visible.   If  the  specified  point  is  currently  visible,  no scrolling takes place.  ScrollBy
              specifies an amount by which to scroll the display.  Positive values scroll  the  display  upwards
              and  to  the  right.  In each case, the final position of the display is limited so that some text
              will be visible.

       voidGrabScroll(Event&)voidRateScroll(Event&)
              Initiate grab scrolling or rate scrolling.  Once called, GrabScroll (RateScroll) polls the current
              mouse position as long as the middle (right) button is pressed.  As GrabScroll polls,  it  scrolls
              the  text  to  follow the mouse position, making it appear as though the user is dragging the text
              itself.  Each time RateScroll polls the mouse, it scrolls the text by an amount  corresponding  to
              the  differential between the current and initial mouse positions.  This creates the illusion of a
              joystick interface: the further away the mouse is from  its  initial  position,  the  greater  the
              scrolling  increment  and  the faster the text appears to scroll; scrolling slows down, stops, and
              reverses direction as the user drags the mouse back towards and past the initial position.

       voidSelect(intdot)voidSelect(intdot,intmark)voidSelectMore(intmark)voidSelectAll()
              Modify the current selection in terms of text indices.  With a single parameter, Select moves both
              dot and mark to the specified index.   With  two  parameters,  dot  and  mark  can  be  controlled
              independently.   SelectMore leaves dot unchanged and moves mark.  SelectAll sets dot to the end of
              the text and mark to the beginning.

       intLocate(Coordx,Coordy)
              Return the text index most closely matching the point (x, y).

Interactor(2I), TextBuffer(3I)

InterViews                                         24 May 1989                                    TextEditor(3I)

#include<InterViews/texteditor.h>