TextDisplay - unstructured text display

       A  TextDisplay  manages  and  displays  an array of lines of text.  Operations are provided to insert and
       delete lines, to insert and delete text within a line, and  to  scroll  the  display.   TextDisplays  are
       typically used to implement interactors that require non-trivial display of unstructured text.

       The  array  is addressed by a line number and an index into the line.  Text can be inserted or deleted at
       arbitrary positions.  By default, the first character in line number zero is positioned with its top left
       corner at the top left corner of  the  TextDisplay.   The  display  is  automatically  updated  following
       modifications  to  the text or when scrolling.  Each character in the array has an associated text style.
       Operations are provided to apply, add, or remove font styles to a range of the text.  TextDisplay can  be
       used   with   both   constant-width   and   proportionally-spaced  fonts  and  with  arbitrary  geometric
       transformations.

       TextDisplay - unstructured text display

TextDisplay()~TextDisplay(booleanautosized=false)
              Create or destroy a TextDisplay.  If autosized is true, the TextDisplay  will  automatically  grow
              its size as text is added.  The default is to keep the size constant.

       voidLineHeight(Coordlineheight)voidTabWidth(Coordtabwidth)
              Lines  of  text  will be positioned with baselines separated by lineheight.  Tab characters in the
              text will cause the following character to be positioned an integral multiple of tabwidth from the
              beginning of the line.

       voidResize(Coordxmin,Coordymin,Coordxmax,Coordymax)voidBounds(Coord&xmin,Coord&ymin,Coord&xmax,Coord&ymax)
              Specify or query the size of the display.  Only lines of text  that  fall  completely  inside  the
              specified  region  will be displayed.  TextDisplay will not draw on any part of the canvas outside
              the specified bounds.  Conversely, TextDisplay is free to draw on any part of  the  canvas  within
              the specified bounds.

       voidDraw(Painter*,Canvas*)
              Specify  the  painter  and  canvas  to use for drawing operations; the painter specifies the font,
              colors, and geometric transformation.  Draw should be called before performing  any  operation  on
              the  TextDisplay  which  produces  output  or  requires  graphical information, or when there is a
              possibility that the painter or canvas has changed since the function was last called.

       voidRedraw(Coordleft,Coordbottom,Coordright,Coordtop)
              Redraw a specified region of the display.

       voidScroll(intline,Coordx,Coordy)
              Scroll the display so that line line is positioned with its upper-left corner at  (x,  y).   There
              are  no  restrictions  on the arguments: it is possible to scroll the display so that no lines are
              visible.

       voidInsertLinesAfter(intline,intcount)voidInsertLinesBefore(intline,intcount)voidDeleteLinesAfter(intline,intcount)voidDeleteLinesBefore(intline,intcount)
              Insert or delete whole lines of text.  Line line is not affected by the  operation.   Other  lines
              will  move  up or down to accommodate the changes.  Newly inserted lines are blank.  The specified
              line need not refer to an existing line.

       voidInsertText(intline,intindex,constchar*,intcount)voidDeleteText(intline,intindex,intcount)voidReplaceText(intline,constchar*,intcount)
              Modify the text within line line.  InsertText and DeleteText will cause the  following  characters
              on the line to move to accommodate the changes.  ReplaceText replaces the entire text of the line.
              If the specified line is non-existent, a new line will be created.

       voidStyle(intline1,intindex1,intline2,intindex2,intstyle)voidAddStyle(intline1,intindex1,intline2,intindex2,intstyle)voidRemoveStyle(intline1,intindex1,intline2,intindex2,intstyle)
              Modify  the  styling  of  a  range of text. Style replaces any existing style; AddStyle adds style
              style in addition to any existing styles; RemoveStyle removes style style without affecting  other
              existing  styles.   Styles  are  specified  as  any  combination of the constants Plain, Boldface,
              Underlined, and Reversed.

       voidCaretStyle(intstyle)voidCaret(intline,intindex)
              Control the shape and position of a caret.  Valid caret styles are  currently  NoCaret,  BarCaret,
              UnderscoreCaret  and  OutlineCaret.  TextDisplay does not automatically adjust the position of the
              caret following insertions and deletions.

       intLineNumber(Coordy)intLineIndex(intline,Coordx)
              Map x and y display coordinates into line and index  text  coordinates.   LineNumber  returns  the
              number  of  the line that contains the specified vertical position y.  LineIndex returns the index
              into line line that best corresponds to the specified horizontal position x.

       CoordWidth()CoordHeight()
              Return the width or the height of the text currently displayed by the TextDisplay.  Width  returns
              the  width  of  the  longest line in the display.  Height returns the distance from the top of the
              topmost line to the bottom of the bottommost line.  Note that these dimensions do not  necessarily
              correspond to the TextDisplay's bounds as returned by Bounds.

       CoordBase(intline)CoordTop(intline)CoordLeft(intline,intindex)CoordRight(intline,intindex)
              Map  line and index text coordinates into x and y display coordinates.  The return values define a
              bounding box for the character specified by line and index.

Painter(2I), Canvas(2I)

InterViews                                         23 May 1989                                   TextDisplay(3I)

#include<InterViews/textdisplay.h>