TextDisplay(3I) 					    InterViews Reference Manual 					   TextDisplay(3I)

NAME

       TextDisplay - unstructured text display

SYNOPSIS

       #include <InterViews/textdisplay.h>

DESCRIPTION

       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.

PUBLIC OPERATIONS

       TextDisplay()
       ~TextDisplay(boolean autosized = 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.

       void LineHeight(Coord lineheight)
       void TabWidth(Coord tabwidth)
	      Lines of text will be positioned with baselines separated by lineheight.	Tab characters in the text will cause the following  char-
	      acter to be positioned an integral multiple of tabwidth from the beginning of the line.

       void Resize(Coord xmin, Coord ymin, Coord xmax, Coord ymax)
       void Bounds(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.

       void Draw(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.

       void Redraw(Coord left, Coord bottom, Coord right, Coord top)
	      Redraw a specified region of the display.

       void Scroll(int line, Coord x, Coord y)
	      Scroll  the  display  so	that line line is positioned with its upper-left corner at (x, y).  There are no restrictions on the argu-
	      ments: it is possible to scroll the display so that no lines are visible.

       void InsertLinesAfter(int line, int count)
       void InsertLinesBefore(int line, int count)
       void DeleteLinesAfter(int line, int count)
       void DeleteLinesBefore(int line, int count)
	      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.

       void InsertText(int line, int index, const char*, int count)
       void DeleteText(int line, int index, int count)
       void ReplaceText(int line, const char*, int count)
	      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.

       void Style(int line1, int index1, int line2, int index2, int style)
       void AddStyle(int line1, int index1, int line2, int index2, int style)
       void RemoveStyle(int line1, int index1, int line2, int index2, int style)
	      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.

       void CaretStyle(int style)
       void Caret(int line, int index)
	      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.

       int LineNumber(Coord y)
       int LineIndex(int line, Coord x)
	      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  posi-
	      tion x.

       Coord Width()
       Coord Height()
	      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.

       Coord Base(int line)
       Coord Top(int line)
       Coord Left(int line, int index)
       Coord Right(int line, int index)
	      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.

SEE ALSO

       Painter(2I), Canvas(2I)

InterViews							    23 May 1989 						   TextDisplay(3I)