ntextIndent(n)       ntext Indentation for the Text Widget      ntextIndent(n)



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NAME
       ntextIndent - ntext Indentation for the Text Widget

SYNOPSIS
       package require Tcl  8.5

       package require Tk  8.5

       package require ntext  ?0.81?

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DESCRIPTION
       The ntext package provides a binding tag named Ntext for use by text
       widgets in place of the default Text binding tag.

       Tk's text widget may be configured to wrap lines of text that are
       longer than the width of the text area, a feature that is familiar from
       text editors and word processors.  A complete line of text (delimited
       by newlines, or by the beginning or end of the document) is called a
       "logical line".  When a logical line is wrapped onto more than one line
       of the display area, these fragments of the logical line are called
       "display lines".

       If a logical line begins with whitespace, then wrapped display lines
       begin further to the left than the first display line, which can make
       the text layout untidy and difficult to read.  The Ntext binding tag
       provides facilities so that a text widget in -wrap word mode will
       automatically indent display lines (other than the first) to match the
       initial whitespace of the first display line.

       This indentation is available to text widgets only in -wrap word mode.

CONFIGURATION OPTIONS
       The behavior of Ntext may be configured application-wide by setting the
       values of a number of namespace variables:

       ::ntext::classicWrap

       o      0 - selects Ntext behaviour, i.e. display lines are indented to
              match the initial whitespace of the first display line of a
              logical line.

              No other action is required if this option, and the text
              widget's -wrap option, are set before any text is entered in the
              widget, and if text is entered and edited only by the mouse and
              keyboard.  If, instead, text is manipulated by the script, or if
              the text widget's -wrap option or the value of
              ::ntext::classicWrap are changed while the widget holds text,
              then calls to ntext functions are needed to alter the
              indentation.  See the section INDENTING DISPLAY LINES for
              detailed instructions.

       o      1 - (default value) selects classic Text behaviour, i.e. no
              indentation.

       Advanced Use

       ::ntext::newWrapRegexp

       o      the value is a regexp pattern that determines the character of a
              logical line to which display lines other than the first will be
              aligned.  The default value, [^[:space:]], ensures alignment
              with the first non-whitespace character.

INDENTING DISPLAY LINES
       To use Ntext 's display line indentation:

       [1]    Set the variable ::ntext::classicWrap to 0 (default value is 1).
              This enables bindings that will preserve indentation whenever
              the user modifies the widget contents using the keyboard and
              mouse.  If the widget already holds text, call
              ::ntext::wrapIndent to initialise indentation.

              Further instructions apply if the program changes the widget's
              contents, wrap configuration, or indent configuration.

       [2]    The program can change the text contents, e.g. by the .text
              insert command.  Such a change does not trigger a window
              binding, so the program should explicitly call function
              ::ntext::wrapIndent after inserting text.

       [3]    Auto-indentation occurs only if the widget is in -wrap word
              mode.  If the program changes to or from -wrap word when the
              widget is not empty, it should call ::ntext::wrapIndent to
              format the widget's text.

       [4]    If indentation is used, and then switched off by setting
              ::ntext::classicWrap to 1,  call ::ntext::wrapIndent to remove
              indentation.

FUNCTIONS
       ::ntext::wrapIndent textWidget ?index1? ?index2?

       o      Adjust the indentation of a text widget.  Different cases are
              discussed below.

       ::ntext::wrapIndent textWidget

       o      Adjust the indentation of all the text in text widget
              textWidget.

       ::ntext::wrapIndent textWidget index1

       o      Adjust the indentation of a single logical line of a text widget
              - the line of textWidget that contains the index index1.

       ::ntext::wrapIndent textWidget index1 index2

       o      Adjust the indentation of a range of logical lines of a text
              widget - the lines of textWidget that contain indices index1 to
              index2.

       Usage

       o      ::ntext::wrapIndent should be called only if the script changes
              the widget's contents or display properties.  If the contents of
              the widget have been modified by the keyboard or mouse, it is
              not necessary for the script to call ::ntext::wrapIndent because
              the appropriate calls are made automatically by the Ntext
              bindings.

       o      The script should normally call ::ntext::wrapIndent if, for
              example, the script changes one of the following when the widget
              is not empty: the value of ::ntext::classicWrap, or the widget's
              -wrap status, or the widget's tab spacing, or the font size, or
              the widget's contents.

       o      A call of the form ::ntext::wrapIndent textWidget will always
              suffice, but if changes are needed only to certain lines, it is
              more efficient to specify those lines with the optional
              arguments ?index1?, ?index2?.

       o      If the widget is in -word wrap mode, and if ::ntext::classicWrap
              is set to 0, ::ntext::wrapIndent will apply indentation to the
              logical lines within the range specified by the function's
              arguments.

       o      In other cases, i.e. if the widget is in -word char or -word
              none mode, or if ::ntext::classicWrap is set to 1,
              ::ntext::wrapIndent will remove the indentation of the logical
              lines within the range specified by the function's arguments.

EXAMPLES
       To switch on Ntext 's indentation and use it in widget .t:


              package require ntext
              set ::ntext::classicWrap 0
              text .t -wrap word
              bindtags .t {.t Ntext . all}

       To decide later to switch off Ntext 's indentation:


              set ::ntext::classicWrap 1
              ::ntext::wrapIndent .t

       To decide later to switch Ntext 's indentation back on:


              set ::ntext::classicWrap 0
              ::ntext::wrapIndent .t 1.0 end

       To inject some text into the widget:


              set foo [.t index end]
              .t insert end {This line was added by the script, not the keyboard!}
              ::ntext::wrapIndent .t $foo end

       To switch to -wrap char mode:


              .t configure -wrap char
              ::ntext::wrapIndent .t


BUGS, IDEAS, FEEDBACK
       This document, and the package it describes, will undoubtedly contain
       bugs and other problems.  Please report such in the category ntext of
       the Tklib Trackers [http://core.tcl.tk/tklib/reportlist].  Please also
       report any ideas for enhancements you may have for either package
       and/or documentation.

SEE ALSO
       bindtags, ntext, re_syntax, regexp, text

KEYWORDS
       bindtags, re_syntax, regexp, text



tklib                                0.81                       ntextIndent(n)
