Provided by: tklib_0.5-3_all bug


       ntextIndent - ntext Indentation for the Text Widget


       package require Tcl  8.5

       package require Tk  8.5

       package require ntext  ?0.81?



       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.


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


       ·      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.

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

       Advanced Use


       ·      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.


       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.


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

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

       ::ntext::wrapIndent textWidget

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

       ::ntext::wrapIndent textWidget index1

       ·      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

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


       ·      ::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.

       ·      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.

       ·      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?.

       ·      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.

       ·      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.


       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


       bindtags, ntext, re_syntax, regexp, text


       bindtags, re_syntax, regexp, text