ntextIndent(n) ntext Indentation for the Text Widget ntextIndent(n)______________________________________________________________________________NAMEntextIndent - ntext Indentation for the Text Widget
SYNOPSIS
package require Tcl 8.5
package require Tk 8.5
package require ntext ?0.81?
_________________________________________________________________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 auto‐
matically indent display lines (other than the first) to match the ini‐
tial 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
· 0 - selects Ntext behaviour, i.e. display lines are indented to
match the initial whitespace of the first display line of a log‐
ical line.
No other action is required if this option, and the text wid‐
get'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::clas‐
sicWrap 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
::ntext::newWrapRegexp
· 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::wrapIn‐
dent 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 bind‐
ing, 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 for‐
mat 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?
· 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 textWid‐
get.
::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.
Usage
· ::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 bind‐
ings.
· 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 argu‐
ments ?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 argu‐
ments.
· 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]
::ntext::wrapIndent .t $foo end
To switch to -wrap char mode:
::ntext::wrapIndent .t
SEE ALSO
bindtags, ntext, re_syntax, regexp, text
KEYWORDS
bindtags, re_syntax, regexp, text
ntext 0.81 ntextIndent(n)
