NAME¶
ntextIndent - 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
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
- •
- 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
::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::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?
- •
- 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.
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 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.
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
SEE ALSO¶
bindtags, ntext, re_syntax, regexp, text
KEYWORDS¶
bindtags, re_syntax, regexp, text