ntextIndent - ntext Indentation for the Text Widget
package require Tcl 8.5
package require Tk 8.5
package require ntext ?1.0?
::ntext::new_textCopy pathName
::ntext::new_textCut pathName
::ntext::new_textPaste pathName
::ntext::syncIndentColor pathName
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.
- ::ntext::new_textCopy pathName
- Replacement for ::tk_textCopy.
- ::ntext::new_textCut pathName
- Replacement for ::tk_textCut that also maintains Ntext
indentation.
- ::ntext::new_textPaste pathName
- Replacement for ::tk_textPaste that also maintains Ntext
indentation.
- ::ntext::syncIndentColor pathName
- Command to apply the current value of the variable
::ntext::indentColor to existing lines in a text widget. This
command is useful if a text widget has been created, text has been
inserted in the widget, and then the value of
::ntext::indentColor is changed.
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.
::ntext::indentColor
- {} - if the value is the empty string, then the indent of wrapped
display lines has the same color as the widget background.
- color - a valid Tk color to use for the indent of wrapped display
lines (default value #d9d9d9).
Coloring is implemented with the text widget tag option
-lmargincolor, which is available from Tk 8.6.6 onwards.
Ntext indent coloring has no effect in earlier versions of
Tk.
The value of ::ntext::indentColor will often be set at
startup. If the value is changed when text widgets already exist and
contain text, those widgets can be updated by calling command
::ntext::syncIndentColor.
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.
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.
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.
This version of ntext is intended to be compatible with all
releases of Tk 8.5 and 8.6, and with the branches
core-8-5-branch, core-8-6-branch, and trunk in the
source code repository for Tk. Any incompatibility with any of these
versions, for any Tk windowing system, should be reported as a bug.
Please report such in the category ntext of the Tklib Trackers
[http://core.tcl.tk/tklib/reportlist].
To switch on Ntext 's indentation and use it in widget .t,
using the default indent color #d9d9d9:
package require ntext
set ::ntext::classicWrap 0
text .t -wrap word
bindtags .t {.t Ntext . all}
To switch on Ntext 's indentation and use it in widget .t, without
colored indents:
package require ntext
set ::ntext::classicWrap 0
set ::ntext::indentColor {}
text .t -wrap word
bindtags .t {.t Ntext . all}
To switch on Ntext 's indentation and use it in widget .t, coloring the
indents black:
package require ntext
set ::ntext::classicWrap 0
set ::ntext::indentColor black
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 change the indentation color when a widget .t already holds text:
set ::ntext::indentColor black
::ntext::syncIndentColor .t
To switch to -wrap char mode:
.t configure -wrap char
::ntext::wrapIndent .t
bindtags, ntext, re_syntax, regexp, text
bindtags, re_syntax, regexp, text