ntext - Alternative Bindings for the Text Widget
The purpose of the ntext package is to make the text widget behave more like other text-editing applications. It makes the text widget more useful for implementing a text editor, and makes it behave in a way that will be more familiar to most users.
The package provides a binding tag named Ntext for use by text widgets in place of the default Text binding tag.
Package ntext 's functions and variables are contained entirely in the ::ntext namespace; its other code is contained in the binding tag Ntext. ntext has no exports to the global or other namespaces, and no new widget commands. It uses modified copies of the Tk code, leaving the original code, and the Text binding tag, unchanged.
The differences between the Ntext binding tag and the default Text binding tag are in three categories:
Some Text bindings behave differently from most text-editing applications. Ntext gives these bindings more familiar behaviour. For details see ntextBindings.
When a logical line with leading whitespace is word-wrapped onto more than one display line, the wrapped display lines begin further to the left than the first display line, which can make the text layout untidy and difficult to read. Ntext can indent the wrapped lines to match the leading whitespace of the first display line (this facility is switched off by default). For details see ntextIndent.
When the user navigates or selects text, Tcl/Tk sometimes needs to detect word boundaries. Ntext provides improved rules for word boundary detection. For details see ntextWordBreak.
The remainder of this page describes the basic use and configuration of all three aspects of Ntext. For more detailed information on the different facilities of Ntext, see the pages ntextBindings, ntextIndent, and ntextWordBreak.
See Section EXAMPLE for how to apply the Ntext binding tag in place of the Text binding tag.
Replacement for ::tk_textCopy.
Replacement for ::tk_textCut that also maintains Ntext indentation (see ntextIndent).
Replacement for ::tk_textPaste that also maintains Ntext indentation (see ntextIndent).
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 (see ntextIndent).
Ntext provides alternatives to a number of behaviours of the classic Text binding tag. Where there is an option, the Ntext behaviour (except for display-line indentation) is switched on by default.
The behaviour of Ntext may be configured application-wide by setting the values of a number of namespace variables:
::ntext::classicAnchor
0 - (default value) selects Ntext behaviour, i.e. the anchor point is fixed
1 - selects classic Text behaviour, i.e. the anchor point is variable
For more information see ntextBindings
::ntext::classicExtras
0 - (default value) selects Ntext behaviour, i.e. several traditional Text bindings are de-activated
1 - selects classic Text behaviour, i.e. all Text bindings are activated
For more information see ntextBindings
::ntext::classicMouseSelect
0 - (default value) selects Ntext behaviour, i.e. the anchor point for mouse selection operations is moved by keyboard navigation
1 - selects classic Text behaviour
For more information see ntextBindings
::ntext::classicParagraphs
0 - (default value) on macOS Aqua, certain keyboard bindings are made to behave in the same way as the Mac application TextEdit. The bindings involve vertical scrolling of the screen and are <?Shift-?Option-(Up|Down)>.
1 - on macOS Aqua, certain keyboard bindings are made to behave in the same way as classic Text, ignoring the conventions of Aqua. The bindings involve vertical scrolling of the screen and are <?Shift-?Option-(Up|Down)>.
For more information see ntextBindings
::ntext::classicSelection
0 - (default value on macOS Aqua) selects Mac-like behaviour, i.e. when a navigation keystroke cancels a selection, the insert mark first moves to the end of the selection determined by the navigation direction of the keystroke, and then the keystroke is applied.
1 - (default value except on macOS Aqua) selects PC-like behaviour (the same as classic Text), i.e. when a navigation keystroke cancels a selection, the insert mark is not moved before the keystroke is applied.
For more information see ntextBindings
::ntext::classicWordBreak
0 - (default value) selects Ntext behaviour, i.e. platform-independent, two classes of word characters and one class of non-word characters.
1 - selects classic Text behaviour, i.e. platform-dependent, one class of word characters and one class of non-word characters
After changing this value, the matching patterns should be recalculated. See ntextWordBreak for details and advanced configuration options.
::ntext::classicWrap
0 - selects Ntext behaviour, i.e. display lines of text widgets in -wrap word mode are indented to match the initial whitespace of the first display line of a logical line. If the widget already holds text when this value is set, a function call may be necessary. See ntextIndent for detailed instructions on the use of Ntext 's indentation.
1 - (default value) selects classic Text behaviour, i.e. no indentation
For more information see ntextIndent
::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.
For more information see ntextIndent
::ntext::overwrite
0 - (initial value) text typed at the keyboard is inserted into the widget
1 - text typed at the keyboard overwrites text already in the widget
The value is toggled by the Insert key (except on macOS Aqua where there is no such key).
For more information see ntextBindings
::ntext::useBlockCursor
0 - the block cursor will not be used. When the widget is in overwrite mode (see ::ntext::overwrite), the ordinary cursor will change color instead.
1 - the block cursor will be used when the widget is in overwrite mode (see ::ntext::overwrite).
The default value depends on the version of Tk. In versions of Tk earlier than 8.5.12, the sizing of the block cursor had a bug, and ::ntext::useBlockCursor defaults to 0. From 8.5.12 onwards the bug is fixed, and ::ntext::useBlockCursor defaults to 1.
For more information see ntextBindings
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.
To create a text widget .t and use the Ntext bindings:
package require ntext
text .t
bindtags .t {.t Ntext . all}
See bindtags for more information.