ntextBindings - Alternative Bindings for the Text Widget

Bugs

       This  version  of  ntext is intended to be compatible with all releases of Tk 8.5, 8.6, and 8.7, 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   TklibTrackers    [https://core.tcl-
       lang.org/tklib/reportlist].

Configuration Options

Ntext provides alternatives to a number of behaviours of the classic Text binding tag. Where there is an
option, the Ntext behaviour is switched on by default, except for display-line indentation which is
discussed on a separate page at ntextIndent.

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

::ntext::classicExtras

• 0 - (default value) selects Ntext behaviour, i.e. several "extra" Text bindings are de-activated

• 1 - selects classic Text behaviour, i.e. the "extra" Text bindings are activated

::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

::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 for the Windows
and X11 windowing systems and the classic Text, ignoring the conventions of Aqua. The bindings
involve vertical scrolling of the screen and are <?Shift-?Option-(Up|Down)>.

::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.

::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.

::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.

Description

       The ntext package provides a binding tag named Ntext for use by text widgets in place of the default Text
       binding tag.

       The  Text  binding  tag  provides  around  one  hundred  bindings to the text widget (the exact number is
       platform-dependent).  A few of these behave in a way that  is  different  from  most  contemporary  text-
       editing applications.  Ntext aims to provide more familiar behaviour.

       Features of the Ntext bindings that differ from the default Text bindings:

       •      Clicking  near the end of a (logical) line moves the cursor to the end of that line (notthestartofthenextline).  If the widget is in -wrapword mode, the same rule applies to display lines.

       •      Double-clicking or dragging near the end of a (logical) line will highlight/select characters from
              the end of that line (notthenextline,ortheregionattheendofthelinewheretherearenocharacters).  If the widget is in -wrapword mode, the same rule applies to display lines.

       •      On  windowing  systems  other  than  macOS  Aqua, the Home key implements "Smart Home" (successive
              keypresses move the cursor to the start of the display line,  then  to  the  first  non-whitespace
              character  at the start of the logical line, then toggles between the beginning and end of leading
              whitespace); the End key implements "Smart End" (which is similar  to  "Smart  Home").   On  macOS
              Aqua, this functionality is provided by the operations <Command-Left> and <Command-Right>.

       •      When  a selection exists, a "Paste" operation (e.g. <Control-v>) overwrites the selection (as most
              editors do), and does so on all platforms.

       •      On windowing systems  other  than  macOS  Aqua,  the  Insert  key  toggles  between  "Insert"  and
              "Overwrite"  modes for keyboard input.  (Incontrast,theTextbindingtaguses Insert asamethodtopastethe"primaryselection",ataskthatcanbeaccomplishedinsteadbymousemiddle-click.)

       •      The Escape key clears the selection.

       •      On the macOS Aqua windowing system,  Ntext  follows  Aqua  conventions  for  keyboard  navigation.
              Certain  bindings related to vertical scrolling can be forced to behave in the same way as for the
              Windows and X11 windowing  systems,  by  setting  ::ntext::classicParagraphs  to  1  (see  Section
              CONFIGURATIONOPTIONS).

       •      On  the  macOS  Aqua  windowing system, Ntext follows Aqua conventions for placement of the insert
              mark when keyboard navigation cancels a selection.  This behavior can be switched off  by  setting
              ::ntext::classicSelection to 1 (see Section CONFIGURATIONOPTIONS).

       •      Selecting with <Shift-Button1> selects from the previous position of the insertion cursor. (IntheTextbindingtag,theselectionanchormaybethepositionofthepreviousmouseclick.)

       •      <Shift-Button1> operations do not alter the selection anchor. (IntheTextbindingtag,theydo.)

       •      By default, the Ntext binding tag does not provide several of the Control-key bindings supplied by
              the  Text  binding  tag.  Modern keyboards offer alternatives, such as cursor keys for navigation;
              modern applications often use the Control-key bindings for other purposes  (e.g.  <Control-p>  for
              "print").

       In the last three cases, the behavior of Text is often useful, so Ntext gives you the option of retaining
       it,  by setting variables defined in the ::ntext namespace to 1 (instead of their default 0).  Explaining
       these features in more detail:

       •      If the mouse is clicked at position A, then the keyboard is used to move the  cursor  to  B,  then
              shift  is  held down, and the mouse is clicked at C: the Text binding tag gives a selection from A
              to C; the Ntext gives a selection from B to C.  If you want Ntext to  behave  like  Text  in  this
              respect, set ::ntext::classicMouseSelect to 1.

       •      The  Text  binding  tag  allows  successive  <Shift-Button-1>  events  to  change both ends of the
              selection, by moving the selection anchor to the end of the  selection  furthest  from  the  mouse
              click.   Instead,  the  Ntext binding tag fixes the anchor, and multiple Shift-Button-1 events can
              only move the non-anchored end of the selection.  If you want Ntext to behave like  Text  in  this
              respect,  set  ::ntext::classicAnchor  to 1.  In both Text and Ntext, keyboard navigation with the
              Shift key held down alters the selection and keeps the selection anchor fixed.

       •      The following "extra" Text bindings are switched off by default, but can be activated in Ntext  by
              setting ::ntext::classicExtras to 1: <Control-a>, <Control-b>, <Control-d>, <Control-e>, <Control-
              f>,  <Control-h>,  <Control-i>,  <Control-k>,  <Control-n>, <Control-o>, <Control-p>, <Control-t>,
              <Control-space>, <Control-Shift-space>.

Example

       To use Ntext but keep classic Text 's variable-anchor feature:

              package require ntext
              text .t
              set ::ntext::classicAnchor 1
              bindtags .t {.t Ntext . all}

Internals

       In order to remain independent of the version of Tk (8.5 or 8.6), ntext defines its own  virtual  events.
       These  new virtual events are used only in the Ntext binding tag, and therefore do not interfere with the
       real or virtual events used in other code.

       These events include <<NtextCut>>, <<NtextCopy>>, <<NtextPaste>> which are  used  in  place  of  <<Cut>>,
       <<Copy>>, <<Paste>> respectively.

       The definition of the virtual event <<NtextCut>> (etc) is similar to that of <<Cut>> (etc) in Tk 8.6.

Keywords

       bindtags, text

tklib                                                  1.0                                    ntextBindings(3tk)

Name

       ntextBindings - Alternative Bindings for the Text Widget

Synopsis


       package require Tcl8.5-

       package require Tk8.5-
       package require ntext?1.0?

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