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ntextBindings(3tk) Alternative Bindings for the Text Widget ntextBindings(3tk) 





NAME


ntextBindings - Alternative Bindings for the Text Widget






SYNOPSIS


package require Tcl 8.5-


package require Tk 8.5-


package require ntext ?1.0?










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 (not the start of the next line). If the widget is in
      -wrap word 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 (not the next
      line, or the region at the end of the line where there are no
      characters). If the widget is in -wrap word 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. (In contrast, the Text binding tag uses Insert as a
      method to paste the "primary selection", a task that can be
      accomplished instead by mouse middle-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 CONFIGURATION OPTIONS).
    • 
  
  • 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 CONFIGURATION
      OPTIONS).
    • 
  
  • Selecting with <Shift-Button1> selects from the previous position of
      the insertion cursor. (In the Text binding tag, the selection anchor
      may be the position of the previous mouse click.)
    • 
  
  • <Shift-Button1> operations do not alter the selection anchor. (In
      the Text binding tag, they do.)
    • 
  
  • 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>.
    • 







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.
    • 







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.






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 Tklib Trackers
    [https://core.tcl-lang.org/tklib/reportlist].






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}









SEE ALSO


bindtags, ntext, ntextIndent, text






KEYWORDS


bindtags, text







  

    1.0
    tklib