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scale(n) - scale, scale - Create and manipulate scale widgets - man n scale

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scale(n)                     Tk Built-In Commands                     scale(n)



NAME
       scale - Create and manipulate scale widgets

SYNOPSIS
       scale  pathName  ?options?   -activebackground   -foreground    -relief
       -background    -highlightbackground     -repeatdelay           -border-
       width   -highlightcolor     -repeatinterval  -cursor   -highlightthick-
       ness -takefocus -font     -orient   -troughcolor

WIDGET-SPECIFIC OPTIONS
       Some interactions with the scale cause its value to change by ``large''
       increments;   this  option  specifies the size of the large increments.
       If specified as 0, the large increments default to 1/10  the  range  of
       the  scale.   Specifies  the prefix of a Tcl command to invoke whenever
       the scale's value is changed via a widget command.  The actual  command
       consists  of this option followed by a space and a real number indicat-
       ing the new value of the scale.  An integer specifying how many signif-
       icant  digits should be retained when converting the value of the scale
       to a string.  If the number is less(1,3) than or equal  to  zero,  then  the
       scale  picks  the  smallest  value  that guarantees that every possible
       slider position prints as a different string.  A real value correspond-
       ing  to  the  left  or  top end of the scale.  A string(3,n) to display as a
       label for the scale.  For vertical scales the label is  displayed  just
       to  the  right  of the top end of the scale.  For horizontal scales the
       label is displayed just above the left end of the scale.  If the option
       is  specified as an empty string(3,n), no label is displayed.  Specifies the
       desired long dimension of the scale in(1,8) screen units(1,7) (i.e.  any  of  the
       forms  acceptable  to  Tk_GetPixels).   For vertical scales this is the
       scale's height;  for horizontal scales it is the scale's width.  A real
       value  specifying  the  resolution  for  the  scale.   If this value is
       greater than zero then the scale's value will always be rounded  to  an
       even  multiple  of  this value, as will tick marks and the endpoints of
       the scale.  If the value is less(1,3) than zero  then  no  rounding  occurs.
       Defaults  to 1 (i.e., the value will be integral).  Specifies a boolean
       value indicating whether or not the current value of the scale is to be
       displayed.   Specfies  the size of the slider, measured in(1,8) screen units(1,7)
       along the slider's long dimension.  The value may be specified  in(1,8)  any
       of  the  forms acceptable to Tk_GetPixels.  Specifies the relief to use
       when drawing the slider, such as raised or sunken.   Specifies  one  of
       three states for the scale:  normal, active, or disabled.  If the scale
       is disabled then the value may not be changed and the scale won't acti-
       vate.   If the scale is active, the slider is displayed using the color
       specified by the  activeBackground  option.   Must  be  a  real  value.
       Determines  the spacing between numerical tick marks displayed below or
       to the left of the slider.  If 0, no  tick  marks  will  be  displayed.
       Specifies  a real value corresponding to the right or bottom end of the
       scale.  This value may be either less(1,3) than or  greater  than  the  from
       option.   Specifies the name of a global variable to link(1,2) to the scale.
       Whenever the value of the variable changes, the scale  will  update(7,n)  to
       reflect  this  value.  Whenever the scale is manipulated interactively,
       the variable will be modified to reflect the scale's new value.  Speci-
       fies  the  desired narrow dimension of the trough in(1,8) screen units(1,7) (i.e.
       any of the forms acceptable to Tk_GetPixels).  For vertical scales this
       is  the  trough's  width;   for  horizontal scales this is the trough's
       height.


DESCRIPTION
       The scale command creates a new window (given by the pathName argument)
       and makes it into a scale widget.  Additional options, described above,
       may be specified on the command line or in(1,8) the option database to  con-
       figure  aspects  of  the  scale  such  as  its colors, orientation, and
       relief.  The scale command returns its pathName argument.  At the  time(1,2,n)
       this  command is invoked, there must not exist a window named(5,8) pathName,
       but pathName's parent must exist.

       A scale is a widget that displays a  rectangular  trough  and  a  small
       slider.   The  trough corresponds to a range of real values (determined
       by the from, to, and resolution  options),  and  the  position  of  the
       slider  selects  a  particular  real value.  The slider's position (and
       hence the scale's value) may be adjusted with the mouse or keyboard  as
       described in(1,8) the BINDINGS section below.  Whenever the scale's value is
       changed, a Tcl command is invoked (using the command option) to  notify
       other  interested widgets of the change.  In addition, the value of the
       scale can be linked to a Tcl variable (using the variable  option),  so
       that changes in(1,8) either are reflected in(1,8) the other.

       Three  annotations may be displayed in(1,8) a scale widget:  a label appear-
       ing at the top right of the widget (top left for horizontal scales),  a
       number  displayed just to the left of the slider (just above the slider
       for horizontal scales), and a collection of numerical tick  marks  just
       to  the left of the current value (just below the trough for horizontal
       scales).  Each of these three annotations may be  enabled  or  disabled
       using the configuration options.


WIDGET COMMAND
       The  scale  command  creates  a new Tcl command whose name is pathName.
       This command may be used to invoke various operations  on  the  widget.
       It  has  the  following  general  form:  pathName  option ?arg arg ...?
       Option and the args determine the exact behavior of the  command.   The
       following commands are possible for scale widgets:

       pathName cget option
              Returns  the  current value of the configuration option given by
              option.  Option may have any of the values accepted by the scale
              command.

       pathName configure ?option? ?value option value ...?
              Query  or modify the configuration options of the widget.  If no
              option is specified, returns a list describing all of the avail-
              able  options for pathName (see Tk_ConfigureInfo for information
              on the format of this list).  If option  is  specified  with  no
              value,  then the command returns a list describing the one named(5,8)
              option (this list will be identical to the corresponding sublist
              of  the  value  returned  if(3,n) no option is specified).  If one or
              more option-value pairs are specified, then the command modifies
              the  given widget option(s) to have the given value(s);  in(1,8) this
              case the command returns an empty string.  Option may  have  any
              of the values accepted by the scale command.

       pathName coords ?value?
              Returns a list whose elements are the x and y coordinates of the
              point along the centerline of the  trough  that  corresponds  to
              value.   If  value  is omitted then the scale's current value is
              used.

       pathName get ?x y?
              If x and y are omitted, returns the current value of the  scale.
              If x and y are specified, they give pixel coordinates within the
              widget;  the command returns the scale  value  corresponding  to
              the  given  pixel.   Only one of x or y is used:  for horizontal
              scales y is ignored, and for vertical scales x is ignored.

       pathName identify x y
              Returns a string(3,n) indicating what part of the  scale  lies  under
              the  coordinates  given  by  x  and y.  A return value of slider
              means that the point is over the slider;  trough1 means that the
              point is over the portion of the slider above  or to the left of
              the slider; and trough2 means that the point is over the portion
              of the slider below or to the right of the slider.  If the point
              isn't over one of these elements, an empty string(3,n) is returned.

       pathName set(7,n,1 builtins) value
              This command is invoked to  change  the  current  value  of  the
              scale,  and hence the position at which the slider is displayed.
              Value gives the new value for the scale.   The  command  has  no
              effect if(3,n) the scale is disabled.


BINDINGS
       Tk  automatically  creates class bindings for scales that give them the
       following default behavior.  Where the behavior is different for verti-
       cal  and  horizontal  scales,  the  horizontal behavior is described in(1,8)
       parentheses.

       [1]    If button 1 is pressed in(1,8) the trough, the scale's value will  be
              incremented or decremented by the value of the resolution option
              so that the slider moves in(1,8) the direction of the cursor.  If the
              button is held down, the action auto-repeats.

       [2]    If  button  1  is  pressed  over  the  slider, the slider can be
              dragged with the mouse.

       [3]    If button 1 is pressed in(1,8) the trough with the Control key  down,
              the  slider  moves  all  the way to the end of its range, in(1,8) the
              direction towards the mouse cursor.

       [4]    If button 2 is pressed, the scale's value is set(7,n,1 builtins)  to  the  mouse
              position.   If  the  mouse  is  dragged  with button 2 down, the
              scale's value changes with the drag.

       [5]    The Up and Left keys move(3x,7,3x curs_move) the slider up (left) by the  value  of
              the resolution option.

       [6]    The  Down  and  Right  keys  move(3x,7,3x curs_move) the slider down (right) by the
              value of the resolution option.

       [7]    Control-Up and Control-Left move(3x,7,3x curs_move) the slider  up  (left)  by  the
              value of the bigIncrement option.

       [8]    Control-Down  and  Control-Right move(3x,7,3x curs_move) the slider down (right) by
              the value of the bigIncrement option.

       [9]    Home moves the slider to the top (left) end of its range.

       [10]   End moves the slider to the bottom (right) end of its range.

       If the scale is disabled using the state option then none of the  above
       bindings have any effect.

       The  behavior  of  scales  can  be changed by defining new bindings for
       individual widgets or by redefining the class bindings.


KEYWORDS
       scale, slider, trough, widget



Tk                                    4.1                             scale(n)

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