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RedHat 9 (Linux i386) - man page for scrollbar (redhat section n)

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

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NAME
       scrollbar - Create and manipulate scrollbar widgets

SYNOPSIS
       scrollbar pathName ?options?

STANDARD OPTIONS
       -activebackground     -highlightcolor	  -repeatdelay
       -background	     -highlightthickness  -repeatinterval
       -borderwidth	     -jump		  -takefocus
       -cursor		     -orient		  -troughcolor
       -highlightbackground  -relief

       See the options manual entry for details on the standard options.

WIDGET-SPECIFIC OPTIONS
       [-activerelief activeRelief]  Specifies the relief to use when displaying the element that
       is active, if any.  Elements other than the active element are  always  displayed  with	a
       raised  relief.	 [-command command]  Specifies	the  prefix of a Tcl command to invoke to
       change the view in the widget associated with the scrollbar.  When a user requests a  view
       change  by  manipulating the scrollbar, a Tcl command is invoked.  The actual command con-
       sists of this option followed by additional information as described later.   This  option
       almost always has a value such as .t xview or .t yview, consisting of the name of a widget
       and either xview (if the scrollbar is for horizontal scrolling)	or  yview  (for  vertical
       scrolling).   All  scrollable  widgets have xview and yview commands that take exactly the
       additional arguments appended by the scrollbar as described in SCROLLING  COMMANDS  below.
       [-elementborderwidth elementBorderWidth]  Specifies  the width of borders drawn around the
       internal elements of the scrollbar (the two arrows and the slider).  The  value	may  have
       any  of	the forms acceptable to Tk_GetPixels.  If this value is less than zero, the value
       of the borderWidth option is used in its place.	[-width width] Specifies the desired nar-
       row  dimension  of  the	scrollbar window, not including 3-D border, if any.  For vertical
       scrollbars this will be the width and for horizontal scrollbars this will be  the  height.
       The value may have any of the forms acceptable to Tk_GetPixels.
_________________________________________________________________

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

       A scrollbar is a widget that displays two arrows, one at each end of the scrollbar, and	a
       slider in the middle portion of the scrollbar.  It provides information about what is vis-
       ible in an associated window that displays an document of some sort (such as a file  being
       edited  or  a drawing).	The position and size of the slider indicate which portion of the
       document is visible in the associated window.  For example, if the slider  in  a  vertical
       scrollbar covers the top third of the area between the two arrows, it means that the asso-
       ciated window displays the top third of its document.

       Scrollbars can be used to adjust the view in the associated window by clicking or dragging
       with the mouse.	See the BINDINGS section below for details.

ELEMENTS
       A  scrollbar  displays five elements, which are referred to in the widget commands for the
       scrollbar:

       arrow1	 The top or left arrow in the scrollbar.

       trough1	 The region between the slider and arrow1.

       slider	 The rectangle that indicates what is visible in the associated widget.

       trough2	 The region between the slider and arrow2.

       arrow2	 The bottom or right arrow in the scrollbar.

WIDGET COMMAND
       The scrollbar 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 scrollbar widgets:

       pathName activate ?element?
	      Marks the element indicated by element as active, which causes it to  be	displayed
	      as  specified  by  the activeBackground and activeRelief options.  The only element
	      values understood by this command are arrow1, slider,  or  arrow2.   If  any  other
	      value  is specified then no element of the scrollbar will be active.  If element is
	      not specified, the command returns the  name  of	the  element  that  is	currently
	      active, or an empty string if no element is active.

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

       pathName configure ?option? ?value option value ...?
	      Query or modify the configuration options of the widget.	If no  option  is  speci-
	      fied,  returns  a  list  describing  all of the available options for pathName (see
	      Tk_ConfigureInfo for information on the format of this list).  If option is  speci-
	      fied with no value, then the command returns a list describing the one named option
	      (this list will be identical to the corresponding sublist of the value returned  if
	      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  this
	      case  the  command  returns  an  empty  string.	Option may have any of the values
	      accepted by the scrollbar command.

       pathName delta deltaX deltaY
	      Returns a real number indicating the fractional change  in  the  scrollbar  setting
	      that corresponds to a given change in slider position.  For example, if the scroll-
	      bar is horizontal, the result indicates how much the scrollbar setting must  change
	      to move the slider deltaX pixels to the right (deltaY is ignored in this case).  If
	      the scrollbar is vertical, the result indicates how much the scrollbar setting must
	      change  to move the slider deltaY pixels down.  The arguments and the result may be
	      zero or negative.

       pathName fraction x y
	      Returns a real number between 0 and 1 indicating where the point given by x  and	y
	      lies  in	the  trough area of the scrollbar.  The value 0 corresponds to the top or
	      left of the trough, the value 1 corresponds to the bottom or right, 0.5 corresponds
	      to  the  middle,	and  so  on.   X  and y must be pixel coordinates relative to the
	      scrollbar widget.  If x and y refer to a point  outside  the  trough,  the  closest
	      point in the trough is used.

       pathName get
	      Returns  the  scrollbar settings in the form of a list whose elements are the argu-
	      ments to the most recent set widget command.

       pathName identify x y
	      Returns the name of the element under the point given by x and y (such as  arrow1),
	      or  an  empty  string if the point does not lie in any element of the scrollbar.	X
	      and y must be pixel coordinates relative to the scrollbar widget.

       pathName set first last
	      This command is invoked by the scrollbar's associated widget to tell the	scrollbar
	      about  the  current  view  in the widget.  The command takes two arguments, each of
	      which is a real fraction between 0 and 1.  The fractions describe the range of  the
	      document	that  is  visible in the associated widget.  For example, if first is 0.2
	      and last is 0.4, it means that the first part of the document visible in the window
	      is 20% of the way through the document, and the last visible part is 40% of the way
	      through.

SCROLLING COMMANDS
       When the user interacts with the scrollbar,  for  example  by  dragging	the  slider,  the
       scrollbar  notifies  the  associated  widget  that it must change its view.  The scrollbar
       makes the notification by evaluating a Tcl command generated from the scrollbar's -command
       option.	 The  command  may  take any of the following forms.  In each case, prefix is the
       contents of the -command option, which usually has a form like .t yview

       prefix moveto fraction
	      Fraction is a real number between 0 and 1.  The widget should adjust  its  view  so
	      that  the point given by fraction appears at the beginning of the widget.  If frac-
	      tion is 0 it refers to the beginning of the document.  1.0 refers to the end of the
	      document, 0.333 refers to a point one-third of the way through the document, and so
	      on.

       prefix scroll number units
	      The widget should adjust its view by number units.  The units are defined in  what-
	      ever  way makes sense for the widget, such as characters or lines in a text widget.
	      Number is either 1, which means one unit should scroll off the top or left  of  the
	      window,  or  -1, which means that one unit should scroll off the bottom or right of
	      the window.

       prefix scroll number pages
	      The widget should adjust its view by number pages.  It  is  up  to  the  widget  to
	      define  the meaning of a page;  typically it is slightly less than what fits in the
	      window, so that there is a slight overlap between the old and new views.	Number is
	      either  1, which means the next page should become visible, or -1, which means that
	      the previous page should become visible.

OLD COMMAND SYNTAX
       In versions of Tk before 4.0, the set and get widget commands used a different form.  This
       form is still supported for backward compatibility, but it is deprecated.  In the old com-
       mand syntax, the set widget command has the following form:

       pathName set totalUnits windowUnits firstUnit lastUnit
	      In this form the arguments are all integers.  TotalUnits gives the  total  size  of
	      the  object  being  displayed  in  the  associated widget.  The meaning of one unit
	      depends on the associated widget;  for example, in a text editor widget units might
	      correspond  to lines of text.  WindowUnits indicates the total number of units that
	      can fit in the associated window at one time.   FirstUnit  and  lastUnit	give  the
	      indices  of  the	first  and  last units currently visible in the associated window
	      (zero corresponds to the first unit of the object).

       Under the old syntax the get widget command returns a list of four integers, consisting of
       the  totalUnits, windowUnits, firstUnit, and lastUnit values from the last set widget com-
       mand.

       The commands generated by scrollbars also have a different form when  the  old  syntax  is
       being used:

       prefix unit
	      Unit  is	an  integer  that  indicates what should appear at the top or left of the
	      associated widget's window.  It has the same meaning as the firstUnit and  lastUnit
	      arguments to the set widget command.

       The most recent set widget command determines whether or not to use the old syntax.  If it
       is given two real arguments then the new syntax will be used in the future, and if  it  is
       given four integer arguments then the old syntax will be used.

BINDINGS
       Tk  automatically  creates  class  bindings  for  scrollbars  that give them the following
       default behavior.  If the behavior is different for vertical  and  horizontal  scrollbars,
       the horizontal behavior is described in parentheses.

       [1]    Pressing	button 1 over arrow1 causes the view in the associated widget to shift up
	      (left) by one unit so that the document appears to move down (right) one unit.   If
	      the button is held down, the action auto-repeats.

       [2]    Pressing button 1 over trough1 causes the view in the associated widget to shift up
	      (left) by one screenful so that the document  appears  to  move  down  (right)  one
	      screenful.  If the button is held down, the action auto-repeats.

       [3]    Pressing	button	1  over  the slider and dragging causes the view to drag with the
	      slider.  If the jump option is true, then the view  doesn't  drag  along	with  the
	      slider;  it changes only when the mouse button is released.

       [4]    Pressing	button	1  over trough2 causes the view in the associated widget to shift
	      down (right) by one screenful so that the document appears to move  up  (left)  one
	      screenful.  If the button is held down, the action auto-repeats.

       [5]    Pressing	button	1  over  arrow2 causes the view in the associated widget to shift
	      down (right) by one unit so that the document appears to move up (left)  one  unit.
	      If the button is held down, the action auto-repeats.

       [6]    If  button  2  is pressed over the trough or the slider, it sets the view to corre-
	      spond to the mouse position;  dragging the mouse with button 2 down causes the view
	      to  drag	with the mouse.  If button 2 is pressed over one of the arrows, it causes
	      the same behavior as pressing button 1.

       [7]    If button 1 is pressed with the Control key down, then if the mouse is over  arrow1
	      or  trough1  the view changes to the very top (left) of the document;  if the mouse
	      is over arrow2 or trough2 the view changes to the very bottom (right) of the  docu-
	      ment;  if the mouse is anywhere else then the button press has no effect.

       [8]    In  vertical scrollbars the Up and Down keys have the same behavior as mouse clicks
	      over arrow1 and arrow2, respectively.  In horizontal scrollbars these keys have  no
	      effect.

       [9]    In  vertical scrollbars Control-Up and Control-Down have the same behavior as mouse
	      clicks over trough1 and trough2, respectively.  In horizontal scrollbars these keys
	      have no effect.

       [10]   In  horizontal  scrollbars  the  Up  and	Down keys have the same behavior as mouse
	      clicks over arrow1 and arrow2, respectively.  In	vertical  scrollbars  these  keys
	      have no effect.

       [11]   In  horizontal  scrollbars  Control-Up  and  Control-Down have the same behavior as
	      mouse clicks over trough1 and trough2, respectively.  In vertical scrollbars  these
	      keys have no effect.

       [12]   The  Prior  and  Next  keys have the same behavior as mouse clicks over trough1 and
	      trough2, respectively.

       [13]   The Home key adjusts the view to the top (left edge) of the document.

       [14]   The End key adjusts the view to the bottom (right edge) of the document.

KEYWORDS
       scrollbar, widget

Tk					       4.1				     scrollbar(n)


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