NAME
       canvas - Create and manipulate canvas widgets

SYNOPSIS
       canvas pathName ?options?

STANDARD OPTIONS
       -background     -highlightthickness            -insertwidth-takefocus
       -borderwidth    -insertbackground              -relief-xscrollcommand
       -cursor         -insertborderwidth             -selectbackground-yscrollcommand
       -highlightbackground           -insertofftime  -selectborderwidth
       -highlightcolor -insertontime  -selectforeground

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

WIDGET-SPECIFIC OPTIONS
       Command-Line Name:-closeenough
       Database Name:  closeEnough
       Database Class: CloseEnough

              Specifies a  floating-point  value  indicating  how
              close the mouse cursor must be to an item before it
              is considered to be ``inside'' the item.   Defaults
              to 1.0.

       Command-Line Name:-confine
       Database Name:  confine
       Database Class: Confine

              Specifies a boolean value that indicates whether or
              not it should be allowable to set the canvas's view
              outside  the  region  defined  by  the scrollRegion
              argument.  Defaults to true, which means  that  the
              view  will be constrained within the scroll region.

       Command-Line Name:-height
       Database Name:  height
       Database Class: Height

              Specifies a desired window height that  the  canvas
              widget  should  request  from its geometry manager.
              The value may be specified  in  any  of  the  forms
              described in the COORDINATES section below.

       Command-Line Name:-scrollregion
       Database Name:  scrollRegion
       Database Class: ScrollRegion

              Specifies  a  list with four coordinates describing
              the left, top, right, and bottom coordinates  of  a
              rectangular   region.   This  region  is  used  for
              scrolling purposes and  is  considered  to  be  the
              boundary of the information in the canvas.  Each of
              the coordinates may be  specified  in  any  of  the
              forms given in the COORDINATES section below.

       Command-Line Name:-width
       Database Name:  width
       Database Class: width

              Specifies  a  desired  window width that the canvas
              widget should request from  its  geometry  manager.
              The  value  may  be  specified  in any of the forms
              described in the COORDINATES section below.

       Command-Line Name:-xscrollincrement
       Database Name:  xScrollIncrement
       Database Class: ScrollIncrement

              Specifies an increment for horizontal scrolling, in
              any  of  the  usual forms permitted for screen dis-
              tances.  If the value of  this  option  is  greater
              than  zero,  the horizontal view in the window will
              be constrained so that the canvas x  coordinate  at
              the  left edge of the window is always an even mul-
              tiple of xScrollIncrement;  furthermore, the  units
              for  scrolling  (e.g.,  the change in view when the
              left and right arrows of a scrollbar are  selected)
              will  also  be  xScrollIncrement.   If the value of
              this option is less than or  equal  to  zero,  then
              horizontal scrolling is unconstrained.

       Command-Line Name:-yscrollincrement
       Database Name:  yScrollIncrement
       Database Class: ScrollIncrement

              Specifies  an  increment for vertical scrolling, in
              any of the usual forms permitted  for  screen  dis-
              tances.   If  the  value  of this option is greater
              than zero, the vertical view in the window will  be
              constrained  so that the canvas y coordinate at the
              top edge of the window is always an  even  multiple
              of  yScrollIncrement;   furthermore,  the units for
              scrolling (e.g., the change in view  when  the  top
              and bottom arrows of a scrollbar are selected) will
              also be yScrollIncrement.  If  the  value  of  this
              option is less than or equal to zero, then vertical
              scrolling is unconstrained.


INTRODUCTION
       The canvas command creates a  new  window  (given  by  the
       pathName  argument)  and  makes  it  into a canvas widget.
       Additional options, described above, may be  specified  on
       the  command  line  or in the option database to configure
       aspects of the canvas such as its colors and  3-D  relief.
       The  canvas command returns its pathName argument.  At the
       time this command is invoked, there must not exist a  win-
       dow named pathName, but pathName's parent must exist.

       Canvas  widgets  implement  structured graphics.  A canvas
       displays any number of items, which  may  be  things  like
       rectangles, circles, lines, and text.  Items may be manip-
       ulated (e.g. moved or  re-colored)  and  commands  may  be
       associated  with  items in much the same way that the bind
       command allows commands to be bound to widgets.  For exam-
       ple, a particular command may be associated with the <But-
       ton-1> event so that the command is invoked whenever  but-
       ton 1 is pressed with the mouse cursor over an item.  This
       means that items in a canvas can have behaviors defined by
       the Tcl scripts bound to them.


DISPLAY LIST
       The items in a canvas are ordered for purposes of display,
       with the first item in the display  list  being  displayed
       first,  followed  by the next item in the list, and so on.
       Items later in the display list  obscure  those  that  are
       earlier  in the display list and are sometimes referred to
       as being ``on top'' of earlier items.  When a new item  is
       created  it  is  placed at the end of the display list, on
       top of everything else.  Widget commands may  be  used  to
       re-arrange the order of the display list.

       Window  items  are  an  exception to the above rules.  The
       underlying window systems require them always to be  drawn
       on top of other items.  In addition, the stacking order of
       window items is not affected by any of the  canvas  widget
       commands;  you  must  use  the raise and lower Tk commands
       instead.


ITEM IDS AND TAGS
       Items in a canvas widget may be named  in  either  of  two
       ways: by id or by tag.  Each item has a unique identifying
       number which is assigned to that item when it is  created.
       The  id  of an item never changes and id numbers are never
       re-used within the lifetime of a canvas widget.

       Each item may also have any number of tags associated with
       it.  A tag is just a string of characters, and it may take
       any form except that of an integer.  For example, ``x123''
       is  OK  but ``123'' isn't.  The same tag may be associated
       with many different items.  This is commonly done to group
       items  in  various  interesting  ways;   for  example, all
       selected items might be given the tag ``selected''.

       The tag all is implicitly associated with  every  item  in
       the  canvas;   it  may be used to invoke operations on all
       the items in the canvas.
       The tag current is managed automatically by Tk; it applies
       to the current item, which is the topmost item whose drawn
       area covers the position of  the  mouse  cursor.   If  the
       mouse  is not in the canvas widget or is not over an item,
       then no item has the current tag.

       When specifying items in canvas widget  commands,  if  the
       specifier is an integer then it is assumed to refer to the
       single item with that id.  If  the  specifier  is  not  an
       integer,  then  it is assumed to refer to all of the items
       in the canvas that have a tag matching the specifier.  The
       symbol  tagOrId is used below to indicate that an argument
       specifies either an id that selects a single item or a tag
       that  selects  zero  or  more items.  Some widget commands
       only operate on a single item at a time;   if  tagOrId  is
       specified  in  a  way  that names multiple items, then the
       normal behavior is for the command to use the first  (low-
       est)  of  these items in the display list that is suitable
       for the command.  Exceptions are noted in the widget  com-
       mand descriptions below.


COORDINATES
       All  coordinates  related to canvases are stored as float-
       ing-point numbers.  Coordinates and distances  are  speci-
       fied  in  screen  units,  which are floating-point numbers
       optionally followed by one of several letters.  If no let-
       ter  is  supplied  then the distance is in pixels.  If the
       letter is m then the distance is  in  millimeters  on  the
       screen;  if it is c then the distance is in centimeters; i
       means inches, and p means  printers  points  (1/72  inch).
       Larger  y-coordinates refer to points lower on the screen;
       larger x-coordinates refer to points farther to the right.


TRANSFORMATIONS
       Normally  the origin of the canvas coordinate system is at
       the upper-left corner of the window containing the canvas.
       It  is possible to adjust the origin of the canvas coordi-
       nate system relative to the origin of the window using the
       xview  and  yview widget commands;  this is typically used
       for scrolling.  Canvases do not support scaling  or  rota-
       tion  of the canvas coordinate system relative to the win-
       dow coordinate system.

       Individual items may be moved or scaled using widget  com-
       mands described below, but they may not be rotated.


INDICES
       Text  items support the notion of an index for identifying
       particular positions within the item.   Indices  are  used
       for  commands  such as inserting text, deleting a range of
       characters, and setting the insertion cursor position.  An
       index  may  be  specified  in any of a number of ways, and
       different types of items may support different  forms  for
       specifying  indices.   Text  items  support  the following
       forms for an index;  if you define new types of  text-like
       items,  it  would be advisable to support as many of these
       forms as practical.  Note that it is possible to refer  to
       the  character  just  after the last one in the text item;
       this is necessary for such tasks as inserting new text  at
       the end of the item.

       number    A  decimal  number  giving  the  position of the
                 desired  character  within  the  text  item.   0
                 refers  to  the  first  character, 1 to the next
                 character, and so on.  A number less than  0  is
                 treated as if it were zero, and a number greater
                 than the length of the text item is  treated  as
                 if it were equal to the length of the text item.

       end       Refers to the character just after the last  one
                 in the item (same as the number of characters in
                 the item).

       insert    Refers to the character just  before  which  the
                 insertion cursor is drawn in this item.

       sel.first Refers  to  the  first selected character in the
                 item.  If the selection isn't in this item  then
                 this form is illegal.

       sel.last  Refers  to  the  last  selected character in the
                 item.  If the selection isn't in this item  then
                 this form is illegal.

       @x,y      Refers  to the character at the point given by x
                 and y, where x and y are specified in the  coor-
                 dinate  system  of  the  canvas.  If x and y lie
                 outside the  coordinates  covered  by  the  text
                 item, then they refer to the first or last char-
                 acter in the line that is closest to  the  given
                 point.


WIDGET COMMAND
       The canvas 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 widget commands are possible for
       canvas widgets:

       pathName addtag tag searchSpec ?arg arg ...?
              For each item that meets the constraints  specified
              by  searchSpec and the args, add tag to the list of
              tags associated with the item if it  isn't  already
              present on that list.  It is possible that no items
              will satisfy the constraints  given  by  searchSpec
              and  args, in which case the command has no effect.
              This command returns an  empty  string  as  result.
              SearchSpec  and arg's may take any of the following
              forms:

              above tagOrId
                     Selects the item just after (above) the  one
                     given  by  tagOrId  in the display list.  If
                     tagOrId denotes more than one item, then the
                     last (topmost) of these items in the display
                     list is used.

              all    Selects all the items in the canvas.

              below tagOrId
                     Selects the item just before (below) the one
                     given  by  tagOrId  in the display list.  If
                     tagOrId denotes more than one item, then the
                     first (lowest) of these items in the display
                     list is used.

              closest x y ?halo? ?start?
                     Selects the item closest to the point  given
                     by x and y.  If more than one item is at the
                     same closest distance (e.g. two items  over-
                     lap  the  point), then the top-most of these
                     items (the last one in the display list)  is
                     used.  If halo is specified, then it must be
                     a non-negative value.  Any item closer  than
                     halo  to  the point is considered to overlap
                     it.  The start argument may be used to  step
                     circularly  through  all  the closest items.
                     If start is  specified,  it  names  an  item
                     using a tag or id (if by tag, it selects the
                     first item in  the  display  list  with  the
                     given  tag).   Instead of selecting the top-
                     most closest item, this form will select the
                     topmost  closest item that is below start in
                     the display list;  if no such  item  exists,
                     then  the  selection behaves as if the start
                     argument had not been specified.

              enclosed x1 y1 x2 y2
                     Selects all the  items  completely  enclosed
                     within  the  rectangular region given by x1,
                     y1, x2, and y2.  X1 must be no greater  then
                     x2 and y1 must be no greater than y2.

              overlapping x1 y1 x2 y2
                     Selects  all  the  items that overlap or are
                     enclosed within the rectangular region given
                     by  x1,  y1,  x2,  and  y2.   X1  must be no
                     greater then x2 and y1 must  be  no  greater
                     than y2.

              withtag tagOrId
                     Selects all the items given by tagOrId.

       pathName bbox tagOrId ?tagOrId tagOrId ...?
              Returns a list with four elements giving an approx-
              imate bounding box for all the items named  by  the
              tagOrId  arguments.   The list has the form ``x1 y1
              x2 y2'' such that the drawn areas of all the  named
              elements are within the region bounded by x1 on the
              left, x2 on the right, y1 on the top, and y2 on the
              bottom.   The  return  value  may  overestimate the
              actual bounding box by a few pixels.  If  no  items
              match any of the tagOrId arguments or if the match-
              ing items have empty bounding boxes (i.e. they have
              nothing   to  display)  then  an  empty  string  is
              returned.

       pathName bind tagOrId ?sequence? ?command?
              This command associates command with all the  items
              given  by  tagOrId  such  that  whenever  the event
              sequence given by sequence occurs for  one  of  the
              items  the  command  will  be invoked.  This widget
              command is similar to the bind command except  that
              it operates on items in a canvas rather than entire
              widgets.  See the bind manual  entry  for  complete
              details on the syntax of sequence and the substitu-
              tions performed on command before invoking it.   If
              all  arguments  are specified then a new binding is
              created, replacing any  existing  binding  for  the
              same  sequence  and tagOrId (if the first character
              of command is ``+'' then command augments an exist-
              ing  binding  rather  than  replacing it).  In this
              case the return value is an empty string.  If  com-
              mand  is  omitted then the command returns the com-
              mand associated with tagOrId and sequence (an error
              occurs  if there is no such binding).  If both com-
              mand and sequence  are  omitted  then  the  command
              returns a list of all the sequences for which bind-
              ings have been defined for tagOrId.

              The only events for which bindings may be specified
              are  those  related to the mouse and keyboard (such
              as Enter, Leave, ButtonPress, Motion, and KeyPress)
              or  virtual events.  The handling of events in can-
              vases uses the current item defined in ITEM IDS AND
              TAGS  above.  Enter and Leave events trigger for an
              item when it becomes the current item or ceases  to
              be  the  current  item;  note that these events are
              different than Enter and Leave events for  windows.
              Mouse-related  events  are  directed to the current
              item, if any.  Keyboard-related events are directed
              to  the  focus  item,  if any (see the focus widget
              command below for more  on  this).   If  a  virtual
              event  is used in a binding, that binding can trig-
              ger only if the virtual  event  is  defined  by  an
              underlying mouse-related or keyboard-related event.

              It is possible for multiple  bindings  to  match  a
              particular  event.   This could occur, for example,
              if one binding is associated with the item's id and
              another  is associated with one of the item's tags.
              When this occurs, all of the matching bindings  are
              invoked.   A binding associated with the all tag is
              invoked first, followed by one binding for each  of
              the  item's  tags (in order), followed by a binding
              associated with the item's id.  If there are multi-
              ple  matching  bindings for a single tag, then only
              the most specific binding is invoked.   A  continue
              command in a binding script terminates that script,
              and a break  command  terminates  that  script  and
              skips  any remaining scripts for the event, just as
              for the bind command.

              If bindings have been created for a  canvas  window
              using  the  bind  command, then they are invoked in
              addition to bindings created for the canvas's items
              using  the  bind  widget command.  The bindings for
              items will be invoked before any  of  the  bindings
              for the window as a whole.

       pathName canvasx screenx ?gridspacing?
              Given  a window x-coordinate in the canvas screenx,
              this command returns the canvas  x-coordinate  that
              is  displayed  at that location.  If gridspacing is
              specified, then the canvas coordinate is rounded to
              the nearest multiple of gridspacing units.

       pathName canvasy screeny ?gridspacing?
              Given  a  window y-coordinate in the canvas screeny
              this command returns the canvas  y-coordinate  that
              is  displayed  at that location.  If gridspacing is
              specified, then the canvas coordinate is rounded to
              the nearest multiple of gridspacing units.

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

       pathName coords tagOrId ?x0 y0 ...?
              Query or modify  the  coordinates  that  define  an
              item.   If  no coordinates are specified, this com-
              mand returns a list whose elements are the  coordi-
              nates of the item named by tagOrId.  If coordinates
              are specified, then they replace the current  coor-
              dinates  for  the named item.  If tagOrId refers to
              multiple items, then the first one in  the  display
              list is used.

       pathName create type x y ?x y ...? ?option value ...?
              Create  a  new  item in pathName of type type.  The
              exact format of the arguments after type depends on
              type,  but  usually they consist of the coordinates
              for one or more points, followed by  specifications
              for zero or more item options.  See the subsections
              on individual item types below for more on the syn-
              tax  of  this command.  This command returns the id
              for the new item.

       pathName dchars tagOrId first ?last?
              For each item given by tagOrId, delete the  charac-
              ters  in  the range given by first and last, inclu-
              sive.  If some of the items given by tagOrId  don't
              support  text  operations,  then  they are ignored.
              First and last are indices of characters within the
              item(s)  as described in INDICES above.  If last is
              omitted,  it  defaults  to  first.   This   command
              returns an empty string.

       pathName delete ?tagOrId tagOrId ...?
              Delete each of the items given by each tagOrId, and
              return an empty string.

       pathName dtag tagOrId ?tagToDelete?
              For each of the items given by tagOrId, delete  the
              tag  given  by  tagToDelete  from the list of those
              associated with the item.  If an item doesn't  have
              the  tag tagToDelete then the item is unaffected by
              the command.  If tagToDelete  is  omitted  then  it
              defaults to tagOrId.  This command returns an empty
              string.
       pathName find searchCommand ?arg arg ...?
              This command returns a list consisting of  all  the
              items   that  meet  the  constraints  specified  by
              searchCommand and arg's.   SearchCommand  and  args
              have  any  of the forms accepted by the addtag com-
              mand.  The items are returned  in  stacking  order,
              with the lowest item first.

       pathName focus ?tagOrId?
              Set the keyboard focus for the canvas widget to the
              item given by tagOrId.  If tagOrId refers  to  sev-
              eral items, then the focus is set to the first such
              item in the display list that supports  the  inser-
              tion  cursor.   If  tagOrId  doesn't  refer  to any
              items, or if none of  them  support  the  insertion
              cursor,  then  the focus isn't changed.  If tagOrId
              is an empty string, then the focus item is reset so
              that  no  item  has  the  focus.  If tagOrId is not
              specified then the command returns the id  for  the
              item  that  currently  has  the  focus, or an empty
              string if no item has the focus.

              Once the focus has been set to an  item,  the  item
              will  display the insertion cursor and all keyboard
              events will be directed to that  item.   The  focus
              item  within  a  canvas and the focus window on the
              screen (set with the  focus  command)  are  totally
              independent: a given item doesn't actually have the
              input focus unless (a) its canvas is the focus win-
              dow  and  (b) the item is the focus item within the
              canvas.  In most cases it is  advisable  to  follow
              the  focus widget command with the focus command to
              set the focus window to the canvas  (if  it  wasn't
              there already).

       pathName gettags tagOrId
              Return  a  list whose elements are the tags associ-
              ated with the item given by  tagOrId.   If  tagOrId
              refers  to  more  than  one item, then the tags are
              returned from the first such item  in  the  display
              list.  If tagOrId doesn't refer to any items, or if
              the item contains no tags, then an empty string  is
              returned.

       pathName icursor tagOrId index
              Set  the  position  of the insertion cursor for the
              item(s) given by tagOrId to just before the charac-
              ter  whose  position is given by index.  If some or
              all of the items given by tagOrId don't support  an
              insertion cursor then this command has no effect on
              them.  See INDICES above for a description  of  the
              legal forms for index.  Note:  the insertion cursor
              is only displayed in an item if that item currently
              has  the  keyboard  focus  (see  the widget command
              focus, below), but the cursor position may  be  set
              even  when  the  item doesn't have the focus.  This
              command returns an empty string.

       pathName index tagOrId index
              This command returns a decimal  string  giving  the
              numerical  index  within  tagOrId  corresponding to
              index.  Index gives a textual  description  of  the
              desired  position  as  described  in INDICES above.
              The return value is guaranteed to lie between 0 and
              the  number  of  characters within the item, inclu-
              sive.  If tagOrId refers to  multiple  items,  then
              the  index is processed in the first of these items
              that supports indexing operations (in display  list
              order).

       pathName insert tagOrId beforeThis string
              For each of the items given by tagOrId, if the item
              supports text insertion  then  string  is  inserted
              into  the  item's  text  just  before the character
              whose index is beforeThis.  See INDICES  above  for
              information about the forms allowed for beforeThis.
              This command returns an empty string.

       pathName itemcget tagOrId option
              Returns the  current  value  of  the  configuration
              option  for the item given by tagOrId whose name is
              option.  This command is similar to the cget widget
              command except that it applies to a particular item
              rather than the widget as a whole.  Option may have
              any  of  the  values  accepted by the create widget
              command when the item was created.  If tagOrId is a
              tag  that  refers  to more than one item, the first
              (lowest) such item is used.

       pathName itemconfigure tagOrId  ?option?  ?value?  ?option
              value ...?
              This command is similar  to  the  configure  widget
              command   except  that  it  modifies  item-specific
              options for the items given by tagOrId  instead  of
              modifying  options  for  the overall canvas widget.
              If no option is specified, returns a list  describ-
              ing all of the available options for the first item
              given by tagOrId (see Tk_ConfigureInfo for informa-
              tion  on  the  format  of this list).  If option is
              specified 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 each of the items  given
              by  tagOrId;   in  this case the command returns an
              empty string.  The options and values are the  same
              as  those  permissible in the create widget command
              when the item(s) were  created;  see  the  sections
              describing  individual item types below for details
              on the legal options.

       pathName lower tagOrId ?belowThis?
              Move all of the items given by  tagOrId  to  a  new
              position  in  the display list just before the item
              given by belowThis.  If tagOrId refers to more than
              one  item then all are moved but the relative order
              of the moved items will not be changed.   BelowThis
              is a tag or id;  if it refers to more than one item
              then the first (lowest) of these items in the  dis-
              play  list  is used as the destination location for
              the moved items.  Note: this command has no  effect
              on window items.  Window items always obscure other
              item types, and the stacking order of window  items
              is  determined by the raise and lower commands, not
              the raise and lower widget commands  for  canvases.
              This command returns an empty string.

       pathName move tagOrId xAmount yAmount
              Move each of the items given by tagOrId in the can-
              vas coordinate space by adding xAmount  to  the  x-
              coordinate  of  each point associated with the item
              and yAmount to the y-coordinate of each point asso-
              ciated  with  the  item.   This  command returns an
              empty string.

       pathName postscript ?option value option value ...?
              Generate a Postscript representation  for  part  or
              all  of  the canvas.  If the -file option is speci-
              fied then the Postscript is written to a  file  and
              an   empty   string  is  returned;   otherwise  the
              Postscript is returned as the result  of  the  com-
              mand.   If  the interpreter that owns the canvas is
              marked as safe, the  operation  will  fail  because
              safe  interpreters  are not allowed to write files.
              If the -channel option is specified,  the  argument
              denotes  the  name  of a channel already opened for
              writing. The Postscript is written to that channel,
              and the channel is left open for further writing at
              the end of the operation.  The Postscript  is  cre-
              ated  in Encapsulated Postscript form using version
              3.0 of the Document Structuring Conventions.  Note:
              by  default Postscript is only generated for infor-
              mation that appears in the canvas's window  on  the
              screen.   If  the  canvas is freshly created it may
              still have its initial size of 1x1 pixel so nothing
              will  appear in the Postscript.  To get around this
              problem either invoke the "update" command to  wait
              for  the  canvas window to reach its final size, or
              else use the -width and -height options to  specify
              the  area of the canvas to print.  The option-value
              argument pairs provide  additional  information  to
              control  the generation of Postscript.  The follow-
              ing options are supported:

              -colormap varName
                     VarName must be the name of an  array  vari-
                     able  that  specifies a color mapping to use
                     in the Postscript.  Each element of  varName
                     must  consist  of  Postscript  code to set a
                     particular color value (e.g. ``1.0  1.0  0.0
                     setrgbcolor'').    When   outputting   color
                     information in the Postscript, Tk checks  to
                     see  if  there is an element of varName with
                     the same name as the color.  If so, Tk  uses
                     the  value  of the element as the Postscript
                     command to set the color.   If  this  option
                     hasn't  been specified, or if there isn't an
                     entry in varName for a given color, then  Tk
                     uses  the  red,  green, and blue intensities
                     from the X color.

              -colormode mode
                     Specifies how to output  color  information.
                     Mode  must  be  either color (for full color
                     output), gray (convert all colors  to  their
                     gray-scale equivalents) or mono (convert all
                     colors to black or white).

              -file fileName
                     Specifies the name of the file in  which  to
                     write  the Postscript.  If this option isn't
                     specified then the Postscript is returned as
                     the  result  of the command instead of being
                     written to a file.

              -fontmap varName
                     VarName must be the name of an  array  vari-
                     able that specifies a font mapping to use in
                     the Postscript.   Each  element  of  varName
                     must  consist  of  a  Tcl list with two ele-
                     ments, which are the name and point size  of
                     a    Postscript   font.    When   outputting
                     Postscript commands for a  particular  font,
                     Tk checks to see if varName contains an ele-
                     ment with the same name  as  the  font.   If
                     there  is  such  an  element,  then the font
                     information contained  in  that  element  is
                     used   in   the  Postscript.   Otherwise  Tk
                     attempts to guess what  Postscript  font  to
                     use.   Tk's  guesses generally only work for
                     well-known fonts such as Times and Helvetica
                     and  Courier,  and  only  if the X font name
                     does not omit  any  dashes  up  through  the
                     point        size.        For       example,
                     -*-Courier-Bold-R-Normal--*-120-* will  work
                     but  *Courier-Bold-R-Normal*120*  will  not;
                     Tk needs the dashes to parse the font name).

              -height size
                     Specifies the height of the area of the can-
                     vas to print.  Defaults to the height of the
                     canvas window.

              -pageanchor anchor
                     Specifies which point of the printed area of
                     the canvas should appear over the  position-
                     ing point on the page (which is given by the
                     -pagex and -pagey  options).   For  example,
                     -pageanchor  n  means that the top center of
                     the area of the canvas being printed (as  it
                     appears in the canvas window) should be over
                     the positioning point. Defaults to center.

              -pageheight size
                     Specifies  that  the  Postscript  should  be
                     scaled  in  both x and y so that the printed
                     area is size high on  the  Postscript  page.
                     Size  consists  of  a  floating-point number
                     followed by c for centimeters, i for inches,
                     m  for  millimeters,  or  p  or  nothing for
                     printer's points (1/72 inch).   Defaults  to
                     the  height  of  the  printed  area  on  the
                     screen.  If both -pageheight and  -pagewidth
                     are  specified  then  the  scale factor from
                     -pagewidth is used (non-uniform  scaling  is
                     not implemented).

              -pagewidth size
                     Specifies  that  the  Postscript  should  be
                     scaled in both x and y so that  the  printed
                     area  is  size  wide on the Postscript page.
                     Size has the same form as  for  -pageheight.
                     Defaults to the width of the printed area on
                     the  screen.   If   both   -pageheight   and
                     -pagewidth are specified then the scale fac-
                     tor from -pagewidth   is  used  (non-uniform
                     scaling is not implemented).

              -pagex position
                     Position gives the x-coordinate of the posi-
                     tioning point on the Postscript page,  using
                     any  of  the  forms allowed for -pageheight.
                     Used in  conjunction  with  the  -pagey  and
                     -pageanchor  options  to determine where the
                     printed area appears on the Postscript page.
                     Defaults to the center of the page.
              -pagey position
                     Position gives the y-coordinate of the posi-
                     tioning point on the Postscript page,  using
                     any  of  the  forms allowed for -pageheight.
                     Used in  conjunction  with  the  -pagex  and
                     -pageanchor  options  to determine where the
                     printed area appears on the Postscript page.
                     Defaults to the center of the page.

              -rotate boolean
                     Boolean  specifies  whether the printed area
                     is to be rotated 90 degrees.  In non-rotated
                     output  the  x-axis of the printed area runs
                     along  the  short  dimension  of  the   page
                     (``portrait''  orientation); in rotated out-
                     put the x-axis runs along the long dimension
                     of  the  page  (``landscape''  orientation).
                     Defaults to non-rotated.

              -width size
                     Specifies the width of the area of the  can-
                     vas  to print.  Defaults to the width of the
                     canvas window.

              -x position
                     Specifies the x-coordinate of the left  edge
                     of  the  area  of  the  canvas that is to be
                     printed, in canvas coordinates,  not  window
                     coordinates.   Defaults to the coordinate of
                     the left edge of the window.

              -y position
                     Specifies the y-coordinate of the  top  edge
                     of  the  area  of  the  canvas that is to be
                     printed, in canvas coordinates,  not  window
                     coordinates.   Defaults to the coordinate of
                     the top edge of the window.

       pathName raise tagOrId ?aboveThis?
              Move all of the items given by  tagOrId  to  a  new
              position  in  the  display list just after the item
              given by aboveThis.  If tagOrId refers to more than
              one  item then all are moved but the relative order
              of the moved items will not be changed.   AboveThis
              is a tag or id;  if it refers to more than one item
              then the last (topmost) of these items in the  dis-
              play  list  is used as the destination location for
              the moved items.  Note: this command has no  effect
              on window items.  Window items always obscure other
              item types, and the stacking order of window  items
              is  determined by the raise and lower commands, not
              the raise and lower widget commands  for  canvases.
              This command returns an empty string.
       pathName scale tagOrId xOrigin yOrigin xScale yScale
              Rescale all of the items given by tagOrId in canvas
              coordinate space.  XOrigin and yOrigin identify the
              origin  for  the  scaling  operation and xScale and
              yScale identify the scale factors  for  x-  and  y-
              coordinates,  respectively  (a  scale factor of 1.0
              implies no change to that coordinate).  For each of
              the  points defining each item, the x-coordinate is
              adjusted to change the distance from xOrigin  by  a
              factor  of xScale.  Similarly, each y-coordinate is
              adjusted to change the distance from yOrigin  by  a
              factor  of  yScale.   This command returns an empty
              string.

       pathName scan option args
              This command is used to implement scanning on  can-
              vases.  It has two forms, depending on option:

              pathName scan mark x y
                     Records  x  and  y  and the canvas's current
                     view;  used in conjunction with  later  scan
                     dragto  commands.  Typically this command is
                     associated with a mouse button press in  the
                     widget  and  x  and y are the coordinates of
                     the mouse.  It returns an empty string.

              pathName scan dragto x y.
                     This command computes the difference between
                     its  x  and y arguments (which are typically
                     mouse coordinates) and the x and y arguments
                     to  the  last scan mark command for the wid-
                     get.  It then adjusts the view by  10  times
                     the difference in coordinates.  This command
                     is typically associated  with  mouse  motion
                     events  in the widget, to produce the effect
                     of dragging the canvas at high speed through
                     its  window.   The  return value is an empty
                     string.

       pathName select option ?tagOrId arg?
              Manipulates the selection in one of  several  ways,
              depending  on  option.  The command may take any of
              the forms described below.  In all of the  descrip-
              tions  below,  tagOrId  must  refer to an item that
              supports indexing and selection;  if it  refers  to
              multiple  items  then  the first of these that sup-
              ports indexing and the selection  is  used.   Index
              gives  a  textual  description of a position within
              tagOrId, as described in INDICES above.

              pathName select adjust tagOrId index
                     Locate the end of the selection  in  tagOrId
                     nearest to the character given by index, and
                     adjust that end of the selection  to  be  at
                     index  (i.e.  including but not going beyond
                     index).  The other end of the  selection  is
                     made  the  anchor point for future select to
                     commands.  If the selection isn't  currently
                     in  tagOrId  then  this  command behaves the
                     same  as  the  select  to  widget   command.
                     Returns an empty string.

              pathName select clear
                     Clear the selection if it is in this widget.
                     If the selection isn't in this  widget  then
                     the command has no effect.  Returns an empty
                     string.

              pathName select from tagOrId index
                     Set the selection anchor point for the  wid-
                     get to be just before the character given by
                     index in the item given  by  tagOrId.   This
                     command  doesn't  change  the selection;  it
                     just sets the fixed end of the selection for
                     future select to commands.  Returns an empty
                     string.

              pathName select item
                     Returns the id of the selected item, if  the
                     selection  is in an item in this canvas.  If
                     the selection is not in this canvas then  an
                     empty string is returned.

              pathName select to tagOrId index
                     Set  the selection to consist of those char-
                     acters  of  tagOrId  between  the  selection
                     anchor  point  and index.  The new selection
                     will include the character given  by  index;
                     it  will  include the character given by the
                     anchor point only if index is  greater  than
                     or  equal  to  the anchor point.  The anchor
                     point  is  determined  by  the  most  recent
                     select  adjust  or  select  from command for
                     this widget.  If the selection anchor  point
                     for  the  widget isn't currently in tagOrId,
                     then it is set to the same  character  given
                     by index.  Returns an empty string.

       pathName type tagOrId
              Returns the type of the item given by tagOrId, such
              as rectangle or text.  If tagOrId  refers  to  more
              than  one  item, then the type of the first item in
              the display list is returned.  If  tagOrId  doesn't
              refer  to  any items at all then an empty string is
              returned.

       pathName xview  ?args?
              This command  is  used  to  query  and  change  the
              horizontal position of the information displayed in
              the canvas's window.  It can take any of  the  fol-
              lowing forms:

              pathName xview
                     Returns  a  list  containing  two  elements.
                     Each element is a real  fraction  between  0
                     and  1;  together they describe the horizon-
                     tal span that is visible in the window.  For
                     example,  if the first element is .2 and the
                     second element is .6, 20%  of  the  canvas's
                     area   (as   defined  by  the  -scrollregion
                     option) is off-screen to the left, the  mid-
                     dle 40% is visible in the window, and 40% of
                     the  canvas  is  off-screen  to  the  right.
                     These  are the same values passed to scroll-
                     bars via the -xscrollcommand option.

              pathName xview moveto fraction
                     Adjusts the view in the window so that frac-
                     tion  of  the  total  width of the canvas is
                     off-screen to the left.  Fraction must be  a
                     fraction between 0 and 1.

              pathName xview scroll number what
                     This  command  shifts the view in the window
                     left or right according to number and  what.
                     Number  must  be  an  integer.  What must be
                     either units or pages or an abbreviation  of
                     one  of  these.   If what is units, the view
                     adjusts  left  or  right  in  units  of  the
                     xScrollIncrement  option,  if  it is greater
                     than zero, or in units of one-tenth the win-
                     dow's  width  otherwise.   If  what is pages
                     then the view  adjusts  in  units  of  nine-
                     tenths  the  window's  width.   If number is
                     negative then  information  farther  to  the
                     left  becomes  visible;   if  it is positive
                     then  information  farther  to   the   right
                     becomes visible.

       pathName yview ?args?
              This command is used to query and change the verti-
              cal position of the information  displayed  in  the
              canvas's  window.  It can take any of the following
              forms:

              pathName yview
                     Returns  a  list  containing  two  elements.
                     Each  element  is  a real fraction between 0
                     and 1;  together they describe the  vertical
                     span  that  is  visible  in the window.  For
                     example, if the first element is .6 and  the
                     second element is 1.0, the lowest 40% of the
                     canvas's area (as defined by the  -scrollre-
                     gion  option)  is  visible  in  the  window.
                     These are the same values passed to  scroll-
                     bars via the -yscrollcommand option.

              pathName yview moveto fraction
                     Adjusts the view in the window so that frac-
                     tion of the canvas's area is  off-screen  to
                     the  top.   Fraction is a fraction between 0
                     and 1.

              pathName yview scroll number what
                     This command adjusts the view in the  window
                     up  or  down  according  to number and what.
                     Number must be an  integer.   What  must  be
                     either  units  or  pages.  If what is units,
                     the view adjusts up or down in units of  the
                     yScrollIncrement  option,  if  it is greater
                     than zero, or in units of one-tenth the win-
                     dow's  height  otherwise.   If what is pages
                     then the view  adjusts  in  units  of  nine-
                     tenths  the  window's  height.  If number is
                     negative  then  higher  information  becomes
                     visible;   if  it  is  positive  then  lower
                     information becomes visible.


OVERVIEW OF ITEM TYPES
       The sections below describe the  various  types  of  items
       supported by canvas widgets.  Each item type is character-
       ized by two things: first, the form of the create  command
       used  to  create instances of the type;  and second, a set
       of configuration options for items of that type, which may
       be  used  in the create and itemconfigure widget commands.
       Most items don't support indexing or selection or the com-
       mands  related  to  them, such as index and insert.  Where
       items do support these facilities, it is noted  explicitly
       in  the  descriptions  below  (at present, only text items
       provide this support).


ARC ITEMS
       Items of type arc appear  on  the  display  as  arc-shaped
       regions.   An arc is a section of an oval delimited by two
       angles (specified by the -start and -extent  options)  and
       displayed  in one of several ways (specified by the -style
       option).  Arcs are created with  widget  commands  of  the
       following form:
              pathName create arc x1 y1 x2 y2 ?option value option value ...?
       The  arguments  x1, y1, x2, and y2 give the coordinates of
       two diagonally opposite corners of  a  rectangular  region
       enclosing  the oval that defines the arc.  After the coor-
       dinates there may be any  number  of  option-value  pairs,
       each  of  which  sets one of the configuration options for
       the item.  These same option-value pairs may  be  used  in
       itemconfigure widget commands to change the item's config-
       uration.  The following options are supported for arcs:

       -extent degrees
              Specifies the size of the angular range occupied by
              the  arc.   The  arc's  range  extends  for degrees
              degrees counter-clockwise from the  starting  angle
              given  by  the -start option.  Degrees may be nega-
              tive.  If it is greater than 360 or less than -360,
              then degrees modulo 360 is used as the extent.

       -fill color
              Fill  the  region of the arc with color.  Color may
              have any of the forms accepted by Tk_GetColor.   If
              color  is  an empty string (the default), then then
              the arc will not be filled.

       -outline color
              Color specifies a color  to  use  for  drawing  the
              arc's  outline;   it  may  have  any  of  the forms
              accepted by Tk_GetColor.  This option  defaults  to
              black.   If  color  is specified as an empty string
              then no outline is drawn for the arc.

       -outlinestipple bitmap
              Indicates that the outline for the  arc  should  be
              drawn  with a stipple pattern; bitmap specifies the
              stipple  pattern  to  use,  in  any  of  the  forms
              accepted  by  Tk_GetBitmap.  If the -outline option
              hasn't been  specified  then  this  option  has  no
              effect.    If   bitmap  is  an  empty  string  (the
              default), then the outline  is  drawn  in  a  solid
              fashion.

       -start degrees
              Specifies  the beginning of the angular range occu-
              pied by the arc.  Degrees  is  given  in  units  of
              degrees   measured   counter-clockwise   from   the
              3-o'clock position;  it may be either  positive  or
              negative.

       -stipple bitmap
              Indicates  that the arc should be filled in a stip-
              ple pattern; bitmap specifies the  stipple  pattern
              to  use,  in  any  of the forms accepted by Tk_Get-
              Bitmap.  If the -fill option hasn't been  specified
              then  this  option  has no effect.  If bitmap is an
              empty string (the default), then filling is done in
              a solid fashion.

       -style type
              Specifies how to draw the arc.  If type is pieslice
              (the default) then the arc's region is defined by a
              section  of the oval's perimeter plus two line seg-
              ments, one between the center of the oval and  each
              end  of  the  perimeter  section.  If type is chord
              then the arc's region is defined by  a  section  of
              the  oval's  perimeter  plus  a single line segment
              connecting the two end points of the perimeter sec-
              tion.   If  type  is arc then the arc's region con-
              sists of a section of the perimeter alone.  In this
              last case the -fill option is ignored.

       -tags tagList
              Specifies  a  set  of  tags  to  apply to the item.
              TagList consists of a  list  of  tag  names,  which
              replace  any  existing  tags for the item.  TagList
              may be an empty list.

       -width outlineWidth
              Specifies the width of  the  outline  to  be  drawn
              around  the  arc's  region,  in  any  of  the forms
              described in the COORDINATES section above.  If the
              -outline  option  has  been  specified  as an empty
              string then this option has no effect.   Wide  out-
              lines  will  be  drawn centered on the edges of the
              arc's region.  This option defaults to 1.0.


BITMAP ITEMS
       Items of type bitmap appear on the display as images  with
       two  colors,  foreground and background.  Bitmaps are cre-
       ated with widget commands of the following form:
              pathName create bitmap x y ?option value option value ...?
       The arguments x and y specify the coordinates of  a  point
       used  to  position  the  bitmap  on  the  display (see the
       -anchor option below for more information on  how  bitmaps
       are  displayed).   After  the coordinates there may be any
       number of option-value pairs, each of which  sets  one  of
       the  configuration  options  for  the  item.   These  same
       option-value pairs may be  used  in  itemconfigure  widget
       commands  to change the item's configuration.  The follow-
       ing options are supported for bitmaps:

       -anchor anchorPos
              AnchorPos tells how to position the bitmap relative
              to the positioning point for the item;  it may have
              any of the forms  accepted  by  Tk_GetAnchor.   For
              example,  if anchorPos is center then the bitmap is
              centered on the point;  if anchorPos is n then  the
              bitmap  will  be drawn so that its top center point
              is at the positioning point.  This option  defaults
              to center.

       -background color
              Specifies  a  color  to  use for each of the bitmap
              pixels whose value is 0.  Color may have any of the
              forms  accepted  by  Tk_GetColor.   If  this option
              isn't specified, or if it is specified as an  empty
              string,  then nothing is displayed where the bitmap
              pixels are 0;  this produces a transparent  effect.

       -bitmap bitmap
              Specifies  the  bitmap  to  display  in  the  item.
              Bitmap may  have  any  of  the  forms  accepted  by
              Tk_GetBitmap.

       -foreground color
              Specifies  a  color  to  use for each of the bitmap
              pixels whose value is 1.  Color may have any of the
              forms  accepted  by  Tk_GetColor  and  defaults  to
              black.

       -tags tagList
              Specifies a set of  tags  to  apply  to  the  item.
              TagList  consists  of  a  list  of tag names, which
              replace any existing tags for  the  item.   TagList
              may be an empty list.


IMAGE ITEMS
       Items  of  type image are used to display images on a can-
       vas.  Images are created with widget commands of the  fol-
       lowing form:
              pathName create image x y ?option value option value ...?
       The  arguments  x and y specify the coordinates of a point
       used to position the image on the display (see the -anchor
       option below for more information).  After the coordinates
       there may be any number of  option-value  pairs,  each  of
       which  sets one of the configuration options for the item.
       These same option-value pairs may be used in itemconfigure
       widget  commands  to change the item's configuration.  The
       following options are supported for images:

       -anchor anchorPos
              AnchorPos tells how to position the image  relative
              to the positioning point for the item;  it may have
              any of the forms  accepted  by  Tk_GetAnchor.   For
              example,  if  anchorPos is center then the image is
              centered on the point;  if anchorPos is n then  the
              image will be drawn so that its top center point is
              at the positioning point.  This option defaults  to
              center.

       -image name
              Specifies  the  name of the image to display in the
              item.  This image must have been created previously
              with the image create command.

       -tags tagList
              Specifies  a  set  of  tags  to  apply to the item.
              TagList consists of a  list  of  tag  names,  which
              replace  any existing tags for the item;  it may be
              an empty list.


LINE ITEMS
       Items of type line appear on the display as  one  or  more
       connected line segments or curves.  Lines are created with
       widget commands of the following form:
              pathName create line x1 y1... xn yn ?option value option value ...?
       The arguments x1 through yn give  the  coordinates  for  a
       series  of  two  or  more points that describe a series of
       connected line segments.  After the coordinates there  may
       be  any  number  of option-value pairs, each of which sets
       one of the configuration options for the item.  These same
       option-value  pairs  may  be  used in itemconfigure widget
       commands to change the item's configuration.  The  follow-
       ing options are supported for lines:

       -arrow where
              Indicates whether or not arrowheads are to be drawn
              at one or both ends of the line.  Where  must  have
              one  of  the values none (for no arrowheads), first
              (for an arrowhead at the first point of the  line),
              last  (for  an  arrowhead  at the last point of the
              line), or both (for arrowheads at both ends).  This
              option defaults to none.

       -arrowshape shape
              This  option indicates how to draw arrowheads.  The
              shape argument must be a list with three  elements,
              each  specifying  a  distance  in  any of the forms
              described in the COORDINATES  section  above.   The
              first  element of the list gives the distance along
              the line from the neck of the arrowhead to its tip.
              The  second  element  gives  the distance along the
              line from the trailing points of the  arrowhead  to
              the  tip,  and the third element gives the distance
              from the outside edge of the line to  the  trailing
              points.   If  this  option  isn't specified then Tk
              picks a ``reasonable'' shape.

       -capstyle style
              Specifies the ways in which caps are to be drawn at
              the  endpoints  of the line.  Style may have any of
              the forms accepted by  Tk_GetCapStyle  (butt,  pro-
              jecting, or round).  If this option isn't specified
              then it defaults to  butt.   Where  arrowheads  are
              drawn the cap style is ignored.

       -fill color
              Color  specifies  a  color  to  use for drawing the
              line; it may have any of the  forms  acceptable  to
              Tk_GetColor.   It  may  also be an empty string, in
              which case the  line  will  be  transparent.   This
              option defaults to black.

       -joinstyle style
              Specifies  the ways in which joints are to be drawn
              at the vertices of the line.  Style may have any of
              the forms accepted by Tk_GetCapStyle (bevel, miter,
              or round).  If this option isn't specified then  it
              defaults  to  miter.  If the line only contains two
              points then this option is irrelevant.

       -smooth boolean
              Boolean must have one  of  the  forms  accepted  by
              Tk_GetBoolean.   It  indicates  whether  or not the
              line should be drawn as a curve.  If so,  the  line
              is  rendered  as  a  set  of parabolic splines: one
              spline is drawn for the first and second line  seg-
              ments,  one  for  the  second and third, and so on.
              Straight-line segments can be  generated  within  a
              curve  by duplicating the end-points of the desired
              line segment.

       -splinesteps number
              Specifies the  degree  of  smoothness  desired  for
              curves:  each spline will be approximated with num-
              ber line segments.  This option is  ignored  unless
              the -smooth option is true.

       -stipple bitmap
              Indicates that the line should be filled in a stip-
              ple pattern; bitmap specifies the  stipple  pattern
              to  use,  in  any  of the forms accepted by Tk_Get-
              Bitmap.   If  bitmap  is  an  empty   string   (the
              default),  then filling is done in a solid fashion.

       -tags tagList
              Specifies a set of  tags  to  apply  to  the  item.
              TagList  consists  of  a  list  of tag names, which
              replace any existing tags for  the  item.   TagList
              may be an empty list.

       -width lineWidth
              LineWidth  specifies  the width of the line, in any
              of the forms described in the  COORDINATES  section
              above.   Wide  lines  will be drawn centered on the
              path specified by the points.  If this option isn't
              specified then it defaults to 1.0.


OVAL ITEMS
       Items  of  type oval appear as circular or oval regions on
       the display.  Each oval may have an outline,  a  fill,  or
       both.   Ovals are created with widget commands of the fol-
       lowing form:
              pathName create oval x1 y1 x2 y2 ?option value option value ...?
       The arguments x1, y1, x2, and y2 give the  coordinates  of
       two  diagonally  opposite  corners of a rectangular region
       enclosing the oval.  The oval will  include  the  top  and
       left  edges of the rectangle not the lower or right edges.
       If the region is square then the resulting oval is  circu-
       lar;  otherwise it is elongated in shape.  After the coor-
       dinates there may be any  number  of  option-value  pairs,
       each  of  which  sets one of the configuration options for
       the item.  These same option-value pairs may  be  used  in
       itemconfigure widget commands to change the item's config-
       uration.  The following options are supported for ovals:

       -fill color
              Fill the area of the oval with  color.   Color  may
              have  any of the forms accepted by Tk_GetColor.  If
              color is an empty string (the default),  then  then
              the oval will not be filled.

       -outline color
              Color  specifies  a  color  to  use for drawing the
              oval's outline;  it  may  have  any  of  the  forms
              accepted  by  Tk_GetColor.  This option defaults to
              black.  If color is an empty string then no outline
              will be drawn for the oval.

       -stipple bitmap
              Indicates that the oval should be filled in a stip-
              ple pattern; bitmap specifies the  stipple  pattern
              to  use,  in  any  of the forms accepted by Tk_Get-
              Bitmap.  If the -fill option hasn't been  specified
              then  this  option  has no effect.  If bitmap is an
              empty string (the default), then filling is done in
              a solid fashion.

       -tags tagList
              Specifies  a  set  of  tags  to  apply to the item.
              TagList consists of a  list  of  tag  names,  which
              replace  any  existing  tags for the item.  TagList
              may be an empty list.

       -width outlineWidth
              outlineWidth specifies the width of the outline  to
              be  drawn  around  the  oval,  in  any of the forms
              described in the COORDINATES section above.  If the
              -outline  option  hasn't  been  specified then this
              option has no effect.  Wide outlines are drawn cen-
              tered  on  the oval path defined by x1, y1, x2, and
              y2.  This option defaults to 1.0.


POLYGON ITEMS
       Items of type polygon appear as polygonal or curved filled
       regions  on the display.  Polygons are created with widget
       commands of the following form:
              pathName create polygon x1 y1 ... xn yn ?option value option value ...?
       The arguments x1 through yn specify  the  coordinates  for
       three  or  more  points that define a closed polygon.  The
       first and last points may be the same;  whether  they  are
       or  not,  Tk  will  draw  the polygon as a closed polygon.
       After  the  coordinates  there  may  be  any   number   of
       option-value pairs, each of which sets one of the configu-
       ration options for  the  item.   These  same  option-value
       pairs  may  be  used  in  itemconfigure widget commands to
       change the item's configuration.   The  following  options
       are supported for polygons:

       -fill color
              Color specifies a color to use for filling the area
              of the polygon;  it  may  have  any  of  the  forms
              acceptable  to  Tk_GetColor.   If color is an empty
              string then the polygon will be transparent.   This
              option defaults to black.

       -outline color
              Color  specifies  a  color  to  use for drawing the
              polygon's outline;  it may have any  of  the  forms
              accepted  by  Tk_GetColor.   If  color  is an empty
              string then no outline will be drawn for the  poly-
              gon.  This option defaults to empty (no outline).

       -smooth boolean
              Boolean  must  have  one  of  the forms accepted by
              Tk_GetBoolean It indicates whether or not the poly-
              gon  should  be  drawn with a curved perimeter.  If
              so, the outline of the polygon  becomes  a  set  of
              parabolic  splines,  one  spline  for the first and
              second line segments, one for the second and third,
              and so on.  Straight-line segments can be generated
              in a smoothed polygon by duplicating the end-points
              of the desired line segment.

       -splinesteps number
              Specifies  the  degree  of  smoothness  desired for
              curves:  each spline will be approximated with num-
              ber  line  segments.  This option is ignored unless
              the -smooth option is true.

       -stipple bitmap
              Indicates that the polygon should be  filled  in  a
              stipple  pattern; bitmap specifies the stipple pat-
              tern to use,  in  any  of  the  forms  accepted  by
              Tk_GetBitmap.   If  bitmap  is an empty string (the
              default), then filling is done in a solid  fashion.

       -tags tagList
              Specifies  a  set  of  tags  to  apply to the item.
              TagList consists of a  list  of  tag  names,  which
              replace  any  existing  tags for the item.  TagList
              may be an empty list.

       -width outlineWidth
              OutlineWidth specifies the width of the outline  to
              be  drawn  around  the polygon, in any of the forms
              described in the COORDINATES section above.  If the
              -outline  option  hasn't  been  specified then this
              option has no effect.  This option defaults to 1.0.

       Polygon items are different from other items such as rect-
       angles, ovals and arcs in that interior points are consid-
       ered  to be ``inside'' a polygon (e.g. for purposes of the
       find closest and find overlapping widget commands) even if
       it  is not filled.  For most other item types, an interior
       point is considered to be inside the item only if the item
       is  filled or if it has neither a fill nor an outline.  If
       you would like an unfilled polygon whose  interior  points
       are  not  considered  to be inside the polygon, use a line
       item instead.


RECTANGLE ITEMS
       Items of type rectangle appear as rectangular  regions  on
       the  display.  Each rectangle may have an outline, a fill,
       or both.  Rectangles are created with widget  commands  of
       the following form:
              pathName create rectangle x1 y1 x2 y2 ?option value option value ...?
       The  arguments  x1, y1, x2, and y2 give the coordinates of
       two diagonally opposite  corners  of  the  rectangle  (the
       rectangle  will  include  its upper and left edges but not
       its lower or right edges).  After  the  coordinates  there
       may  be  any  number  of option-value pairs, each of which
       sets one of the configuration options for the item.  These
       same  option-value pairs may be used in itemconfigure wid-
       get commands to change the item's configuration.  The fol-
       lowing options are supported for rectangles:

       -fill color
              Fill  the  area  of the rectangle with color, which
              may be specified in any of the  forms  accepted  by
              Tk_GetColor.   If  color  is  an  empty string (the
              default), then the rectangle will not be filled.

       -outline color
              Draw an outline around the edge of the rectangle in
              color.  Color may have any of the forms accepted by
              Tk_GetColor.  This option defaults  to  black.   If
              color  is  an  empty string then no outline will be
              drawn for the rectangle.

       -stipple bitmap
              Indicates that the rectangle should be filled in  a
              stipple   pattern;  bitmap  specifies  the  stipple
              pattern to use, in any of  the  forms  accepted  by
              Tk_GetBitmap.   If  the  -fill  option  hasn't been
              specified then  this  option  has  no  effect.   If
              bitmap is an empty string (the default), then fill-
              ing is done in a solid fashion.

       -tags tagList
              Specifies a set of  tags  to  apply  to  the  item.
              TagList  consists  of  a  list  of tag names, which
              replace any existing tags for  the  item.   TagList
              may be an empty list.

       -width outlineWidth
              OutlineWidth  specifies the width of the outline to
              be drawn around the rectangle, in any of the  forms
              described in the COORDINATES section above.  If the
              -outline option hasn't  been  specified  then  this
              option has no effect.  Wide outlines are drawn cen-
              tered on the rectangular path defined  by  x1,  y1,
              x2, and y2.  This option defaults to 1.0.


TEXT ITEMS
       A  text item displays a string of characters on the screen
       in one or more lines.  Text  items  support  indexing  and
       selection,  along  with  the following text-related canvas
       widget commands:  dchars, focus, icursor,  index,  insert,
       select.   Text  items  are created with widget commands of
       the following form:
              pathName create text x y ?option value option value ...?
       The arguments x and y specify the coordinates of  a  point
       used  to position the text on the display (see the options
       below for more information  on  how  text  is  displayed).
       After   the   coordinates  there  may  be  any  number  of
       option-value pairs, each of which sets one of the configu-
       ration  options  for  the  item.   These same option-value
       pairs may be used  in  itemconfigure  widget  commands  to
       change  the  item's  configuration.  The following options
       are supported for text items:

       -anchor anchorPos
              AnchorPos tells how to position the  text  relative
              to the positioning point for the text;  it may have
              any of the forms  accepted  by  Tk_GetAnchor.   For
              example,  if  anchorPos  is center then the text is
              centered on the point;  if anchorPos is n then  the
              text  will  be drawn such that the top center point
              of the rectangular region occupied by the text will
              be  at the positioning point.  This option defaults
              to center.

       -fill color
              Color specifies a color to use for filling the text
              characters;  it  may have any of the forms accepted
              by Tk_GetColor.  If  this  option  isn't  specified
              then it defaults to black.

       -font fontName
              Specifies the font to use for the text item.  Font-
              Name  may  be  any  string  acceptable  to  Tk_Get-
              FontStruct.   If  this  option  isn't specified, it
              defaults to a system-dependent font.

       -justify how
              Specifies how to justify the text within its bound-
              ing  region.   How  must be one of the values left,
              right, or center.  This option will only matter  if
              the  text  is  displayed as multiple lines.  If the
              option is omitted, it defaults to left.

       -stipple bitmap
              Indicates that the text should be drawn in a  stip-
              pled  pattern  rather  than solid; bitmap specifies
              the stipple pattern to use, in  any  of  the  forms
              accepted  by  Tk_GetBitmap.   If bitmap is an empty
              string (the default) then the text is  drawn  in  a
              solid fashion.

       -tags tagList
              Specifies  a  set  of  tags  to  apply to the item.
              TagList consists of a  list  of  tag  names,  which
              replace  any  existing  tags for the item.  TagList
              may be an empty list.

       -text string
              String specifies the characters to be displayed  in
              the  text  item.   Newline  characters  cause  line
              breaks.  The characters in the  item  may  also  be
              changed with the insert and delete widget commands.
              This option defaults to an empty string.

       -width lineLength
              Specifies a maximum line length for  the  text,  in
              any  of the forms described in the COORDINATES sec-
              tion above.  If this option is zero  (the  default)
              the text is broken into lines only at newline char-
              acters.  However, if this option is  non-zero  then
              any  line  that  would be longer than lineLength is
              broken just before a space character  to  make  the
              line  shorter than lineLength;  the space character
              is treated as if it were a newline character.


WINDOW ITEMS
       Items of type window cause a particular window to be  dis-
       played  at  a  given position on the canvas.  Window items
       are created with widget commands of the following form:
              pathName create window x y ?option value option value ...?
       The arguments x and y specify the coordinates of  a  point
       used  to  position  the  window  on  the  display (see the
       -anchor option below for more information on  how  bitmaps
       are  displayed).   After  the coordinates there may be any
       number of option-value pairs, each of which  sets  one  of
       the  configuration  options  for  the  item.   These  same
       option-value pairs may be  used  in  itemconfigure  widget
       commands  to change the item's configuration.  The follow-
       ing options are supported for window items:

       -anchor anchorPos
              AnchorPos tells how to position the window relative
              to the positioning point for the item;  it may have
              any of the forms  accepted  by  Tk_GetAnchor.   For
              example,  if anchorPos is center then the window is
              centered on the point;  if anchorPos is n then  the
              window  will  be drawn so that its top center point
              is at the positioning point.  This option  defaults
              to center.

       -height pixels
              Specifies  the  height to assign to the item's win-
              dow.  Pixels may have any of the forms described in
              the  COORDINATES  section  above.   If  this option
              isn't specified, or if it is specified as an  empty
              string, then the window is given whatever height it
              requests internally.

       -tags tagList
              Specifies a set of  tags  to  apply  to  the  item.
              TagList  consists  of  a  list  of tag names, which
              replace any existing tags for  the  item.   TagList
              may be an empty list.

       -width pixels
              Specifies the width to assign to the item's window.
              Pixels may have any of the forms described  in  the
              COORDINATES  section  above.   If this option isn't
              specified, or  if  it  is  specified  as  an  empty
              string,  then the window is given whatever width it
              requests internally.

       -window pathName
              Specifies the window to associate with  this  item.
              The  window  specified by pathName must either be a
              child of the canvas  widget  or  a  child  of  some
              ancestor  of  the  canvas widget.  PathName may not
              refer to a top-level window.

       Note:  due to restrictions in the ways  that  windows  are
       managed,  it is not possible to draw other graphical items
       (such as lines and images) on top of window items.  A win-
       dow  item  always  obscures  any graphics that overlap it,
       regardless of their order in the display list.
APPLICATION-DEFINED ITEM TYPES
       It is possible for individual applications to  define  new
       item types for canvas widgets using C code.  See the docu-
       mentation for Tk_CreateItemType.


BINDINGS
       In the current implementation, new canvases are not  given
       any default behavior:  you'll have to execute explicit Tcl
       commands to give the canvas its behavior.


CREDITS
       Tk's canvas widget is a blatant ripoff of ideas from  Joel
       Bartlett's  ezd program.  Ezd provides structured graphics
       in a Scheme environment and preceded canvases by a year or
       two.   Its  simple  mechanisms  for  placing and animating
       graphical objects inspired the functions of canvases.


KEYWORDS
       canvas, widget
