NAME
       canvas - Create and manipulate canvas widgets

SYNOPSIS
       canvas pathName ?options?

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

       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:-state
       Database Name:  state
       Database Class: State

              Modifies  the  default  state  of  the canvas where
              state may be set to one of:  normal,  disabled,  or
              hidden.  Individual  canvas  objects all have their
              own state option which  may  override  the  default
              state.   Many  options can take separate specifica-
              tions such that the appearance of the item  can  be
              different in different situations. The options that
              start with active control the appearence  when  the
              mouse pointer is over it, while the option starting
              with disabled  controls  the  appearence  when  the
              state is disabled.  Canvas items which are disabled
              will not react to canvas bindings.

       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.

       tagOrId may contain a logical expressions of tags by using
       operators:  '&&',  '||', '^' '!', and parenthezised subex-
       pressions.  For example:
                    .c find withtag {(a&&!b)|(!a&&b)}
       or equivalently:
                    .c find withtag {a^b}
       will find only those items with either "a"  or  "b"  tags,
       but not both.

       Some  widget  commands  only operate on a single item at a
       time;  if tagOrId is specified in a way that names  multi-
       ple  items, then the normal behavior is for the command to
       use the first (lowest) of these items in the display  list
       that is suitable for the command.  Exceptions are noted in
       the widget command 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
       letter 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.  In a similar fash-
       ion, line and polygon items support index for identifying,
       inserting  and  deleting  subsets  of  their  coordinates.
       Indices are used for commands such as inserting or  delet-
       ing  a range of characters or coordinates, 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.  Lines
       and  Polygons  don't  support the insertion cursor and the
       selection. Their indixes are supposed to be  even  always,
       because coordinates always appear in pairs.

       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. If  indexes  are  odd  for
                 lines  and  polygons, they will be automatically
                 decremented by one.  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.
                 For polygons, numbers less  than  0  or  greater
                 then  the  length of the coordinate list will be
                 adjusted by adding or  substracting  the  length
                 until the result is between zero and the length,
                 inclusive.

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

       insert    Refers to the character just  before  which  the
                 insertion  cursor  is  drawn  in  this item. Not
                 valid for lines and polygons.

       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  or  coordinate  at  the
                 point given by x and y, where x and y are speci-
                 fied in the coordinate 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  character  in  the line that is closest to
                 the given point.


DASH PATTERNS
       Many items support the notion of an dash pattern for  out-
       lines.

       The first possible syntax is a list of integers. Each ele-
       ment represents the number of pixels of  a  line  segment.
       Only the odd segments are drawn using the "outline" color.
       The other segments are drawn transparant.

       The second possible syntax is a character list  containing
       only  5 possible characters [.,-_ ]. The space can be used
       to enlarge the space between other line elements, and  can
       not  occur as the first posibion in the string. Some exam-
       ples:
           -dash .= -dash {2 4}
           -dash -     = -dash {6 4}
           -dash -.    = -dash {6 4 2 4}
           -dash -..   = -dash {6 4 2 4 2 4}
           -dash {. }  = -dash {2 8}
           -dash ,= -dash {4 4}

       The main difference of this syntax with  the  previous  is
       that it it shape-conserving. This means that all values in
       the dash list will be multiplied by the line width  before
       display. This assures that "." will always be displayed as
       a dot and "-" always as a  dash  regardless  of  the  line
       width.

       On  systems where only a limited set of dash patterns, the
       dash pattern will be displayed as the most close dash pat-
       tern  that  is available. For example, on Windows only the
       first 4 of the above examples are available.  The  last  2
       examples will be displayed identically as the first one.


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 path-
              Name (see Tk_ConfigureInfo for information  on  the
              format  of this list).  If option is specified with
              no value, then the command returns a list  describ-
              ing the one named option (this list will be identi-
              cal 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,  or  coordinates, in the range given by first
              and last, inclusive.  If some of the items given by
              tagOrId don't support indexing operations then they
              ignore dchars.  Text items interpret first and last
              as  indices  to a character, line and polygon items
              interpret them indices  to  a  coordinate  (an  x,y
              pair).  Indices are described in INDICES above.  If
              last is omitted, it defaults to first.   This  com-
              mand 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
              window  and  (b)  the item is the focus item within
              the canvas.  In most cases it is advisable to  fol-
              low 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.
              Text items interpret index as an index to a   char-
              acter,  line  and  polygon items interpret it as an
              index to a coordinate (an x,y  pair).   The  return
              value is guaranteed to lie between 0 and the number
              of characters, or  coordinates,  within  the  item,
              inclusive.   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 or coordinate, insertion then string
              is inserted into the item's text  just  before  the
              character,  or  coordinate,  whose index is before-
              This.  Text items interpret beforethis as an  index
              to  a   character, line and polygon items interpret
              it as an index to a coordinate (an x,y pair).   For
              lines and polygons the string must be a valid coor-
              dinate sequence.  See INDICES above for information
              about  the forms allowed for beforeThis.  This com-
              mand 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 ?gain?.
                     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 gain times
                     the  difference  in  coordinates, where gain
                     defaults to 10.  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  hori-
              zontal position of the information displayed in the
              canvas's window.  It can take any of the  following
              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, text, line and
       polygon items provide this support.  For lines  and  poly-
       gons the indexing facility is used to manipulate the coor-
       dinates of the item.


COMMON ITEM OPTIONS
       Many items share a common set of options.   These  options
       are  explained  here,  and then referred to be each widget
       type for brevity.


       -dash pattern

       -activedash pattern

       -disableddash pattern
              This option specifies dash patterns for the  normal
              state,  the active state, and the disabled state of
              an arc item.  pattern may have  any  of  the  forms
              accepted  by  Tk_GetDash.   If the dash options are
              omitted then the default is a solid  outline.   See
              "DASH PATTERNS" for more information.

       -dashoffset offset
              The  starting  offset  into the pattern provided by
              the -dash option.  -dashoffset is ignored if  there
              is no -dash pattern.

       -fill color

       -activefill color

       -disabledfill color
              Specifies the color to be used to fill item's area.
              in its normal, active, and disabled  states,  Color
              may  have any of the forms accepted by Tk_GetColor.
              If color is an empty  string  (the  default),  then
              then  the  item  will  not be filled.  For the line
              item, it specifies the color  of  the  line  drawn.
              For  the  text  item,  it  specifies the foreground
              color of the text.

       -outline color

       -activeoutline color

       -disabledoutline color
              This option specifies the color that should be used
              to  draw  the  outline  of  the item in its normal,
              active and disabled states.  Color 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 item.

       -offset offset
              Specifies the offset of stipples.  The offset value
              can  be  of the form x,y or side, where side can be
              n, ne, e, se, s, sw, w, nw, or center. In the first
              case  the  origin  is the origin of the toplevel of
              the current window.  For the canvas itself and can-
              vas  objects  the  origin is the canvas origin, but
              putting # in front of the coordinate pair indicates
              using  the  toplevel  origin  in  stead. For canvas
              objects, the -offset option is used  for  stippling
              as well.  For the line and polygon canvas items you
              can also specify an index as argument,  which  con-
              nects  the  stipple origin to one of the coordinate
              points of the line/polygon.

       -outlinestipple bitmap

       -activeoutlinestipple bitmap

       -disabledoutlinestipple bitmap
              This option specifies stipple patterns that  should
              be used to draw the outline of the item in its nor-
              mal, active and disabled  states.   Indicates  that
              the  outline  for  the  item should be drawn with a
              stipple pattern; bitmap specifies the stipple  pat-
              tern  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.

       -stipple bitmap

       -activestipple bitmap

       -disabledstipple bitmap
              This  option specifies stipple patterns that should
              be used to fill the the item in its normal,  active
              and  disabled states.  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.  For the text item,
              it affects the actual text.

       -state state
              This allows an item to override the canvas widget's
              global state option.  It  takes  the  same  values:
              normal, disabled or hidden.

       -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

       -activewidth outlineWidth

       -disabledwidth outlineWidth
              Specifies the width of  the  outline  to  be  drawn
              around the item's region, in its normal, active and
              disabled states.  outlineWidth may be 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.  This
              option defaults to 1.0.  For  arcs,  wide  outlines
              will  be  drawn  centered on the edges of the arc's
              region.


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 standard options are supported by arcs:
              -dash
              -activedash
              -disableddash
              -dashoffset
              -fill
              -activefill
              -disabledfill
              -offset
              -outline
              -activeoutline
              -disabledoutline
              -outlinestipple
              -activeoutlinestipple
              -disabledoutlinestipple
              -stipple
              -activestipple
              -disabledstipple
              -state
              -tags
              -width
              -activewidth
              -disabledwidth
       The following extra 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.

       -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.

       -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.


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 following standard options are supported by bitmaps:
              -state
              -tags
       The following extra 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

       -activebackground bitmap

       -disabledbackground bitmap
              Specifies the color to use for each of the bitmap's
              '0' valued pixels in its normal,  active  and  dis-
              abled  states.   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

       -activebitmap bitmap

       -disabledbitmap bitmap
              Specifies the bitmaps to display in the item in its
              normal,  active  and  disabled  states.  Bitmap may
              have any of the forms accepted by Tk_GetBitmap.

       -foreground color

       -activeforeground bitmap

       -disabledforeground bitmap
              Specifies the color to use for each of the bitmap's
              '1'  valued  pixels  in its normal, active and dis-
              abled states.  Color may  have  any  of  the  forms
              accepted by Tk_GetColor and defaults to black.
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 standard options are supported by images:
              -state
              -tags
       The following extra 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

       -activeimage name

       -disabledimage name
              Specifies the name of the images to display in  the
              item  in  is  normal,  active  and disabled states.
              This image must have been created  previously  with
              the image create command.


LINE ITEMS
       Items  of  type  line appear on the display as one or more
       connected line segments or  curves.   Line  items  support
       coordinate  indexing  operations  using  the canvas widget
       commands: dchars, index, insert.  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 following standard options are supported by lines:
              -dash
              -activedash
              -disableddash
              -dashoffset
              -fill
              -activefill
              -disabledfill
              -stipple
              -activestipple
              -disabledstipple
              -state
              -tags
              -width
              -activewidth
              -disabledwidth
       The following extra 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.

       -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.


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 standard options are supported by ovals:
              -dash
              -activedash
              -disableddash
              -dashoffset
              -fill
              -activefill
              -disabledfill
              -offset
              -outline
              -activeoutline
              -disabledoutline
              -outlinestipple
              -activeoutlinestipple
              -disabledoutlinestipple
              -stipple
              -activestipple
              -disabledstipple
              -state
              -tags
              -width
              -activewidth
              -disabledwidth


POLYGON ITEMS
       Items of type polygon appear as polygonal or curved filled
       regions  on the display.  Polygon items support coordinate
       indexing operations  using  the  canvas  widget  commands:
       dchars,  index,  insert.  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 polygon.  The first
       point should not be repeated as  the  last  to  close  the
       shape;  Tk  will automatically close the periphery between
       the first and last points.  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 following standard options are supported by polygons:
              -dash
              -activedash
              -disableddash
              -dashoffset
              -fill
              -activefill
              -disabledfill
              -offset
              -outline
              -activeoutline
              -disabledoutline
              -outlinestipple
              -activeoutlinestipple
              -disabledoutlinestipple
              -stipple
              -activestipple
              -disabledstipple
              -state
              -tags
              -width
              -activewidth
              -disabledwidth
       The following extra options are supported for polygons:

       -joinstyle style
              Specifies the ways in which joints are to be  drawn
              at the vertices of the outline.  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.
       -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.

       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 following standard options are  supported  by  rectan-
       gles:
              -dash
              -activedash
              -disableddash
              -dashoffset
              -fill
              -activefill
              -disabledfill
              -offset
              -outline
              -activeoutline
              -disabledoutline
              -outlinestipple
              -activeoutlinestipple
              -disabledoutlinestipple
              -stipple
              -activestipple
              -disabledstipple
              -state
              -tags
              -width
              -activewidth
              -disabledwidth


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  standard  options  are  supported  by text
       items:
              -fill
              -activefill
              -disabledfill
              -stipple
              -activestipple
              -disabledstipple
              -state
              -tags
       The following extra 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.
       -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.

       -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 following standard options  are  supported  by  window
       items:
              -state
              -tags
       The  following  extra  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.

       -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
