1pack(n)                      Tk Built-In Commands                      pack(n)
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NAME

8       pack - Geometry manager that packs around edges of cavity
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SYNOPSIS

11       pack option arg ?arg ...?
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DESCRIPTION

15       The  pack  command  is  used to communicate with the packer, a geometry
16       manager that arranges the children of a parent by packing them in order
17       around  the edges of the parent.  The pack command can have any of sev‐
18       eral forms, depending on the option argument:
19
20       pack slave ?slave ...? ?options?
21              If the first argument to pack is a window name (any value start‐
22              ing  with “.”), then the command is processed in the same way as
23              pack configure.
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25       pack configure slave ?slave ...? ?options?
26              The arguments consist of the names of one or more slave  windows
27              followed  by  pairs  of arguments that specify how to manage the
28              slaves.  See THE PACKER ALGORITHM below for details on  how  the
29              options  are used by the packer.  The following options are sup‐
30              ported:
31
32              -after other
33                     Other must the name of another window.  Use its master as
34                     the  master  for  the  slaves, and insert the slaves just
35                     after other in the packing order.
36
37              -anchor anchor
38                     Anchor must be a valid anchor position such as n  or  sw;
39                     it  specifies where to position each slave in its parcel.
40                     Defaults to center.
41
42              -before other
43                     Other must the name of another window.  Use its master as
44                     the  master  for  the  slaves, and insert the slaves just
45                     before other in the packing order.
46
47              -expand boolean
48                     Specifies whether the slaves should be expanded  to  con‐
49                     sume  extra  space in their master.  Boolean may have any
50                     proper boolean value, such as 1 or no.  Defaults to 0.
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52              -fill style
53                     If a slave's parcel is larger than its  requested  dimen‐
54                     sions,  this  option  may  be  used to stretch the slave.
55                     Style must have one of the following values:
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57                     none   Give the slave its requested dimensions  plus  any
58                            internal  padding requested with -ipadx or -ipady.
59                            This is the default.
60
61                     x      Stretch the slave horizontally to fill the  entire
62                            width of its parcel (except leave external padding
63                            as specified by -padx).
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65                     y      Stretch the slave vertically to  fill  the  entire
66                            height  of  its parcel (except leave external pad‐
67                            ding as specified by -pady).
68
69                     both   Stretch the slave  both  horizontally  and  verti‐
70                            cally.
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72              -in other
73                     Insert  the  slave(s) at the end of the packing order for
74                     the master window given by other.
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76              -ipadx amount
77                     Amount specifies how much horizontal internal padding  to
78                     leave  on  each  side  of the slave(s).  Amount must be a
79                     valid screen distance, such as 2 or .5c.  It defaults  to
80                     0.
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82              -ipady amount
83                     Amount  specifies  how  much vertical internal padding to
84                     leave on each side of the slave(s).  Amount  defaults  to
85                     0.
86
87              -padx amount
88                     Amount  specifies how much horizontal external padding to
89                     leave on each side of the slave(s).  Amount may be a list
90                     of two values to specify padding for left and right sepa‐
91                     rately.  Amount defaults to 0.
92
93              -pady amount
94                     Amount specifies how much vertical  external  padding  to
95                     leave on each side of the slave(s).  Amount may be a list
96                     of two values to specify padding for top and bottom sepa‐
97                     rately.  Amount defaults to 0.
98
99              -side side
100                     Specifies  which  side of the master the slave(s) will be
101                     packed against.  Must be left,  right,  top,  or  bottom.
102                     Defaults to top.
103
104              If  no  -in,  -after or -before option is specified then each of
105              the slaves will be inserted at the end of the packing  list  for
106              its  parent unless it is already managed by the packer (in which
107              case it will be left where it is).  If one of these  options  is
108              specified  then all the slaves will be inserted at the specified
109              point.  If any of the slaves are already managed by the geometry
110              manager  then any unspecified options for them retain their pre‐
111              vious values rather than receiving default values.
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113       pack forget slave ?slave ...?
114              Removes each of the slaves from the packing order for its master
115              and  unmaps their windows.  The slaves will no longer be managed
116              by the packer.
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118       pack info slave
119              Returns a list whose  elements  are  the  current  configuration
120              state  of the slave given by slave in the same option-value form
121              that might be specified to pack configure.  The first  two  ele‐
122              ments  of  the list are “-in master” where master is the slave's
123              master.
124
125       pack propagate master ?boolean?
126              If boolean has a true boolean value such as 1 or on then  propa‐
127              gation  is  enabled for master, which must be a window name (see
128              GEOMETRY PROPAGATION below).  If boolean  has  a  false  boolean
129              value  then  propagation  is  disabled for master.  In either of
130              these cases an empty string is returned.  If boolean is  omitted
131              then  the command returns 0 or 1 to indicate whether propagation
132              is currently enabled for  master.   Propagation  is  enabled  by
133              default.
134
135       pack slaves master
136              Returns  a  list  of  all of the slaves in the packing order for
137              master.  The order of the slaves in the  list  is  the  same  as
138              their  order in the packing order.  If master has no slaves then
139              an empty string is returned.
140

THE PACKER ALGORITHM

142       For each master the packer maintains an ordered list of  slaves  called
143       the  packing  list.  The -in, -after, and -before configuration options
144       are used to specify the master for each slave and the slave's  position
145       in  the  packing  list.   If none of these options is given for a slave
146       then the slave is added to the end of the packing list for its parent.
147
148       The packer arranges the slaves for a master  by  scanning  the  packing
149       list in order.  At the time it processes each slave, a rectangular area
150       within the master is still unallocated.  This area is called  the  cav‐
151       ity;  for the first slave it is the entire area of the master.
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153       For each slave the packer carries out the following steps:
154
155       [1]    The  packer  allocates  a rectangular parcel for the slave along
156              the side of the cavity given by the slave's  -side  option.   If
157              the  side  is  top or bottom then the width of the parcel is the
158              width of the cavity and its height is the  requested  height  of
159              the  slave  plus  the -ipady and -pady options.  For the left or
160              right side the height of the parcel is the height of the  cavity
161              and  the  width  is  the  requested  width of the slave plus the
162              -ipadx and -padx options.  The parcel may  be  enlarged  further
163              because of the -expand option (see EXPANSION below)
164
165       [2]    The  packer chooses the dimensions of the slave.  The width will
166              normally be the slave's requested width plus  twice  its  -ipadx
167              option  and  the  height  will normally be the slave's requested
168              height plus twice its -ipady  option.   However,  if  the  -fill
169              option  is  x or both then the width of the slave is expanded to
170              fill the width of the parcel, minus twice the -padx option.   If
171              the  -fill  option  is y or both then the height of the slave is
172              expanded to fill the width of the parcel, minus twice the  -pady
173              option.
174
175       [3]    The packer positions the slave over its parcel.  If the slave is
176              smaller than the parcel then the -anchor option determines where
177              in  the  parcel  the slave will be placed.  If -padx or -pady is
178              non-zero, then the given amount of external padding will  always
179              be left between the slave and the edges of the parcel.
180
181       Once  a  given  slave  has  been packed, the area of its parcel is sub‐
182       tracted from the cavity, leaving a smaller rectangular cavity  for  the
183       next  slave.   If  a  slave  does not use all of its parcel, the unused
184       space in the parcel will not be used by subsequent slaves.  If the cav‐
185       ity should become too small to meet the needs of a slave then the slave
186       will be given whatever space is left in  the  cavity.   If  the  cavity
187       shrinks  to  zero  size,  then all remaining slaves on the packing list
188       will be unmapped from the screen until the master window becomes  large
189       enough to hold them again.
190
191   EXPANSION
192       If a master window is so large that there will be extra space left over
193       after all of its slaves have been packed, then the extra space is  dis‐
194       tributed uniformly among all of the slaves for which the -expand option
195       is set.  Extra horizontal space is  distributed  among  the  expandable
196       slaves  whose  -side is left or right, and extra vertical space is dis‐
197       tributed among the expandable slaves whose -side is top or bottom.
198
199   GEOMETRY PROPAGATION
200       The packer normally computes how large a master must be to just exactly
201       meet  the  needs  of  its  slaves,  and it sets the requested width and
202       height of the master to these dimensions.  This causes geometry  infor‐
203       mation to propagate up through a window hierarchy to a top-level window
204       so that the entire sub-tree sizes itself to fit the needs of  the  leaf
205       windows.   However,  the pack propagate command may be used to turn off
206       propagation for one or more masters.  If propagation is  disabled  then
207       the  packer  will not set the requested width and height of the packer.
208       This may be useful if, for example, you wish for  a  master  window  to
209       have a fixed size that you specify.
210

RESTRICTIONS ON MASTER WINDOWS

212       The  master  for  each  slave  must  either  be the slave's parent (the
213       default) or a descendant of the slave's parent.   This  restriction  is
214       necessary  to  guarantee  that the slave can be placed over any part of
215       its master that is visible without danger of the slave being clipped by
216       its parent.
217

PACKING ORDER

219       If  the  master  for  a slave is not its parent then you must make sure
220       that the slave is higher in the stacking order than the master.  Other‐
221       wise  the  master  will  obscure the slave and it will appear as if the
222       slave has not been packed correctly.  The easiest way to make sure  the
223       slave  is  higher than the master is to create the master window first:
224       the most recently created window will be highest in the stacking order.
225       Or,  you  can  use  the raise and lower commands to change the stacking
226       order of either the master or the slave.
227

EXAMPLE

229              # Make the widgets
230              label .t -text "This widget is at the top"    -bg red
231              label .b -text "This widget is at the bottom" -bg green
232              label .l -text "Left\nHand\nSide"
233              label .r -text "Right\nHand\nSide"
234              text .mid
235              .mid insert end "This layout is like Java's BorderLayout"
236              # Lay them out
237              pack .t   -side top    -fill x
238              pack .b   -side bottom -fill x
239              pack .l   -side left   -fill y
240              pack .r   -side right  -fill y
241              pack .mid -expand 1    -fill both
242

SEE ALSO

244       grid(n), place(n)
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KEYWORDS

247       geometry manager, location, packer, parcel, propagation, size
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251Tk                                    4.0                              pack(n)
Impressum