1pack(n)                      Tk Built-In Commands                      pack(n)
2
3
4
5______________________________________________________________________________
6

NAME

8       pack - Geometry manager that packs around edges of cavity
9

SYNOPSIS

11       pack option arg ?arg ...?
12_________________________________________________________________
13
14

DESCRIPTION

16       The  pack  command  is  used to communicate with the packer, a geometry
17       manager that arranges the children of a parent by packing them in order
18       around  the edges of the parent.  The pack command can have any of sev‐
19       eral forms, depending on the option argument:
20
21       pack slave ?slave ...? ?options?
22              If the first argument to pack is a window name (any value start‐
23              ing  with “.”), then the command is processed in the same way as
24              pack configure.
25
26       pack configure slave ?slave ...? ?options?
27              The arguments consist of the names of one or more slave  windows
28              followed  by  pairs  of arguments that specify how to manage the
29              slaves.  See THE PACKER ALGORITHM below for details on  how  the
30              options  are used by the packer.  The following options are sup‐
31              ported:
32
33              -after other
34                     Other must the name of another window.  Use its master as
35                     the  master  for  the  slaves, and insert the slaves just
36                     after other in the packing order.
37
38              -anchor anchor
39                     Anchor must be a valid anchor position such as n  or  sw;
40                     it  specifies where to position each slave in its parcel.
41                     Defaults to center.
42
43              -before other
44                     Other must the name of another window.  Use its master as
45                     the  master  for  the  slaves, and insert the slaves just
46                     before other in the packing order.
47
48              -expand boolean
49                     Specifies whether the slaves should be expanded  to  con‐
50                     sume  extra  space in their master.  Boolean may have any
51                     proper boolean value, such as 1 or no.  Defaults to 0.
52
53              -fill style
54                     If a slave's parcel is larger than its  requested  dimen‐
55                     sions,  this  option  may  be  used to stretch the slave.
56                     Style must have one of the following values:
57
58                     none   Give the slave its requested dimensions  plus  any
59                            internal  padding requested with -ipadx or -ipady.
60                            This is the default.
61
62                     x      Stretch the slave horizontally to fill the  entire
63                            width of its parcel (except leave external padding
64                            as specified by -padx).
65
66                     y      Stretch the slave vertically to  fill  the  entire
67                            height  of  its parcel (except leave external pad‐
68                            ding as specified by -pady).
69
70                     both   Stretch the slave  both  horizontally  and  verti‐
71                            cally.
72
73              -in other
74                     Insert  the  slave(s) at the end of the packing order for
75                     the master window given by other.
76
77              -ipadx amount
78                     Amount specifies how much horizontal internal padding  to
79                     leave  on  each  side  of the slave(s).  Amount must be a
80                     valid screen distance, such as 2 or .5c.  It defaults  to
81                     0.
82
83              -ipady amount
84                     Amount  specifies  how  much vertical internal padding to
85                     leave on each side of the slave(s).  Amount  defaults  to
86                     0.
87
88              -padx amount
89                     Amount  specifies how much horizontal external padding to
90                     leave on each side of the slave(s).  Amount may be a list
91                     of two values to specify padding for left and right sepa‐
92                     rately.  Amount defaults to 0.
93
94              -pady amount
95                     Amount specifies how much vertical  external  padding  to
96                     leave on each side of the slave(s).  Amount may be a list
97                     of two values to specify padding for top and bottom sepa‐
98                     rately.  Amount defaults to 0.
99
100              -side side
101                     Specifies  which  side of the master the slave(s) will be
102                     packed against.  Must be left,  right,  top,  or  bottom.
103                     Defaults to top.
104
105              If  no  -in,  -after or -before option is specified then each of
106              the slaves will be inserted at the end of the packing  list  for
107              its  parent unless it is already managed by the packer (in which
108              case it will be left where it is).  If one of these  options  is
109              specified  then all the slaves will be inserted at the specified
110              point.  If any of the slaves are already managed by the geometry
111              manager  then any unspecified options for them retain their pre‐
112              vious values rather than receiving default values.
113
114       pack forget slave ?slave ...?
115              Removes each of the slaves from the packing order for its master
116              and  unmaps their windows.  The slaves will no longer be managed
117              by the packer.
118
119       pack info slave
120              Returns a list whose  elements  are  the  current  configuration
121              state  of the slave given by slave in the same option-value form
122              that might be specified to pack configure.  The first  two  ele‐
123              ments  of  the list are “-in master” where master is the slave's
124              master.
125
126       pack propagate master ?boolean?
127              If boolean has a true boolean value such as 1 or on then  propa‐
128              gation  is  enabled for master, which must be a window name (see
129              GEOMETRY PROPAGATION below).  If boolean  has  a  false  boolean
130              value  then  propagation  is  disabled for master.  In either of
131              these cases an empty string is returned.  If boolean is  omitted
132              then  the command returns 0 or 1 to indicate whether propagation
133              is currently enabled for  master.   Propagation  is  enabled  by
134              default.
135
136       pack slaves master
137              Returns  a  list  of  all of the slaves in the packing order for
138              master.  The order of the slaves in the  list  is  the  same  as
139              their  order in the packing order.  If master has no slaves then
140              an empty string is returned.
141

THE PACKER ALGORITHM

143       For each master the packer maintains an ordered list of  slaves  called
144       the  packing  list.  The -in, -after, and -before configuration options
145       are used to specify the master for each slave and the slave's  position
146       in  the  packing  list.   If none of these options is given for a slave
147       then the slave is added to the end of the packing list for its parent.
148
149       The packer arranges the slaves for a master  by  scanning  the  packing
150       list in order.  At the time it processes each slave, a rectangular area
151       within the master is still unallocated.  This area is called  the  cav‐
152       ity;  for the first slave it is the entire area of the master.
153
154       For each slave the packer carries out the following steps:
155
156       [1]    The  packer  allocates  a rectangular parcel for the slave along
157              the side of the cavity given by the slave's  -side  option.   If
158              the  side  is  top or bottom then the width of the parcel is the
159              width of the cavity and its height is the  requested  height  of
160              the  slave  plus  the -ipady and -pady options.  For the left or
161              right side the height of the parcel is the height of the  cavity
162              and  the  width  is  the  requested  width of the slave plus the
163              -ipadx and -padx options.  The parcel may  be  enlarged  further
164              because of the -expand option (see EXPANSION below)
165
166       [2]    The  packer chooses the dimensions of the slave.  The width will
167              normally be the slave's requested width plus  twice  its  -ipadx
168              option  and  the  height  will normally be the slave's requested
169              height plus twice its -ipady  option.   However,  if  the  -fill
170              option  is  x or both then the width of the slave is expanded to
171              fill the width of the parcel, minus twice the -padx option.   If
172              the  -fill  option  is y or both then the height of the slave is
173              expanded to fill the width of the parcel, minus twice the  -pady
174              option.
175
176       [3]    The packer positions the slave over its parcel.  If the slave is
177              smaller than the parcel then the -anchor option determines where
178              in  the  parcel  the slave will be placed.  If -padx or -pady is
179              non-zero, then the given amount of external padding will  always
180              be left between the slave and the edges of the parcel.
181
182       Once  a  given  slave  has  been packed, the area of its parcel is sub‐
183       tracted from the cavity, leaving a smaller rectangular cavity  for  the
184       next  slave.   If  a  slave  does not use all of its parcel, the unused
185       space in the parcel will not be used by subsequent slaves.  If the cav‐
186       ity should become too small to meet the needs of a slave then the slave
187       will be given whatever space is left in  the  cavity.   If  the  cavity
188       shrinks  to  zero  size,  then all remaining slaves on the packing list
189       will be unmapped from the screen until the master window becomes  large
190       enough to hold them again.
191
192   EXPANSION
193       If a master window is so large that there will be extra space left over
194       after all of its slaves have been packed, then the extra space is  dis‐
195       tributed uniformly among all of the slaves for which the -expand option
196       is set.  Extra horizontal space is  distributed  among  the  expandable
197       slaves  whose  -side is left or right, and extra vertical space is dis‐
198       tributed among the expandable slaves whose -side is top or bottom.
199
200   GEOMETRY PROPAGATION
201       The packer normally computes how large a master must be to just exactly
202       meet  the  needs  of  its  slaves,  and it sets the requested width and
203       height of the master to these dimensions.  This causes geometry  infor‐
204       mation to propagate up through a window hierarchy to a top-level window
205       so that the entire sub-tree sizes itself to fit the needs of  the  leaf
206       windows.   However,  the pack propagate command may be used to turn off
207       propagation for one or more masters.  If propagation is  disabled  then
208       the  packer  will not set the requested width and height of the packer.
209       This may be useful if, for example, you wish for  a  master  window  to
210       have a fixed size that you specify.
211

RESTRICTIONS ON MASTER WINDOWS

213       The  master  for  each  slave  must  either  be the slave's parent (the
214       default) or a descendant of the slave's parent.   This  restriction  is
215       necessary  to  guarantee  that the slave can be placed over any part of
216       its master that is visible without danger of the slave being clipped by
217       its parent.
218

PACKING ORDER

220       If  the  master  for  a slave is not its parent then you must make sure
221       that the slave is higher in the stacking order than the master.  Other‐
222       wise  the  master  will  obscure the slave and it will appear as if the
223       slave has not been packed correctly.  The easiest way to make sure  the
224       slave  is  higher than the master is to create the master window first:
225       the most recently created window will be highest in the stacking order.
226       Or,  you  can  use  the raise and lower commands to change the stacking
227       order of either the master or the slave.
228

EXAMPLE

230              # Make the widgets
231              label .t -text "This widget is at the top"    -bg red
232              label .b -text "This widget is at the bottom" -bg green
233              label .l -text "Left\nHand\nSide"
234              label .r -text "Right\nHand\nSide"
235              text .mid
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
243

SEE ALSO

245       grid(n), place(n)
246
247

KEYWORDS

249       geometry manager, location, packer, parcel, propagation, size
250
251
252
253Tk                                    4.0                              pack(n)
Impressum