1pack(n) Tk Built-In Commands pack(n)
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8 pack - Geometry manager that packs around edges of cavity
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11 pack option arg ?arg ...?
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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 pack window ?window ...? ?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.
24 pack configure window ?window ...? ?options?
26 The arguments consist of the names of one or more content win‐
27 dows followed by pairs of arguments that specify how to manage
28 the content. See THE PACKER ALGORITHM below for details on how
29 the options are used by the packer. The following options are
30 supported:
31 -after other
33 Other must the name of another window. Use its container
34 as the container for the content, and insert the content
35 just after other in the packing order.
36 -anchor anchor
38 Anchor must be a valid anchor position such as n or sw;
39 it specifies where to position each content in its par‐
40 cel. Defaults to center.
41 -before other
43 Other must the name of another window. Use its container
44 as the container for the content, and insert the content
45 just before other in the packing order.
46 -expand boolean
48 Specifies whether the content should be expanded to con‐
49 sume extra space in their container. Boolean may have
50 any proper boolean value, such as 1 or no. Defaults to
51 0.
52 -fill style
54 If a content's parcel is larger than its requested dimen‐
55 sions, this option may be used to stretch the content.
56 Style must have one of the following values:
57 none Give the content its requested dimensions plus any
59 internal padding requested with -ipadx or -ipady.
60 This is the default.
61 x Stretch the content horizontally to fill the en‐
63 tire width of its parcel (except leave external
64 padding as specified by -padx).
65 y Stretch the content vertically to fill the entire
67 height of its parcel (except leave external pad‐
68 ding as specified by -pady).
69 both Stretch the content both horizontally and verti‐
71 cally.
72 -in container
74 Insert the window at the end of the packing order for the
75 container window given by container.
76 -ipadx amount
78 Amount specifies how much horizontal internal padding to
79 leave on each side of the content. Amount must be a
80 valid screen distance, such as 2 or .5c. It defaults to
81 0.
82 -ipady amount
84 Amount specifies how much vertical internal padding to
85 leave on each side of the content. Amount defaults to
86 0.
87 -padx amount
89 Amount specifies how much horizontal external padding to
90 leave on each side of the content. Amount may be a list
91 of two values to specify padding for left and right sepa‐
92 rately. Amount defaults to 0.
93 -pady amount
95 Amount specifies how much vertical external padding to
96 leave on each side of the content. Amount may be a list
97 of two values to specify padding for top and bottom sepa‐
98 rately. Amount defaults to 0.
99 -side side
101 Specifies which side of the container the content will be
102 packed against. Must be left, right, top, or bottom.
103 Defaults to top.
104 If no -in, -after or -before option is specified then each of
106 the content 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 content will be inserted at the specified
110 point. If any of the content are already managed by the geome‐
111 try manager then any unspecified options for them retain their
112 previous values rather than receiving default values.
113 pack forget window ?window ...?
115 Removes each of the windows from the packing order for its con‐
116 tainer and unmaps their windows. The content will no longer be
117 managed by the packer.
118 pack info window
120 Returns a list whose elements are the current configuration
121 state of the window given by window in the same option-value
122 form that might be specified to pack configure. The first two
123 elements of the list are “-in container” where container is the
124 window's container.
125 pack propagate container ?boolean?
127 If boolean has a true boolean value such as 1 or on then propa‐
128 gation is enabled for container, which must be a window name
129 (see GEOMETRY PROPAGATION below). If boolean has a false bool‐
130 ean value then propagation is disabled for container. In either
131 of these cases an empty string is returned. If boolean is omit‐
132 ted then the command returns 0 or 1 to indicate whether propaga‐
133 tion is currently enabled for container. Propagation is enabled
134 by default.
135 pack slaves window
137 Returns a list of all of the content windows in the packing or‐
138 der for window. The order of the content windows in the list is
139 the same as their order in the packing order. If window has no
140 content then an empty string is returned. │
141 pack content window │
143 Synonym for pack slaves window.
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146 For each container the packer maintains an ordered list of content win‐
147 dows called the packing list. The -in, -after, and -before configura‐
148 tion options are used to specify the container for each content and the
149 content's position in the packing list. If none of these options is
150 given for a content then the content is added to the end of the packing
151 list for its parent.
152 The packer arranges the content windows for a container by scanning the
154 packing list in order. At the time it processes each content, a rec‐
155 tangular area within the container is still unallocated. This area is
156 called the cavity; for the first content it is the entire area of the
157 container.
158 For each content the packer carries out the following steps:
160 [1] The packer allocates a rectangular parcel for the content along
162 the side of the cavity given by the content's -side option. If
163 the side is top or bottom then the width of the parcel is the
164 width of the cavity and its height is the requested height of
165 the content plus the -ipady and -pady options. For the left or
166 right side the height of the parcel is the height of the cavity
167 and the width is the requested width of the content plus the
168 -ipadx and -padx options. The parcel may be enlarged further
169 because of the -expand option (see EXPANSION below)
170 [2] The packer chooses the dimensions of the content. The width
172 will normally be the content's requested width plus twice its
173 -ipadx option and the height will normally be the content's re‐
174 quested height plus twice its -ipady option. However, if the
175 -fill option is x or both then the width of the content is ex‐
176 panded to fill the width of the parcel, minus twice the -padx
177 option. If the -fill option is y or both then the height of the
178 content is expanded to fill the width of the parcel, minus twice
179 the -pady option.
180 [3] The packer positions the content over its parcel. If the con‐
182 tent is smaller than the parcel then the -anchor option deter‐
183 mines where in the parcel the content will be placed. If -padx
184 or -pady is non-zero, then the given amount of external padding
185 will always be left between the content and the edges of the
186 parcel.
187 Once a given content has been packed, the area of its parcel is sub‐
189 tracted from the cavity, leaving a smaller rectangular cavity for the
190 next content. If a content does not use all of its parcel, the unused
191 space in the parcel will not be used by subsequent content. If the
192 cavity should become too small to meet the needs of a content then the
193 content will be given whatever space is left in the cavity. If the
194 cavity shrinks to zero size, then all remaining content on the packing
195 list will be unmapped from the screen until the container window be‐
196 comes large enough to hold them again.
197 EXPANSION
199 If a container window is so large that there will be extra space left
200 over after all of its content have been packed, then the extra space is
201 distributed uniformly among all of the content for which the -expand
202 option is set. Extra horizontal space is distributed among the expand‐
203 able content whose -side is left or right, and extra vertical space is
204 distributed among the expandable content whose -side is top or bottom.
205 GEOMETRY PROPAGATION
207 The packer normally computes how large a container must be to just ex‐
208 actly meet the needs of its content, and it sets the requested width
209 and height of the container to these dimensions. This causes geometry
210 information to propagate up through a window hierarchy to a top-level
211 window so that the entire sub-tree sizes itself to fit the needs of the
212 leaf windows. However, the pack propagate command may be used to turn
213 off propagation for one or more containers. If propagation is disabled
214 then the packer will not set the requested width and height of the
215 packer. This may be useful if, for example, you wish for a container
216 window to have a fixed size that you specify.
217
219 The container for each content must either be the content's parent (the
220 default) or a descendant of the content's parent. This restriction is
221 necessary to guarantee that the content can be placed over any part of
222 its container that is visible without danger of the content being
223 clipped by its parent.
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226 If the container for a content is not its parent then you must make
227 sure that the content is higher in the stacking order than the con‐
228 tainer. Otherwise the container will obscure the content and it will
229 appear as if the content has not been packed correctly. The easiest
230 way to make sure the content is higher than the container is to create
231 the container window first: the most recently created window will be
232 highest in the stacking order. Or, you can use the raise and lower
233 commands to change the stacking order of either the container or the
234 content.
235
237 # Make the widgets
238 label .t -text "This widget is at the top" -bg red
239 label .b -text "This widget is at the bottom" -bg green
240 label .l -text "Left\nHand\nSide"
241 label .r -text "Right\nHand\nSide"
242 text .mid
243 .mid insert end "This layout is like Java's BorderLayout"
244 # Lay them out
245 pack .t -side top -fill x
246 pack .b -side bottom -fill x
247 pack .l -side left -fill y
248 pack .r -side right -fill y
249 pack .mid -expand 1 -fill both
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252 grid(n), place(n)
253
255 geometry manager, location, packer, parcel, propagation, size
256Tk 4.0 pack(n)