pack-old(n) Tk Built-In Commands pack-old(n)_________________________________________________________________NAME
pack - Obsolete syntax for packer geometry manager
SYNOPSIS
pack after sibling window options ?window options ...?
pack append parent window options ?window options ...?
pack before sibling window options ?window options ...?
pack unpack window
_________________________________________________________________DESCRIPTION
Note: this manual entry describes the syntax for the pack
command as it existed before Tk version 3.3. Although
this syntax continues to be supported for backward compat-
ibility, it is obsolete and should not be used anymore.
At some point in the future it may cease to be supported.
The packer is a geometry manager that arranges the chil-
dren of a parent by packing them in order around the edges
of the parent. The first child is placed against one side
of the window, occupying the entire span of the window
along that side. This reduces the space remaining for
other children as if the side had been moved in by the
size of the first child. Then the next child is placed
against one side of the remaining cavity, and so on until
all children have been placed or there is no space left in
the cavity.
The before, after, and append forms of the pack command
are used to insert one or more children into the packing
order for their parent. The before form inserts the chil-
dren before window sibling in the order; all of the other
windows must be siblings of sibling. The after form
inserts the windows after sibling, and the append form
appends one or more windows to the end of the packing
order for parent. If a window named in any of these com-
mands is already packed in its parent, it is removed from
its current position in the packing order and repositioned
as indicated by the command. All of these commands return
an empty string as result.
The unpack form of the pack command removes window from
the packing order of its parent and unmaps it. After the
execution of this command the packer will no longer manage
window's geometry.
The placement of each child is actually a four-step pro-
cess; the options argument following each window consists
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pack-old(n) Tk Built-In Commands pack-old(n)
of a list of one or more fields that govern the placement
of that window. In the discussion below, the term cavity
refers to the space left in a parent when a particular
child is placed (i.e. all the space that wasn't claimed by
earlier children in the packing order). The term parcel
refers to the space allocated to a particular child; this
is not necessarily the same as the child window's final
geometry.
The first step in placing a child is to determine which
side of the cavity it will lie against. Any one of the
following options may be used to specify a side:
top Position the child's parcel against the top of the
cavity, occupying the full width of the cavity.
bottom Position the child's parcel against the bottom of
the cavity, occupying the full width of the cavity.
left Position the child's parcel against the left side
of the cavity, occupying the full height of the
cavity.
right Position the child's parcel against the right side
of the cavity, occupying the full height of the
cavity.
At most one of these options should be specified for any
given window. If no side is specified, then the default
is top.
The second step is to decide on a parcel for the child.
For top and bottom windows, the desired parcel width is
normally the cavity width and the desired parcel height is
the window's requested height, as passed to Tk_GeometryRe-
quest. For left and right windows, the desired parcel
height is normally the cavity height and the desired width
is the window's requested width. However, extra space may
be requested for the window using any of the following
options:
padx num Add num pixels to the window's requested width
before computing the parcel size as described
above.
pady num Add num pixels to the window's requested
height before computing the parcel size as
described above.
expand This option requests that the window's parcel
absorb any extra space left over in the par-
ent's cavity after packing all the children.
The amount of space left over depends on the
sizes requested by the other children, and may
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pack-old(n) Tk Built-In Commands pack-old(n)
be zero. If several windows have all speci-
fied expand then the extra width will be
divided equally among all the left and right
windows that specified expand and the extra
height will be divided equally among all the
top and bottom windows that specified expand.
If the desired width or height for a parcel is larger than
the corresponding dimension of the cavity, then the cav-
ity's dimension is used instead.
The third step in placing the window is to decide on the
window's width and height. The default is for the window
to receive either its requested width and height or the
those of the parcel, whichever is smaller. If the parcel
is larger than the window's requested size, then the fol-
lowing options may be used to expand the window to par-
tially or completely fill the parcel:
fill Set the window's size to equal the parcel size.
fillx Increase the window's width to equal the parcel's
width, but retain the window's requested height.
filly Increase the window's height to equal the parcel's
height, but retain the window's requested width.
The last step is to decide the window's location within
its parcel. If the window's size equals the parcel's
size, then the window simply fills the entire parcel. If
the parcel is larger than the window, then one of the fol-
lowing options may be used to specify where the window
should be positioned within its parcel:
frame center Center the window in its parcel. This is
the default if no framing option is speci-
fied.
frame n Position the window with its top edge cen-
tered on the top edge of the parcel.
frame ne Position the window with its upper-right
corner at the upper-right corner of the
parcel.
frame e Position the window with its right edge
centered on the right edge of the parcel.
frame se Position the window with its lower-right
corner at the lower-right corner of the
parcel.
frame s Position the window with its bottom edge
centered on the bottom edge of the parcel.
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pack-old(n) Tk Built-In Commands pack-old(n)
frame sw Position the window with its lower-left
corner at the lower-left corner of the par-
cel.
frame w Position the window with its left edge cen-
tered on the left edge of the parcel.
frame nw Position the window with its upper-left
corner at the upper-left corner of the par-
cel.
The packer manages the mapped/unmapped state of all the
packed children windows. It automatically maps the win-
dows when it packs them, and it unmaps any windows for
which there was no space left in the cavity.
The packer makes geometry requests on behalf of the parent
windows it manages. For each parent window it requests a
size large enough to accommodate all the options specified
by all the packed children, such that zero space would be
leftover for expand options.
KEYWORDS
geometry manager, location, packer, parcel, size
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