pack append parent window options ?window options ...?
pack before sibling window options ?window options ...?
pack unpack window
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 Although this syntax continues to be supported for backward compatibility, it is obsolete and should not be used anymore.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 children 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 children 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 commands 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 process; the options argument following each window consists 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:
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_GeometryRequest. 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:
If the desired width or height for a parcel is larger than the corresponding dimension of the cavity, then the cavity'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 following options may be used to expand the window to partially or completely fill the parcel:
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 following options may be used to specify where the window should be positioned within its parcel:
The packer manages the mapped/unmapped state of all the packed children windows. It automatically maps the windows 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.