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pack

Blib R support for connected components


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1. pack.3.man

Manpage of LIBPACK

LIBPACK

Section: C Library Functions (3)
Updated: 01 MAY 2002
Index Return to Main Contents
 

NAME

libpack - support for connected components  

SYNOPSIS


#include <graphviz/pack.h>

typedef enum { l_clust, l_node, l_graph} pack_mode;

typedef struct {
    unsigned int margin;
    boolean      doSplines;
    pack_mode    mode;
    boolean*     fixed;
} pack_info;

point*     putGraphs (int, Agraph_t**, Agraph_t*, pack_info*);
int        packGraphs (int, Agraph_t**, Agraph_t*, pack_info*);
int        packSubgraphs (int, Agraph_t**, Agraph_t*, pack_info*);

pack_mode  getPackMode (Agraph_t*, pack_mode dflt);
int        getPack (Agraph_t*, int, int);

int        isConnected (Agraph_t*);
Agraph_t** ccomps (Agraph_t*, int*, char*);
Agraph_t** pccomps (Agraph_t*, int*, char*, boolean*);
int        nodeInduce (Agraph_t*);


 

DESCRIPTION

libpack supports the use of connected components in the context of laying out graphs using other graphviz libraries. One set of functions can be used to take a single graph and break it apart into connected components. A complementary set of functions takes a collection of graphs (not necessarily components of a single graph) which have been laid out separately, and packs them together moderately tightly. The packing is done using the polyomino algorithm of K. Freivalds et al.

As this library is meant to be used with libcommon, it relies on the Agraphinfo_t, Agnodeinfo_t and Agedgeinfo_t used in that library. The specific dependencies are given below in the function descriptions.

 

Creating components

 

Agraph_t** ccomps (Agraph_t* g, int* cnt, char* pfx)

The function ccomps takes a graph g and returns an array of pointers to subgraphs of g which are its connected components. cnt is set to the number of components. If pfx is non-NULL, it is used as a prefix for the names of the subgraphs; otherwise, the string ``_cc_'' is used. Note that the subgraphs only contain the relevant nodes, not any corresponding edges. Depending on the use, this allows the caller to retrieve edge information from the root graph.

The array returned is obtained from malloc and must be freed by the caller. The function relies on the mark field in Agnodeinfo_t.

 

Agraph_t** pccomps (Agraph_t* g, int* cnt, char* pfx, boolean* pinned)

This is identical to ccomps except that is puts all pinned nodes in the first component returned. In addition, if pinned is non-NULL, it is set to true if pinned nodes are found and false otherwise.

 

int nodeInduce (Agraph_t* g)

This function takes a subgraph g and finds all edges in its root graph both of whose endpoints are in g. It returns the number of such edges and, if this edge is not already in the subgraph, it is added.

 

int isConnected (Agraph_t* g)

This function returns non-zero if the graph g is connected.

 

Packing components

 

point* putGraphs (int ng, Agraph_t** gs, Agraph_t* root, pack_info ip)

putGraphs packs together a collection of laid out graphs into a single layout which avoids any overlap. It takes as input ng graphs gs. For each graph, it is assumed that all the nodes have been positioned using pos, and that the xsize and ysize fields have been set. The packing is done using the polyomino-based algorithm of Freivalds et al. This allows for a fairly tight packing, in which a convex part of one graph might be inserted into the concave part of another.

If root is non-NULL, it is taken as the root graph of the subgraphs gs and is used to find the edges. Otherwise, putGraphs uses the edges found in each graph gs[i].

The granularity of the polyominoes used depends on the value of ip->mode. If this is l_node, a polyomino is constructed to approximate the nodes and edges. If this is l_clust, the polyomino treats top-level clusters as single rectangles, unioned with the polyominoes for the remaining nodes and edges. If the value is l_graph, the polyomino for a graph is a single rectangle corresponding to the bounding box of the graph.

If ip->doSplines is true, the function uses the spline information in the spl field of an edge, if it exists. Otherwise, the algorithm represents an edge as a straight line segment connecting node centers.

The parameter ip->margin specifies a boundary of margin points to be allowed around each node. It must be non-negative.

The parameter ip->fixed, if non-null, should point to an array of ng booleans. If ip->fixed[i] is true, graph gs[i] should be left at its original position. The packing will first first place all of the fixed graphs, then fill in the with the remaining graphs.

The function returns an array of points which can be used as the origin of the bounding box of each graph. If the graphs are translated to these positions, none of the graph components will overlap. The array returned is obtained from malloc and must be freed by the caller. If any problem occurs, putGraphs returns NULL. As a side-effect, at its start, putGraphs sets the bb of each graph to reflect its initial layout. Note that putGraphs does not do any translation or change the input graphs in any other way than setting the bb.

This function uses the bb field in Agraphinfo_t, the pos, xsize and ysize fields in nodehinfo_t and the spl field in Aedgeinfo_t.

 

int packGraphs (int ng, Agraph_t** gs, Agraph_t* root, pack_info* ip)

This function takes ng subgraphs gs of a root graph root and calls putGraphs with the given arguments to generate a packing of the subgraphs. If successful, it then invokes shiftGraphs to apply the new positions. It returns 0 on success.

 

int packSubgraphs (int ng, Agraph_t** gs, Agraph_t* root, pack_info* ip)

This function simply calls packGraphs with the given arguments, and then recomputes the bounding box of the root graph.  

Utility functions

The library provides several functions which can be used to tailor the packing based on graph attributes.  

pack_mode getPackMode (Agraph_t* g, pack_mode dflt)

This function returns a pack_mode associated with g. If the graph attribute "packmode" is "cluster", it returns l_clust; for "graph", it returns l_graph; for "node", it returns l_node; otherwise, it returns dflt.  

int getPack (Agraph_t* g, int not_def, int dflt)

This function queries the graph attribute "pack". If this is defined as a non-negative integer, the integer is returned; if it is defined as "true", the value dflt is returned; otherwise, the value not_def is returned.  

SEE ALSO

dot(1), neato(1), twopi(1), libgraph(3)
K. Freivalds et al., "Disconnected Graph Layout and the Polyomino Packing Approach", GD0'01, LNCS 2265, pp. 378-391.

 

BUGS

The packing does not take into account edge or graph labels.  

AUTHORS

Emden Gansner (erg@research.att.com).


 

Index

NAME
SYNOPSIS
DESCRIPTION
Creating components
Agraph_t** ccomps (Agraph_t* g, int* cnt, char* pfx)
Agraph_t** pccomps (Agraph_t* g, int* cnt, char* pfx, boolean* pinned)
int nodeInduce (Agraph_t* g)
int isConnected (Agraph_t* g)
Packing components
point* putGraphs (int ng, Agraph_t** gs, Agraph_t* root, pack_info ip)
int packGraphs (int ng, Agraph_t** gs, Agraph_t* root, pack_info* ip)
int packSubgraphs (int ng, Agraph_t** gs, Agraph_t* root, pack_info* ip)
Utility functions
pack_mode getPackMode (Agraph_t* g, pack_mode dflt)
int getPack (Agraph_t* g, int not_def, int dflt)
SEE ALSO
BUGS
AUTHORS

This document was created by man2html using the manual pages.
Time: 17:31:57 GMT, October 23, 2013

2. pack.9.man

Manpage of pack

pack

Section: Tk Built-In Commands (n)
Updated: 4.0
Index Return to Main Contents



 

NAME

pack - Geometry manager that packs around edges of cavity  

SYNOPSIS

pack option arg ?arg ...?



 

DESCRIPTION

The pack command is used to communicate with the packer, a geometry manager that arranges the children of a parent by packing them in order around the edges of the parent. The pack command can have any of several forms, depending on the option argument:

pack slave ?slave ...? ?options?
If the first argument to pack is a window name (any value starting with ``.''), then the command is processed in the same way as pack configure.
pack configure slave ?slave ...? ?options?
The arguments consist of the names of one or more slave windows followed by pairs of arguments that specify how to manage the slaves. See THE PACKER ALGORITHM below for details on how the options are used by the packer. The following options are supported:
-after other
Other must the name of another window. Use its master as the master for the slaves, and insert the slaves just after other in the packing order.
-anchor anchor
Anchor must be a valid anchor position such as n or sw; it specifies where to position each slave in its parcel. Defaults to center.
-before other
Other must the name of another window. Use its master as the master for the slaves, and insert the slaves just before other in the packing order.
-expand boolean
Specifies whether the slaves should be expanded to consume extra space in their master. Boolean may have any proper boolean value, such as 1 or no. Defaults to 0.
-fill style
If a slave's parcel is larger than its requested dimensions, this option may be used to stretch the slave. Style must have one of the following values:
none
Give the slave its requested dimensions plus any internal padding requested with -ipadx or -ipady. This is the default.
x
Stretch the slave horizontally to fill the entire width of its parcel (except leave external padding as specified by -padx).
y
Stretch the slave vertically to fill the entire height of its parcel (except leave external padding as specified by -pady).
both
Stretch the slave both horizontally and vertically.
-in other
Insert the slave(s) at the end of the packing order for the master window given by other.
-ipadx amount
Amount specifies how much horizontal internal padding to leave on each side of the slave(s). Amount must be a valid screen distance, such as 2 or .5c. It defaults to 0.
-ipady amount
Amount specifies how much vertical internal padding to leave on each side of the slave(s). Amount defaults to 0.
-padx amount
Amount specifies how much horizontal external padding to leave on each side of the slave(s). Amount may be a list of two values to specify padding for left and right separately. Amount defaults to 0.
-pady amount
Amount specifies how much vertical external padding to leave on each side of the slave(s). Amount may be a list of two values to specify padding for top and bottom separately. Amount defaults to 0.
-side side
Specifies which side of the master the slave(s) will be packed against. Must be left, right, top, or bottom. Defaults to top.

If no -in, -after or -before option is specified then each of the slaves will be inserted at the end of the packing list for its parent unless it is already managed by the packer (in which case it will be left where it is). If one of these options is specified then all the slaves will be inserted at the specified point. If any of the slaves are already managed by the geometry manager then any unspecified options for them retain their previous values rather than receiving default values.

pack forget slave ?slave ...?
Removes each of the slaves from the packing order for its master and unmaps their windows. The slaves will no longer be managed by the packer.
pack info slave
Returns a list whose elements are the current configuration state of the slave given by slave in the same option-value form that might be specified to pack configure. The first two elements of the list are ``-in master'' where master is the slave's master.
pack propagate master ?boolean?
If boolean has a true boolean value such as 1 or on then propagation is enabled for master, which must be a window name (see GEOMETRY PROPAGATION below). If boolean has a false boolean value then propagation is disabled for master. In either of these cases an empty string is returned. If boolean is omitted then the command returns 0 or 1 to indicate whether propagation is currently enabled for master. Propagation is enabled by default.
pack slaves master
Returns a list of all of the slaves in the packing order for master. The order of the slaves in the list is the same as their order in the packing order. If master has no slaves then an empty string is returned.
 

THE PACKER ALGORITHM

For each master the packer maintains an ordered list of slaves called the packing list. The -in, -after, and -before configuration options are used to specify the master for each slave and the slave's position in the packing list. If none of these options is given for a slave then the slave is added to the end of the packing list for its parent.

The packer arranges the slaves for a master by scanning the packing list in order. At the time it processes each slave, a rectangular area within the master is still unallocated. This area is called the cavity; for the first slave it is the entire area of the master.

For each slave the packer carries out the following steps:

[1]
The packer allocates a rectangular parcel for the slave along the side of the cavity given by the slave's -side option. If the side is top or bottom then the width of the parcel is the width of the cavity and its height is the requested height of the slave plus the -ipady and -pady options. For the left or right side the height of the parcel is the height of the cavity and the width is the requested width of the slave plus the -ipadx and -padx options. The parcel may be enlarged further because of the -expand option (see EXPANSION below)
[2]
The packer chooses the dimensions of the slave. The width will normally be the slave's requested width plus twice its -ipadx option and the height will normally be the slave's requested height plus twice its -ipady option. However, if the -fill option is x or both then the width of the slave is expanded to fill the width of the parcel, minus twice the -padx option. If the -fill option is y or both then the height of the slave is expanded to fill the width of the parcel, minus twice the -pady option.
[3]
The packer positions the slave over its parcel. If the slave is smaller than the parcel then the -anchor option determines where in the parcel the slave will be placed. If -padx or -pady is non-zero, then the given amount of external padding will always be left between the slave and the edges of the parcel.

Once a given slave has been packed, the area of its parcel is subtracted from the cavity, leaving a smaller rectangular cavity for the next slave. If a slave does not use all of its parcel, the unused space in the parcel will not be used by subsequent slaves. If the cavity should become too small to meet the needs of a slave then the slave will be given whatever space is left in the cavity. If the cavity shrinks to zero size, then all remaining slaves on the packing list will be unmapped from the screen until the master window becomes large enough to hold them again.  

EXPANSION

If a master window is so large that there will be extra space left over after all of its slaves have been packed, then the extra space is distributed uniformly among all of the slaves for which the -expand option is set. Extra horizontal space is distributed among the expandable slaves whose -side is left or right, and extra vertical space is distributed among the expandable slaves whose -side is top or bottom.  

GEOMETRY PROPAGATION

The packer normally computes how large a master must be to just exactly meet the needs of its slaves, and it sets the requested width and height of the master to these dimensions. This causes geometry information to propagate up through a window hierarchy to a top-level window so that the entire sub-tree sizes itself to fit the needs of the leaf windows. However, the pack propagate command may be used to turn off propagation for one or more masters. If propagation is disabled then the packer will not set the requested width and height of the packer. This may be useful if, for example, you wish for a master window to have a fixed size that you specify.  

RESTRICTIONS ON MASTER WINDOWS

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

PACKING ORDER

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

EXAMPLE


# Make the widgets
label .t -text "This widget is at the top"    -bg red
label .b -text "This widget is at the bottom" -bg green
label .l -text "Left
Hand
Side" label .r -text "Right
Hand
Side" text .mid .mid insert end "This layout is like Java's BorderLayout" # Lay them out pack .t -side top -fill x pack .b -side bottom -fill x pack .l -side left -fill y pack .r -side right -fill y pack .mid -expand 1 -fill both

 

SEE ALSO

grid(n), place(n)

 

KEYWORDS

geometry manager, location, packer, parcel, propagation, size


 

Index

NAME
SYNOPSIS
DESCRIPTION
THE PACKER ALGORITHM
EXPANSION
GEOMETRY PROPAGATION
RESTRICTIONS ON MASTER WINDOWS
PACKING ORDER
EXAMPLE
SEE ALSO
KEYWORDS

This document was created by man2html using the manual pages.
Time: 17:31:57 GMT, October 23, 2013

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