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1. dot User s Manual October 18 1993 Drawing graphs with dot past 1980 1982 1983 1985 1986 1987 1988 1989 1990 future SCCS make Bourne sh yacc Reiser cpp Cshell build vi emacs RCS A SYNED IMX d ksh IFS TTU 1 a nmake Peggy hd y ce nepp lt curses i gt ksh i PG2 Y DAG CSAS 3D File System Ansi cpp fdelta nmake 2 0 d CIA ksh 88 PEGASUS PML backtalk APP CIA ryacc DataShare Mosaic 1 va DOT DIA libft CoShell Software IS Architecture amp Libraries Adv Software Technology Figure 8 Drawing with constrained ranks dot User s Manual October 18 1993 12 cron AA yeast Drawing graphs with dot 13 1 digraph g 2 node shape record height 1 3 nodeO label lt f0 gt lt f1 gt G lt f2 gt 4 nodei label lt f0 gt lt f1 gt E lt f2 gt 5 node2 label lt f0 gt lt f1 gt BI lt f2 gt 6 node3 label lt f0 gt lt f1 gt F lt f2 gt 7 node4 label lt f0 gt lt f1 gt R lt f2 gt 8 node5 label lt f0 gt lt f1 gt H lt f2 gt 9 node6 label l2. gt parse weight 8 5i parse gt execute 6 main gt init style dotted T main gt cleanup 8 execute gt make_string printf Os init gt make_string 10 edge color red 11 main gt printf style bold label 100 times 12 make_string label make a nstring 13 node shape box style filled color 7 3 1 0 14 execute gt compare Figure 3 Fancy graph 100 times make a compare string P Figure 4 Drawing of fancy graph dot User s Manual October 18 1993 Drawing graphs with dot 5 2 Drawing Attributes The complete list of attributes that affect graph drawing is summarized in table 1 2 1 Shapes and Labels By default nodes are drawn with shape ellipse width 75 height 5 and labeled by the node name Other common shapes box circle etc are listed in table 1 The node shape plaintext is of particularly interest in that it draws a node without any outline an important convention in some kinds of diagrams When drawn a node s actual size is the greater of the requested size and the area needed for its text label By default edges are unlabeled Node and edge labels can be set explicitly as shown n figure 4 Though it is convenient that nodes are labeled with their names by default sometimes it is essential to set labels explicitly For example in drawing a file directory tree one might have several directories named src but each one must have a un
3. are drawn The arg lists are translated to PostScript notation For example a node with style setlinewidth 8 is drawn with a thick outline Here setlinewidth is a PostScript built in but user defined PostScript procedures are called the same way The definition of these procedures can be given in a library file loaded using 1 as shown above Edges have a dir attribute to set arrowheads dir may be forward the default back both or none This refers only to where arrowheads are drawn and does not change the underlying graph For example setting dir back does not exchange the endpoints of a directed edge unlike the dagprogram 2 3 Drawing Size and Spacing Often a drawing made with the default node sizes and separations is too big for the target printer or for the space allowed for a figure in a document There are several ways to try to deal with this problem First we will review how dot computes the final layout size A layout is initially made internally at its natural size using default settings unless ratio compress was set as described below By default nodes are at least 75 inches wide by 5 tall fonts are 14 points high nodes are separated by at least 25 and ranks by 5 There is no bound on the size or aspect ratio of the drawing so if the graph is large the layout is also large If you don t specify size or ratio then the natural size layout is printed dot User s Manual October 18 1993 Drawing
4. graphs with dot 9 The easiest way to control the output size of the drawing is to set size x y in the graph file or on the command line using G This determines the bounding box of the final layout For example size 7 5 10 fits on an 8 5x11 page assuming the default page orientation no matter how big the initial layout ratio also affects layout size There are a number of cases depending on the settings of size and ratio Case 1 ratio was not set If the drawing already fits within the given size then nothing happens Otherwise the drawing is reduced uniformly enough to make the critical dimension fit If ratio was set there are four subcases Case 2a If ratio x where x is a floating point number then the drawing is stretched adding whitespace to achieve the requested ratio expressed as drawing width height For example ratio 2 0 makes the drawing twice as wide as it is high Then the layout is scaled using size as in Case 1 Case 2b If ratio fill and size y was set then the drawing is stretched adding whitespace to achieve the ratio x y The effect is that all of the bounding box given by size is filled Then scaling is performed as in Case 1 Case 2c If ratio compress and size z y was set then the initial layout is compressed to attempt to fit it fit it the given bounding box This trades off layout quality balance and symmetry to pack the layout more tightly Then scaling is performed as in Case 1 Case 2d
5. gt 015 794 I lt p gt node7 label lt n gt s19 659 lt p gt node0 f0 gt nodei n node0 f1 gt node2 n node0 f2 gt node3 n node0 f5 gt node4 n node0 f6 gt node5 n node2 p gt node6 n node4 p gt node7 n Figure 13 Hash table graph file Pal 719 _ Pal 805 Srei pois 794 oo w Soo Figure 14 Drawing of hash table dot User s Manual October 18 1993 Drawing graphs with dot 16 digraph G subgraph clusterO node style filled color white style filled color lightgrey a0 gt al gt a2 gt a3 label process 1 process 2 brocess 1 subgraph clusteri node style filled bO gt b1 gt b2 gt b3 label process 2 color blue start gt a0 start gt b0 al gt b3 b2 gt a3 a3 gt a0 a3 gt end b3 gt end start shape Mdiamond end shape Msquare Figure 15 Process diagram with clusters 3 1 Clusters A cluster is a subgraph placed in its own distinct rectangle of the layout A subgraph is rec ognized as a cluster when its name has the prefix cluster unless the graph s clusterrank none Cluster labels fonts colors and styles can be set in the usual way Clusters are drawn by a recursive technique that computes a rank assignment and internal ordering of nodes within clusters Figure 15 through 17 are cluster layouts and the corresponding graph fil
6. gt 1983 gt 1985 gt 1986 gt 1987 gt 1988 gt 1989 gt 1990 gt future ancestor programs Bourne sh make SCCS yacc cron Reiser cpp Cshell emacs build vi lt curses gt RCS C rank same Software IS Configuration Mgt Architecture amp Libraries Process node shape box rank same past SCCS make Bourne sh yacc cron rank same 1978 Reiser cpp Cshell rank same 1980 build emacs vi rank same 1982 RCS lt curses gt IMX SYNED rank same 1983 ksh IFS TTU rank same 1985 nmake Peggy rank same 1986 Cx ncpp ksh i lt curses i gt PG2 rank same 1987 Ansi cpp nmake 2 0 3D File System fdelta DAG CSAS rank same 1988 CIA SBCS ksh 88 PEGASUS PML PAX backtalk rank same 1989 CIA APP SHIP DataShare ryacc Mosaic rank same 1990 libft CoShell DIA IFS i kyacc sfio yeast ML X DOT rank same future Adv Software Technology nhanh PEGASUS PML gt ML X SCCS gt nmake SCCS gt 3D File System Ssccs gt RCS make gt nmake make gt build Bourne sh gt Cshell Bourne sh gt ksh Reiser cpp gt ncpp Cshell gt ksh Figure 7 Graph with constrained ranks
7. main gt malloc main gt strcpy main gt getopt main gt init_index main gt strlen fan gt fatal fan gt ref fan gt interp_err ciafan gt def fan gt free computefan gt stdprintf computefan gt get_sym_fields fan gt exit fan gt malloc increment gt strcmp computefan gt malloc fan gt stdsprintf fan gt strlen computefan gt strcmp computefan gt realloc computefan gt strlen debug gt sfprintf debug gt strcat stringdup gt malloc fatal gt sfprintf stringdup gt strcpy stringdup gt strlen fatal gt exit subgraph cluster_error h label error h interp_err subgraph cluster_sfio h label sfio h sfprintf subgraph cluster_ciafan c label ciafan c ciafan computefan increment subgraph cluster_util c label util c stringdup fatal debug subgraph cluster_query h label query h ref def subgraph cluster_field h get_sym_fields subgraph cluster_stdio h label stdio h stdprintf stdsprintf subgraph cluster_ lt libc a gt getopt subgraph cluster_stdlib h label stdlib h exit malloc free realloc subgraph cluster_main c main subgraph cluster_index h init_index subgraph cluster_string h label string h strcpy strlen strcmp strcat Figure 17 Call graph file dot User s Manual October 18 1993 Drawing graphs with dot 19 but doesn t collapse as many edges as Newbery s algorithm 4 Command Line Option
8. or hard spaces Also note that records sometimes look better if their input height is set to a small value so the text labels dominate the actual size as illustrated in figure 9 Otherwise the default node size 75 by 5 is assumed as in figure 11 The example of figures 13 and 14 uses left to right drawing in a layout of a hash table dot User s Manual October 18 1993 Drawing graphs with dot 14 Figure 10 Drawing of binary search tree digraph structs node shape record structi shape record label lt f0 gt left lt f1 gt middle lt f2 gt right struct2 shape record label lt f0 gt onel lt f1 gt two struct3 shape record label hello nworld b cl lt here gt dle l f g h structi f1 gt struct2 f0 structi f 2 gt struct3 here ONOoOPWBNE Figure 11 Records with nested fields Figure 12 Drawing of records dot User s Manual October 18 1993 Drawing graphs with dot 15 digraph G nodesep 05 rankdir LR node shape record width 1 height 1 nodeO label lt f0 gt lt f1 gt lt f2 gt lt f 3 gt lt f4 gt lt f5 gt lt f6 gt height 2 5 node width 1 5 node1 label lt n gt n14 719 lt p gt node2 label lt n gt a1 805 I lt p gt node3 label lt n gt i9 718 I lt p gt node4 label lt n gt e5 989 lt p gt node5 label lt n gt t20 959 I lt p gt node6 label lt n
9. 1 4 lightskyblue 1 4 lightslateblue 1 4 mediumblue mediumslateblue midnightblue navy navyblue powderblue royalblue 1 4 skyblue 1 4 slateblue 1 4 steelblue 1 4 Magentas blueviolet darkorchid 1 4 darkviolet magenta 1 4 mediumorchid 1 4 mediumpurple 1 4 mediumvioletred orchid 1 4 palevioletred 1 4 plum 1 4 purple 1 4 violet violetred 1 4
10. Drawing graphs with dot Eleftherios Koutsofios Stephen C North AT amp T Bell Laboratories Murray Hill NJ dot draws directed graphs as hierarchies Like its predecessor dag it is a Unix filter makes good drawings and runs quickly Its important new features are node ports for drawing data structures with pointers improved placement of nodes edge splines and labels cluster layouts and an underlying file language for graph tools Here is a reduced module dependency graph of the SML NJ compiler The layout took 3 5 seconds of user time on an HP 9000 730 computer dot User s Manual October 18 1993 Drawing graphs with dot 2 1 Basic Graph Drawing dot draws directed graphs It reads attributed graph text files and writes drawings either as graph files or in a graphics language such as PostScript dot takes four main steps in drawing a graph Knowing about these helps you to un derstand what kind of layouts dot makes and how you can modify its layouts The first step assigns discrete ranks to nodes In a top to bottom drawing ranks determine Y coor dinates Edges that span more than one rank are broken into chains of virtual nodes and unit length edges The second step orders nodes within ranks to avoid crossings The third step sets X coordinates of nodes to keep edges short The last step routes edge splines This is the same general approach as dag which in turn builds on the w
11. If ratio auto then size is ignored and dot computes an ideal size using the following heuristic it first attempts to fit the drawing on one page by reducing to not less than 50 of its original size Otherwise the drawing is printed on multiple pages using the full area of each page and not reducing under 50 At this point if page is not set then the final layout is printed as one page If page a y is set then the layout is printed as a sequence of pages that can tiled or assembled into a mosaic Common settings are page 8 5 11 or page 11 17 These values refers to the size of the physical device and are independent of landscape mode For tiled layouts you may find it helpful to set smaller margins the default is margin 5 Although you can set margin 0 unfortunately many bitmap printers have an Internal hardware margin that cannot be overridden If rotate 90 is set then the layout is printed in landscape mode The X axis of the layout would be along the Y axis of each page This does not affect the dots interpretation of size ratio or page A common problem is that a large graph drawn at a small size yields unreadable node labels To make larger labels something has to give There is a limit to the amount of readable text that can fit on one page Often you can draw a smaller graph by extracting an interesting piece of the original graph before running dot We have some tools that help with this e sccmap decompos
12. ace papayawhip peachpuff 1 4 seashell 1 4 snow 1 4 thistle 1 4 wheat 1 4 white whitesmoke Greys darkslategray 1 4 dimgray gray gray 0 100 lightgray lightslategray slategray 1 4 Blacks black Reds coral 1 4 crimson darksalmon deeppink 1 4 firebrick 1 4 hotpink 1 4 indianred 1 4 lightpink 1 4 lightsalmon 1 4 maroon 1 4 mediumvioletred orangered 1 4 palevioletred 1 4 pink 1 4 red 1 4 salmon 1 4 tomato 1 4 violetred 1 4 Browns beige brown 1 4 burlywood 1 4 chocolate 1 4 darkkhaki khaki 1 4 peru rosy brown 1 4 saddlebrown sandybrown sienna 1 4 tan 1 4 Oranges darkorange 1 4 orange 1 4 orangered 1 4 Yellows darkgoldenrod 1 4 gold 1 4 goldenrod 1 4 greenyellow lightgoldenrod 1 4 lightgoldenrodyellow lightyellow 1 4 palegoldenrod yellow 1 4 yellowgreen Greens chartreuse 1 4 darkgreen darkolivegreen 1 4 darkseagreen 1 4 forestgreen green 1 4 greenyellow lawngreen lightseagreen limegreen mediumseagreen mediumspringgreen mintcream olivedrab 1 4 palegreen 1 4 seagreen 1 4 springgreen 1 4 yellowgreen Cyans aquamarine 1 4 cyan 1 4 darkturquoise lightcyan 1 4 mediumaquamarine mediumturquoise paleturquoise 1 4 dot User s Manual October 18 1993 23 turquoise 1 4 Blues aliceblue blue 1 4 blueviolet cadetblue 1 4 cornflowerblue darkslateblue deepskyblue 1 4 dodgerblue 1 4 indigo lightblue
13. atic display of hierarchized graphs for computer aided deci sion analysis IEEE Transactions on Software Engineering SE 12 4 538 546 April 1980 Emden R Gansner Eleftherios Koutsofios Stephen C North and Kiem Phong Vo A Technique for Drawing Directed Graphs IEEE Trans Sofware Eng 19 3 214 230 May 1993 Frances J Newbery Edge Concentration A Method for Clustering Directed Graphs In 2nd International Workshop on Software Configuration Manage ment pages 76 85 October 1989 Published as ACM SIGSOFT Software En gineering Notes vol 17 no 7 November 1989 Stephen C North Neato User s Guide Technical Report 59113 921014 14TM AT amp T Bell Laboratories Murray Hill NJ 1992 K Sugiyama S Tagawa and M Toda Methods for Visual Understanding of Hierarchical System Structures IEEE Transactions on Systems Man and Cybernetics SMC 11 2 109 125 February 1981 John Warfield Crossing Theory and Hierarchy Mapping IEEE Transactions on Systems Man and Cybernetics SMC 7 7 505 523 July 1977 dot User s Manual October 18 1993 Drawing graphs with dot 21 A Graph File Grammar The following is an abstract grammar of graph files Terminals are shown in typewriter font and nonterminals in italics Angle brackets and indicate grouping when needed Double line brackets and enclose optional items Vertical bars separate alternatives graph strict digraph graph id stmt list stmt lis
14. e into strongly connected components e tred compute transitive reduction remove edges implied by transitivity dot User s Manual October 18 1993 Drawing graphs with dot 10 e gpr raph processor to select nodes or edges and contract or remove the rest of the graph e unflatten improve aspect ratio of trees by staggering the lengths of leaf edges With this in mind here are some thing to try on a given graph Increase the node fontsize Use smaller ranksep and nodesep 1 2 3 Use ratio auto 4 Use ratio compress and give a reasonable size 5 A sans serif font such as Helvetica may be more readable than Times when reduced 2 4 Node and Edge Placement Sometimes it is natural to make edges point from left to right instead of from top to bottom If rankdir LR in the top level graph the drawing is rotated in this way TB top to bottom is the default BT seems potentially useful for drawing upward directed graphs but hasn t been impelemented In some graphs you could achieve the same effect by reversing the endpoints of edges and setting their dir back In graphs with time lines or in drawings that emphasize source and sink nodes you may need to constrain rank assignments The set of a subgraph may be set to minrank maxrank or samerank This constrains the nodes in the subgraph Figures 7 and 8 illustrate using subgraphs for controlling rank assignment In some graphs the left to right ordering
15. e is a way to implement custom node shapes the details are beyond the scope of this user s guide Please contact the authors for further information 2 2 Graphics Styles Nodes and edges have color and style attributes A color value can be a hue saturation brightness triple three floating point numbers between 0 and 1 or one of the colors names listed in Appendix B borrowed from some version of the X window system The numerical The escape N is an internal symbol for node names dot User s Manual October 18 1993 Drawing graphs with dot Node Attributes color fontcolor fontname fontsize height width label shape style black black Times Roman 14 253 75 node name ellipse node shape color type face color PostScript font family point size of label height and width in inches any string ellipse box circle doublecircle plaintext record polygon graphics options e g bold dotted filled diamond Edge Attributes color decorate dir fontcolor fontname fontsize id label minlen style weight Graph Attributes center clusterrank color concentrate fontcolor fontname fontsize label margin mclimit nodesep nslimit ordering orientation page rank rankdir ranksep ratio size black forward black Times Roman 14 local black black Times Roman portrait edge stroke color if set draws a line connecting labels with their edges forward back both o
16. es 3 2 Concentrators Setting concentrate true on the top level graph enables an edge merging technique to reduce clutter in dense layouts Edges are merged when they run parallel and have a common endpoint A beneficial side effect in fixed sized layouts is that removal of these edges often permits larger more readable labels While dots concentrators look somewhat like Newbery s New89 they are found by searching the edges in the layout not by detecting complete bipartite graphs in the underlying graph Thus the dot approach runs much faster dot User s Manual October 18 1993 Drawing graphs with dot main sfio h sfprintf ciafane 17 lt error h uery h fatal Cinterp_emt ref def computa r stdlib h stdio h Yeing h exit malloc free Cealloc Gadsprintt sprint Cirepy streat strlen stremp get_sym_fields Figure 16 Call graph with labeled clusters dot User s Manual October 18 1993 Drawing graphs with dot 18 1 2 3 4 Bs 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 digraph G size 8 6 ratio fill node fontsize 24 ciafan gt computefan fan gt increment computefan gt fan stringdup gt fatal main gt exit main gt interp_err main gt ciafan main gt fatal
17. ique node identifier The inode number or full path name are suitable unique identifiers Then the label of each node can be set to the file name within its directory In multi line labels n 1 r terminate lines that are centered or left or right justified Graphs and cluster subgraphs may also have labels The default font is 14 point Times Roman in black Other font families sizes and colors may be selected Font names should be compatible with the target interpreter usually PostScript It is best to use only the standard font families Times Helvetica Courier or Symbol as these are guaranteed to work with any target graphics language For example Times Italic Times Bold or Courier are portable but AvanteGarde Demi0blique is not Nodes with shape record or polygon have special properties Section 3 reviews some details of using records Polygons are useful for many shapes that are not predefined They are parameterized by number of sides peripheries orientation skew and distortion as illustrated in figures 5 and 6 peripheries is the number of borders For example a doublecircle has 2 peripheries orientation is clockwise rotation from the X axis in degrees skew is a floating point number usually between 1 0 and 1 0 that distorts the shape by slanting it from top to bottom for example turning a box into a parallelogram distortion shrinks from top to bottom for example turning a box into a trapezoid Though ther
18. matically generate colors Color name lookup case and puncutation and insensitive so warmgrey and Warm_Grey are equivalent We can offer a few hints regarding use of color in graph drawings First avoid using too many bright colors A rainbow effect is confusing It s better to choose a narrower range of colors or to vary saturation along with hue Second when nodes are filled with dark or very saturated colors labels seem to be more readable with fontcolor white and fontname Helvetica We also have PostScript functions for dot that create outline fonts from plain fonts Third you can define your own color space by redefining nodecolor edgecolor or graphcolor in a library file For example to use RGB colors place the following line in a file lib ps nodecolor setrgbcolor bind def Use the 1 command line option to load this file dot Tps l lib ps file dot o file ps style controls miscellaneous graphics features of nodes edges graphs or subgraphs The style is a list of primitives with optional argument lists The predefined primitives are filled solid dashed dotted bold and invis filled when applied to nodes or clusters shades inside the boundary of the object using its color If the color is not set light grey is used as the default User defined style primitives can be implemented as custom PostScript procedures Such primitives are executed inside the gsave context of a graph node or edge before any of its marks
19. me n x1 Y 2 Y2 Ln Yn Opt_text opt_x opt_y n is the number of coordinate pairs that follow as Bezier spline control points If the edge is labeled then the label text and coordinates are listed as the rightmost three items on the line The last line is always stop dot User s Manual October 18 1993 Drawing graphs with dot 22 C Layout Attributes Layout coordinates are in the default PostScript coordinate system Node coordinates refer to their center points The edge spline is a list of 3n 1 points plus optional ps and optional Pe points The 3n 1 points are the Bezier control points Points po p1 p2 p33 are the first bezier spline p3 p4 ps pe are the second etc The p point is present if there s an arrow at po In this case the arrow is from po to point ps where p is actually on the node s boundary and pg is further away If there is no arrow po is on the node s boundary Similarly pe is for an arrow on the other endpoint of the edge Currently edge points are listed top to bottom or left to right regardless of the orien tation of the edge This may change dot User s Manual October 18 1993 Drawing graphs with dot D Color Names Whites antiquewhite 1 4 azure 1 4 bisque 1 4 blanchedalmond cornsilk 1 4 floralwhite gainsboro ghostwhite honeydew 1 4 ivory 1 4 lavender lavenderblush 1 4 lemonchiffon 1 4 linen mintcream mistyrose 1 4 moccasin navajowhite 1 4 oldl
20. nerated for each distinct edge between the same pair of nodes An id may be any string 6 Conclusions dot produces nicer drawings than dag and has some features to help make more readable drawings It is not as fast as dag Since it still takes only a second or two on reasonable inputs we feel the new features more than make up for this In writing graph drawing programs we have found that it does not take long to get the first drawings but it takes a great deal of work to get truly good drawings While there is still plenty of room for improvement in dot we have accomplished our principal goals concerning aesthetics performance and new features Since the basic algorithms of dot work well we have a good basis for further research into problems such as methods for drawing large graphs and on line animated graph drawing dot User s Manual October 18 1993 Drawing graphs with dot 20 7 Acknowledgements We would like to thank Emden Gansner and Phong Vo for discussions and advice regarding graph drawing algorithms and program design The graph library uses Phong s splay tree dictionary library Also the users of dag shared many good suggestions with us Emden Gansner Guy Jacobson and Randy Hackbarth reviewed earlier drafts of this manual John Ellson wrote the generalized polygon shape and took pains to make it robust and efficient References Car80 GKNV93 New89 Nor92 STT81 War77 M Carpano Autom
21. of nodes is important If a subgraph has ordering out then out edges within the subgraph having the same tail node fan out from left to right in their order of creation Also when nodes are constrained to the same rank edges with non zero weight between them are aimed across the rank in the same direction left to right or top to bottom in a rotated drawing as far as possible This fact may be exploited to adjust node ordering by placing invisible edges style invis where needed Fine tuning should be approached cautiously dot works best when it can makes a layout without much help or interference in its placement of individual nodes and edges Layouts can be adjusted somewhat by increasing the weight of certain edges or by creating invisible edges or nodes using style invis and sometimes even by rearranging the order of nodes and edges in the file But this can backfire because the layouts are not necessarily stable with respect to changes in the input graph One last adjustment can invalidate all previous changes and make a very bad drawing A future project we have in mind is to combine the mathematical layout techniques of dot with an interactive front end that allows user defined hints and constraints dot User s Manual October 18 1993 Drawing graphs with dot digraph asde91 ranksep 75 size 7 5 7 5 node shape plaintext fontsize 16 the time line graph past gt 1978 gt 1980 gt 1982
22. ork of Warfield War77 Carpano Car80 and Sugiyama STT81 We refer the reader to KNV93 for explanation of dot s algorithms dots graph language has three kinds of items graphs nodes and edges The main outermost graph can be graph undirected or a digraph directed Because dot makes layouts of directed graphs all the examples in this user s guide use digraph We have written a separate layout utility feato to draw undirected graphs Nor92 Within a main graph a subgraph defines a subset of nodes and edges Figure 1 is an example graph in dot s language Line 1 gives the graph name and type The following lines create nodes edges or subgraphs and set attributes Names may be C identifiers numbers or quoted C strings Quotes protect punctuation or white space A node is created the first time its name appears in the file An edge is created when nodes are joined by the edge operator gt In the example line 2 makes edges from main to parse and from parse to execute Running dot on this file say graphi dot yields the drawing of figure 2 dot Tps graphi dot o graphi ps The command line option Tps selects PostScript EPSF output graph1 ps may be printed displayed by a PostScript viewer or embedded in another document It is often useful to adjust the representation or placement of nodes and edges in the layout This is done by setting attributes of nodes edges or subgraphs in the input file Attribute
23. r none type face color PostScript font family point size of label optional value to distinguish multiple edges label if not empty minimum rank distance between head and tail graphics options e g bold dotted filled integer reflecting importance of edge when set centers drawing on page may be global or none cluster box stroke color enables edge concentrators when TRUE type face color PostScript font family point size of label any string margin included in page if set to f adjusts mincross iterations by f separation between nodes in inches if set to f bounds network simplex iterations by f number of nodes out for ordered edges may be set to landscape unit of pagination e g 8 5 11 same min or max LR left to right or TB top to bottom separation between ranks in inches approximate aspect ratio desired or fill drawing bounding box in inches Table 1 Drawing attributes dot User s Manual October 18 1993 Drawing graphs with dot 7 Figure 5 Example of polygonal shapes for nodes digraph G a gt b gt c b gt d a shape polygon sides 5 peripheries 3 color blue_light style filled c shape polygon sides 4 skew 4 label hello world d shape invtriangle e shape polygon sides 4 distortion 7 Figure 6 Listing of graph with polygonal shapes dot User s Manual October 18 1993 Drawing graphs with dot 8 form is convenient for scripts or tools that auto
24. s By default dot operates in filter mode writing graphs in the input format with layout attributes appended Tps sets PostScript output Tpcl emits HPGL 2 with PCL 5 wrappers for HP Laserwriters Thpgl emits pure HPGL for wide bed pen plotters Tmif emits FrameMaker MIF files In this mode graph layouts can be loaded into FrameMaker and edited manually FrameMaker is limited to 8 basic colors Gname value sets a graph attribute default value Often it is convenient to set size pagination and related values on the command line rather than in the graph file Note that file contents override command line arguments N or E instead of G set default node or edge attributes 1 loads graphics library files o sets the output file v requests verbose output In processing large layouts the verbose messages may give some estimate of dots progress V prints the version number 5 Miscellaneous There are several features of the graph file language worth noting In the top level graph heading a graph may be declared a strict digraph This forbids the creation of self arcs and multi edges they are ignored in the input file If a subgraph appears with a body more than once in a graph file its contents are the union of all the nodes and edges An edge id is an optional string for referencing an edge that was previously created When set the triple tail node head node key form a unique edge key Otherwise a new internal id is ge
25. s are name value pairs of character strings Figures 3 and 4 illustrate some layout attributes In the listing of figure 3 line 2 sets the graph s size to 4 4 all dimensions are in inches This attribute controls the bounding box the drawing is scaled as necessary to fit Node or edge attributes are set off in square brackets In line 3 the node main is assigned shape box The edge in line 4 is straightened by increasing its weight the default is 1 The edge in line 6 is drawn as a dotted line Line 8 makes edges from execute to make_string and printf In line 10 the default edge color is set to red This affects any edges created after this point in the file Line 11 makes a bold edge labeled 100 times In line 12 node make_string is given a multi line label Line 13 changes the default node to be a box filled with a shade of blue The node compare inherits these values Unlike dag the GS command is not needed dot User s Manual October 18 1993 Drawing graphs with dot 1 digraph G 2 main gt parse gt execute 3 main gt init 4 main gt cleanup 5 execute gt make_string 6 execute gt printf T init gt make_string 8 main gt printf 9 execute gt compare Figure 1 Small graph make_string compare Figure 2 Drawing of small graph dot User s Manual October 18 1993 Drawing graphs with dot 1 digraph G 2 size 4 4 3 main shape box this is a comment 4 main
26. t stmt stmt lst stmt attr stmt node stmt edge stmt subgraph id id attr stmt graph node edge attr list attr list id id attr list node stmt node id opt attrs node id idj id opt attrs attr list edge stmt node id subgraph edgeRHS opt attrs edgeRHS _ edgeop node id subgraph edgeRHS subgraph subgraph id stmt list subgraph id An id is any alphanumeric string not beginning with a digit but possibly including underscores or a number or any quoted string possibly containing escaped quotes An edgeop is gt in directed graphs and in undirected graphs Semicolons aid readability but are not required except in the rare case that a named sub graph with no body immediate preceeds an anonymous subgraph because under precedence rules this sequence is parsed as a subgraph with a heading and a body B Plain Output File Format Tplain The plain output format of dot lists node and edge coordinates that are usually needed by front end programs in a line oriented style The first line is graph scalefactor bounding_bor_z bounding_bor_y All coordinates are in default units 1 72 of an inch unscaled The next group of lines list the nodes in the format node name x y rsize ysize label_text The name is a unique identifier If it contains whitespace or punctuation it is quoted The next group of lines list edges edge tatlname headna
27. t f0 gt lt f1 gt Y lt f2 gt 10 node7 label lt f0 gt lt f1 gt A lt f2 gt J 11 node8 label lt f0 gt lt f1 gt C lt f2 gt J 12 nodeO f2 gt node4 f1 13 nodeO f0 gt nodei f1 14 nodei f0 gt node2 f1 15 nodei f 2 gt node3 f1 16 node2 f 2 gt node8 f1 17 node2 f0 gt node7 f1 18 node4 f 2 gt node6 f1 19 node4 f0 gt node5 f1 20 Figure 9 Binary search tree using records 3 Node Ports A node port is a point where edges may attach to a node When an edge is not attached to a port it is aimed at the node s center A node with a port specifier has the syntax name port The names and bindings of ports can differ from one node to another depending on shapes and other attributes Presently only the record shape has ports This shape represents a record as recursive lists of labeled boxes A port refers to the center of one of the boxes Ports are created by inserting the construct lt portid gt in a box label as shown in figures 9 and 10 Figures 11 and 12 shows how recursive records are drawn Vertical bars separate fields at the same level while curly braces enclose subfield lists Port identifiers are enclosed in angle brackets Literal braces vertical bars and angle brackets must be escaped Spaces are interpreted as separators between tokens similar to the way most typesetting programs work so they must be escaped if you want fixed
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