VCG | XVCG(1l) VCG | XVCG(1l)NAME
VCG tool - visualization of compiler graphs
SYNOPSIS
vcg [options] [filename]
xvcg [options] [filename]
SYNOPSIS FOR SEQUENCES OF GRAPH SPECIFICATIONS
vcg -multi [options] [filename] [options] [filename] ...
xvcg-multi [options] [filename] [options] [filename] ...
DESCRIPTION
The VCG tool reads a VCG specification and visualizes the graph. If
not all positions of nodes are fixed, the tool lays the graph out using
several heuristics as reducing the number of crossings, minimizing the
size of edges, centering of nodes. The specification language of the
VCG tool is nearly compatible to GRL, the language of the Edge tool,
but contains many extensions. The VCG tool allows folding of dynami‐
cally or statically specified regions of the graph. It uses colors and
runs on X11. (An older version runs on Sunview.)
GENERAL OPTIONS
- The input is stdin instead of a file.
-h | -? Print a help message about the usage of the tool.
-v | -version Print a version and copyright message.
-silent Be silent during the layout. No messages or warnings
are produced.
-nocolors | -blackwhite
Do not use colors on a color screen. On a monochrom
screen the graph is drawn in black & white even if it is
specified with colors. On a color screen, this mode is
simulated, if this option is selected. The option is
useful, if the VCG tool conflicts with other programs
that need colors.
-e <num> | -error <num>
Stop after <num> errors during parsing of the specifica‐
tion (default: 16).
-a <num> | -animation <num>
Start the tool as animation handler. This implies that
the tool is controlled by signals (USRSIG1, USRSIG2)
from an external program. The signal USRSIG1 causes the
VCG tool to open the display window and reload its input
file. The signal USRSIG2 causes the VCG tool to close
the display window. The tool processes the input and
indicates the completion of the processing to the con‐
trolling program. If <num> is greater 0, this indica‐
tion is done by sleeping <num> seconds and touching the
input file afterwards such that its time stamp is
refreshed. If <num> is less than 0, this indication is
done by sleeping - <num> seconds and sending signal USR‐
SIG1 to the caller process afterwards.
-m | -multi Read multiple files one after another to display a
sequence of graphs. Instead of an exit of the tool, the
next file is read. The option -multi must be specified
before the first input file.
-bary Use bary centering to reduce the number of edge cross‐
ings (default).
-median Use median centering instead of bary centering to reduce
the number of crossings. On graphs with large average
degree of edges, bary centering might be faster.
-barymedian Use a hybrid method to reduce the number of edge cross‐
ings. Bary centering is used for all nodes with differ‐
ent bary values. For nodes with same bary values, the
crossing reduction heuristics normally has a random
effect. With this hybrid method, the crossing reduction
of nodes with same bary values is done by median center‐
ing.
-medianbary Use a hybrid method to reduce the number of edge cross‐
ings. Median centering is used for all nodes with dif‐
ferent median values. For nodes with same median val‐
ues, the crossing reduction heuristics normally has a
random effect. With this hybrid method, the crossing
reduction of nodes with same median values is done by
bary centering.
-notune | -nofinetune
Switch the fine tuning layout phase off. Fine tuning is
a postprocessing phase after partitioning of nodes into
layers. Fine tuning changes the layers of nodes to min‐
imize the length of edges. If this phase is switched
off, it yield a less compact distribution of nodes in
the levels.
-manhattan | -orthogonal
Switch the orthogonal manhattan layout on. This forces
edges of gradient 0 or 90 degree. The result of this
layout might be more aesthetical, if additionally the
priority layout phase with straight line tuning is used.
Thus, these phases are switched on, too, unless priority
layout and straight line tuning is switched explicitly
off.
-nomanhattan | -noorthogonal
Switch the orthogonal manhattan layout explicitly off.
-smanhattan Use the orthogonal manhattan layout without separation
of horizontal line segments. Horizontal line segments
are shared between different edges. This looks nice for
trees but might be confusing in general, because the
location of an edge might be ambiguously.
-nosmanhattan Switch the orthogonal manhattan layout without separa‐
tion explicitly off.
-prio Switch the priority layout on. This forces straight
long edges with gradient 90 degree during the node
placement phase. The straight line tuning phase can be
used to improve the priority layout. Thus, this phase
is switched on, too, unless straight line tuning is
switched explicitly off.
-noprio Switch the priority layout explicitly off.
-straight Switch the straight line tuning phase on. This phase
forces straight long edges with gradient 90 degree. It
can be used to improve the priority layout.
-nostraight Switch the straight line tuning phase explicitly off.
-nonearedge Do not allow near edges in the layout.
-l | -latelabels
Create the labels after the partitioning of edges. This
has only an effect if labels are shown in a nondirty
way. If labels are created after the partitioning of
edges, the layout will be a little bit wider and may
have less crossings. But note that sometimes this lay‐
out may also be worser than the normal layout.
-hidesingles | -ignoresingles
Ignore single nodes (nodes without visible edges) that
are not connected with the remaining graph. These nodes
are sometimes not of interest, but would spread the lay‐
out if they were visible.
-s | -summarize
Switch edge summary layout on. Multiple edges between
the same source and target node are summarized if they
have the same visible appearance. This reduces the num‐
ber of visible edges.
OPTIONS FOR THE LAYOUT SPEED
The speed of the layout process can be influenced by selecting time
limits and iteration bounds of the different layout phases. Optional
layout phases can completely be skipped. But note that we need a mini‐
mal time for each graph, in order to initialize the internal data
structures. Furthermore, a fast layout is probably also an ugly lay‐
out.
-t <num> | -timelimit <num>
Set the time limit to <num> seconds of real time. If
the time limit is exceeded, the fastest possible layout
mode is switched on. This may yield a very ugly layout.
Of course, a time limit does not mean that the layout
really needs so much time: The layout may be faster,
because the graph structure is very simple, or it may be
slower, because even the fastest possible layout already
exceeds the time limit. Further note, that the layout
depends on the real time, i.e. on the load of the com‐
puter. Thus, given a time limit, two identical trys need
not to give identical results.
-f | -fast Switch the fast and dirty and ugly mode on. The layout
phase will be very fast, but the layout will be ugly.
This is helpful on very large graphs where aesthetic
visibility is of minor importance. The option -fast
implies -bmax 2 -cmax 2 -pmax 2 -rmax 2 -smax 2.
-b <num> | -bmax <num> | -bending <num>
Set the maximal number of iterations used for the reduc‐
tion of edge bendings to <num>. Edge bendings are used
to avoid that edges are drawn across nodes. Reducing
the number of iterations results in a faster but ugly
layout, i.e. to much bendings occur. The default value
is 100.
-c <num> | -cmax <num> | -crossing <num>
Set the maximal number of iterations used for the reduc‐
tion of edge crossings to <num>. The edge crossing
reduction method is called bary centering or median cen‐
tering. These may be very time consuming on large
graphs. Reducing the number of iterations results in a
faster but ugly layout. As default, the method is iter‐
ated as long as improvements are possible.
-cmin <num> Set the minimal number of iterations used for the reduc‐
tion of edge crossings to <num>. The crossing reduction
method tries to detect improvements of the layout. If
an iteration of that method does not yield an improv‐
ment, the method normally stops. But this situation
might be a local minimum of the quality of the layout,
i.e. further iterations might find a better layout.
Thus, the minimal number of iterations can be specified.
The default value is 0.
-p <num> | -pmax <num> | -pendulum <num>
Set the maximal number of iterations used for the bal‐
ancing by the pendulum method to <num>. The pendulum
method calculates the x co-ordinates of nodes such that
the layout is medium dense and balanced. It tries to
avoid extreme gradients of edges. It works like a pen‐
dulum where the nodes are the balls, the edges are the
strings and uppermost nodes are fixed on the ceiling.
Reducing the number of iterations results in a faster
but ugly layout. The default value is 100.
-pmin <num> Set the minimal number of iterations used for the bal‐
ancing by the pendulum method to <num>. If an itera‐
tion of that method does not yield an improvment, the
method normally stops. But this situation might be a
local minimum of the quality of the layout, i.e. further
iterations might find a better layout. Thus, the mini‐
mal number of iterations can be specified. The default
value is 0.
-r <num> | -rmax <num> | -rubberband <num>
Set the maximal number of iterations used for the bal‐
ancing by the rubberband method to <num>. The rubber‐
band method calculates the x co-ordinates of nodes such
that the nodes are centered relatively to their incoming
and outgoing edges. It works like a network where the
edges pull on the nodes like rubberbands. Reducing the
number of iterations results in a faster but ugly lay‐
out. The default value is 100.
-rmin <num> Set the minimal number of iterations used for the bal‐
ancing by the rubberband method to <num>. If an itera‐
tion of that method does not yield an improvment, the
method normally stops. But this situation might be a
local minimum of the quality of the layout, i.e. further
iterations might find a better layout. Thus, the mini‐
mal number of iterations can be specified. The default
value is 0.
-smax <num> Set the maximal number of iterations used for the
straight line tuning phase to <num>. This phase forces
straight long edges with gradient 90 degree. It can be
used to improve the priority layout or the manhattan
layout.
-nocopt | -nocopt2
Skip the optimization phase 2 during the crossing reduc‐
tion. This phase takes very long time on very large
graphs. Before reducing the number of iterations of the
crossing reduction phase (see option -cmax <num> ) you
should first try to skip this optimization phase 2.
-nocoptl | -nocoptlocal
Switch a local crossing optimization off. This phase
additionally examines pairs of edge polygons and tries
to unwind them. It slows down if the degree of the
nodes is large.
OPTIONS FOR THE DISTRIBUTION OF NODES
The quality of the layout is mainly influenced by the distribution of
the nodes into the hierarchy levels. Nodes of the same level will
appear in the same row. Since it depends on the application which
hierarchy is the best, there are different algorithms for this phase.
-d normal Normal distribution of nodes into the levels
(default). This algorithm is based on the calculation
of the strongly connected components.
-d dfs Depth first search distribution of nodes into the lev‐
els. This is the fastest method.
-d 0 | -d minbackward
Reduce the number of backward edges heuristically. If
the graph is acyclic, no backward edges will occur, i.e.
all edges point into the same direction.
-d + | -d maxdepth
Maximize the depth of the layout heuristically. It
should be used if the layout is too wide in x direction.
This algorithm is very fast.
-d - | -d mindepth
Minimize the depth of the layout heuristically. It
should be used if the layout is too wide in y direction.
This algorithm is very fast.
-d ++ | -d maxdepthslow
Maximize the depth of the layout heuristically. See
above. This algorithm is very slow, but may give better
results.
-d -- | -d mindepthslow
Minimize the depth of the layout heuristically. See
above. This algorithm is very slow, but may give better
results.
-d minindeg | -d minindegree
Prepare the nodes by sorting them according increasing
indegree (number of incoming edges). The nodes with the
minimal indegree come first. This may have various
effects on the layout.
-d maxindeg | -d maxindegree
Prepare the nodes by sorting them according decreasing
indegree. The nodes with the maximal indegree come
first. This may have various effects on the layout.
-d minoutdeg | -d minoutdegree
Prepare the nodes by sorting them according increasing
outdegree (number of outgoing edges). The nodes with
the minimal outdegree come first. This may have various
effects on the layout.
-d maxoutdeg | -d maxoutdegree
Prepare the nodes by sorting them according decreasing
outdegree. The nodes with the maximal outdegree come
first. This may have various effects on the layout.
-d mindeg | -d mindegree
Prepare the nodes by sorting them according increasing
degree (number of incoming and outgoing edges). The
nodes with the minimal degree come first. This may have
various effects on the layout.
-d maxdeg | -D maxdeg
Prepare the nodes by sorting them according decreasing
degree. The nodes with the maximal degree come first.
This may have various effects on the layout.
-d tree Use a specialized layout for trees. It does not work
with non-trees.
OPTIONS FOR THE VIEW
The view of a graph is the method of the visual appearance of the
graph in the window after the layout. Changing the view does not
require a relayout of the graph. Views are transformations that are
done during the drawing.
-view normal Normal view onto the graph. No distortion.
-view cfish Cartesian fisheye view. The graph is distorted such
that the whole graph is visible. Horizontal and verti‐
cal lines don't change their direction.
-view fcfish Cartesian fisheye view with fixed size focus. The graph
is distorted, but not necessarily the whole graph is
visible.
-view pfish Polar fisheye view. The graph is distorted such that
the whole graph is visible. Even horizontal and verti‐
cal lines might be distorted.
-view fpfish Polar fisheye view with fixed size focus. The graph
is distorted, but not necessarily the whole graph is
visible.
-spline Use splines instead of polygons to draw edges. This is
mainly useful if you want to export the graph into a
high quality PostScript picture. WARNING: Drawing
splines is very slow.
-nonodes Suppress drawing of nodes.
-noedges Suppress drawing of edges.
-xpos <num> Set the x-coordinate of the initial point of the graph
that appears at the window origin or of the initial
focus point to <num>.
-ypos <num> Set the y-coordinate of the initial point of the graph
that appears at the window origin or of the initial
focus point to <num>.
PRINTER DRIVER INTERFACE
The printer driver interface allows to produce an output file of the
visualized graph without the need of interaction. The VCG tool acts as
a kind of converter program in this case: it converts a VCG file into a
PostScript or bitmap file. It is recommended to use the option -silent
in combination to one of the options -vcgoutput, -psoutput, -pbmoutput,
or -ppmoutput. Example:
xvcg-silent -color -scale 75 -psoutput test.ps test.vcg
converts the VCG file test.vcg into a PostScript file that contains a
color picture of the graph scaled by 75 %. In this case the interac‐
tive display is suppressed. If the graph does not fit on the page, the
output might be nonsense.
PRINTER DRIVER OPTIONS-vcgoutput <filename>
Produce a VCG file named <filename> that contains the
graph laid out, i.e. including information about the co-
ordinates of the visible nodes. The most of the follow‐
ing format options have no effect for the VCG file for‐
mat.
-psoutput <filename>
Produce a PostScript file named <filename> that contains
the graph.
-pbmoutput <filename>
Produce a bitmap file named <filename> in PBM format
that contains the graph in black and white.
-ppmoutput <filename>
Produce a bitmap file named <filename> in PPM format
that contains the graph in colors.
-paper <papertype>
Select the paper type. Default is a4. <papertype> is
one of:
a4 din A4 (21 x 30 cm)
A4 din A4 (21 x 30 cm)
b5 din B5 (18.5 x 27 cm)
B5 din B5 (18.5 x 27 cm)
a5 din A5 (15 x 21 cm)
A5 din A5 (15 x 21 cm)
11x17 tabloid (11 x 17 in)
tabloid tabloid (11 x 17 in)
8x11 letter (8.5 x 11 in)
letter letter (8.5 x 11 in)
8x14 legal (8.5 x 14 in)
legal legal (8.5 x 14 in)
-noBoundingBox Suppress the calculation of a BoundingBox (PostScript
format).
-color Select a color file output. This option works only with
the PostScript format.
-grey Select a greyscaled file output. This option works only
with the PostScript format.
-blackwhite Select a monochromatic file output. This is the default
color. This option works only with the PostScript for‐
mat.
-portrait Select the paper orientation `Portrait' (default).
-landscape Select the paper orientation `Landscape'.
-split <num> Split the graph into <num> pages. This option works
only with the PostScript format. The number of pages
must be one of 1, 4, 9, 16, or 25.
-xdpi <num> Set the horizontal resolution for the PPM and PBM for‐
mat. This allows to adapt the bitmap formats to the
resolutions of the printer.
-ydpi <num> Set the vertical resolution for the PPM and PBM format.
This allows to adapt the bitmap formats to the resolu‐
tions of the printer.
-scale <num> Scale the graph to <num> percent for the file output.
The default scaling fits the graph with maximal aspect
ratio to the paper size.
-width <float> <units>
Fit the graph such that its width is smaller than
<float> <units>. This works only if no scaling is spec‐
ified. <units> are:
in Inches
inch Inches
ft Foot
foot Foot
feet Foot
mm Millimeter
cm Centimeter
dm Decimeter
m Meter
-height <float> <units>
Fit the graph such that its height is smaller than
<float> <units>. This works only if no scaling is spec‐
ified.
-lm <float> <units>
Set the left margin of the output to <float> <units>.
This works only if no right margin is specified. The
default position is centered on the page. In some cases
the BoundingBox of the PostScript output meight be
wrong. If a BoundingBox is needed then we recommend
the options -lm 0 cm -bm 0 cm.
-rm <float> <units>
Set the right margin of the output to <float> <units>.
This works only if no left margin is specified. The
default position is centered on the page.
-tm <float> <units>
Set the top margin of the output to <float> <units>.
This works only if no bottom margin is specified. The
default position is centered on the page.
-bm <float> <units>
Set the bottom margin of the output to <float> <units>.
This works only if no top margin is specified. The
default position is centered on the page.
X11 OPTIONS-display <host:dpy>
Set the remote X11 server to host:dpy. This is analo‐
gous to xterm(1l).
-geometry <geom>
Specify the hint of size and location of the X11 window.
This is analogous to xterm(1l).
-bw <num> Set the border width of the X11 window to <num> pixels.
This is analogous to xterm(1l).
-font <xfont> Set the font used for messages and menu items in the X11
window. This is analogous to xterm(1l).
-grabinputfocus
Switch setting of InputFocus on or off (depending on the
default). Cause the VCG tool to execute a XSetInputFo‐
cus, or to avoid to execute a XSetInputFocus on initial‐
ization.
GRAMMAR
The grammar of the specification language is the following:
graph
::= "graph:" '{' graph_entry_list '}'
;
graph_entry_list
::= graph_entry_list graph_entry
| graph_entry
;
graph_entry
::= graph_attribute
| node_defaults
| edge_defaults
| foldnode_defaults
| foldedge_defaults
| graph
| node
| edge
| nearedge
| bentnearedge
| backedge
;
graph_attribute
::= "title" ':' string
| "label" ':' string
| "info1" ':' string
| "info2" ':' string
| "info3" ':' string
| "color" ':' enum_color
| "textcolor" ':'enum_color
| "bordercolor" ':'enum_color
| "width" ':' integer
| "height" ':' integer
| "borderwidth" ':' integer
| 'x' ':' integer
| 'y' ':' integer
| "loc:" '{' 'x' ':' integer 'y' ':' integer '}'
| "folding" ':' integer
| "scaling" ':' float
| "shrink" ':' integer
| "stretch" ':' integer
| "textmode" ':' enum_textmode
| "shape" ':' enum_shape
| "level" ':' integer
| "vertical_order" ':' integer
| "horizontal_order" ':' integer
| "status" ':' enum_status
| "xmax" ':' integer
| "ymax" ':' integer
| "xbase" ':' integer
| "ybase" ':' integer
| "xspace" ':' integer
| "xlspace" ':' integer
| "yspace" ':' integer
| "xraster" ':' integer
| "xlraster" ':' integer
| "yraster" ':' integer
| "invisible" ':' integer
| "hidden" ':' integer
| "classname" integer ':' string
| "infoname" integer ':' string
| "colorentry" integer ':' integer integer integer
| "layoutalgorithm" ':' enum_layoutalgorithm
| "layout_downfactor" ':' integer
| "layout_upfactor" ':' integer
| "layout_nearfactor" ':' integer
| "splinefactor" ':' integer
| "late_edge_labels" ':' enum_yes_no
| "display_edge_labels" ':' enum_yes_no
| "dirty_edge_labels" ':' enum_yes_no
| "finetuning" ':' enum_yes_no
| "ignoresingles" ':' enum_yes_no
| "straight_phase" ':' enum_yes_no
| "priority_phase" ':' enum_yes_no
| "manhattan_edges" ':' enum_yes_no
| "smanhattan_edges" ':' enum_yes_no
| "nearedges" ':' enum_yes_no
| "orientation" ':' enum_orientation
| "node_alignment" ':' enum_node_align
| "port_sharing" ':' enum_yes_no
| "arrowmode" ':' enum_arrow_mode
| "spreadlevel" ':' integer
| "treefactor" ':' float
| "crossingphase2" ':' enum_yes_no
| "crossingoptimization" ':' enum_yes_no
| "crossingweight" ':' enum_cross_weight
| "view" ':' enum_view
| "edges" ':' enum_yes_no
| "nodes" ':' enum_yes_no
| "splines" ':' enum_yes_no
| "bmax" ':' integer
| "cmax" ':' integer
| "cmin" ':' integer
| "pmax" ':' integer
| "pmin" ':' integer
| "rmax" ':' integer
| "rmin" ':' integer
| "smax" ':' integer
;
enum_color
::= "aquamarine"
| "black"
| "blue"
| "cyan"
| "darkblue"
| "darkcyan"
| "darkgreen"
| "darkgrey"
| "darkmagenta"
| "darkred"
| "darkyellow"
| "gold"
| "green"
| "khaki"
| "lightblue"
| "lightcyan"
| "lightgreen"
| "lightgrey"
| "lightmagenta"
| "lightred"
| "lightyellow"
| "lilac"
| "magenta"
| "orange"
| "orchid"
| "pink"
| "purple"
| "red"
| "turquoise"
| "white"
| "yellow"
| "yellowgreen"
| integer
;
enum_orientation
::= "top_to_bottom"
| "bottom_to_top"
| "left_to_right"
| "right_to_left"
;
enum_layoutalgorithm
::=
| "tree"
| "maxdepth"
| "mindepth"
| "maxdepthslow"
| "mindepthslow"
| "maxdegree"
| "mindegree"
| "maxindegree"
| "minindegree"
| "maxoutdegree"
| "minoutdegree"
| "minbackward"
| "dfs"
;
enum_status
::= "black"
| "grey"
| "white"
;
enum_yes_no
::= "yes"
| "no"
;
enum_cross_weight
::= "bary"
| "median"
| "barymedian"
| "medianbary"
;
enum_view
::= "cfish"
| "fcfish"
| "pfish"
| "fpfish"
;
enum_arrow_mode
::= "fixed"
| "free"
;
foldnode_defaults
::= "foldnode." node_attribute
;
foldedge_defaults
::= "foldedge." edge_attribute
;
node_defaults
::= "node." node_attribute
;
edge_defaults
::= "edge." edge_attribute
;
node ::= "node:" '{' node_attribute_list '}'
;
node_attribute_list
::= node_attribute_list node_attribute
| node_attribute
;
edge ::= "edge:" '{' edge_attribute_list '}'
;
nearedge
::= "nearedge:" '{' edge_attribute_list '}'
;
bentnearedge
::= "bentnearedge:" '{' edge_attribute_list '}'
;
backedge
::= "backedge:" '{' edge_attribute_list '}'
;
edge_attribute_list
::= edge_attribute_list edge_attribute
| edge_attribute
;
node_attribute
::= "title" ':' string
| "label" ':' string
| "info1" ':' string
| "info2" ':' string
| "info3" ':' string
| "color" ':' enum_color
| "textcolor" ':'enum_color
| "bordercolor" ':'enum_color
| "width" ':' integer
| "height" ':' integer
| "borderwidth" ':' integer
| "loc:" '{' 'x' ':' integer 'y' ':' integer '}'
| "folding" ':' integer
| "scaling" ':' float
| "shrink" ':' integer
| "stretch" ':' integer
| "textmode" ':' enum_textmode
| "shape" ':' enum_shape
| "level" ':' integer
| "vertical_order" ':' integer
| "horizontal_order" ':' integer
;
enum_textmode
::= "center"
| "left_justify"
| "right_justify"
;
enum_shape
::= "box"
| "rhomb"
| "ellipse"
| "triangle"
;
enum_node_align
::= "bottom"
| "top"
| "center"
;
edge_attribute
::= "sourcename" ':' string
| "targetname" ':' string
| "label" ':' string
| "textcolor" ':'enum_color
| "color" ':' enum_color
| "thickness" ':' integer
| "class" ':' integer
| "priority" ':' integer
| "arrowcolor" ':' enum_color
| "backarrowcolor" ':' enum_color
| "arrowsize" ':' integer
| "backarrowsize" ':' integer
| "arrowstyle" ':' enum_arrowstyle
| "backarrowstyle" ':' enum_arrowstyle
| "linestyle" ':' enum_linestyle
| "anchor" ':' integer
| "horizontal_order" ':' integer
;
enum_linestyle
::= "continuous"
| "solid"
| "dotted"
| "dashed"
| "invisible"
;
enum_arrowstyle
::= none
| line
| solid
;
WARNINGS
The VCG tool needs about 200 bytes per edge and node. Depending on the
layout, it will produce a lot of additional dummy nodes and dummy
edges, such that it may run out of memory. The layout algorithm needs
exponentially time in the worst case.
ACKNOWLEDGEMENTS
The Edge tool was developed at the University of Karlsruhe. GRL was
described by S. Manke and F.N. Paulisch.
Our colleagues M. Alt and C. Ferdinand found the most bugs and gave
many proposals for improvements.
The Institute of Compiler Construction at the University of Saarland,
Germany, and the COMPARE Consortium were the first and most important
users of the VCG tool and gave us the motivation, the time and many
hints during the development of the tool.
SEE ALSOSunview(1)X11(1l)edge(l)vcgdemomaker(l)pbmshift(l)pbmrot90(l)pbm2hp(l)
VCG - Visualization of Compiler Graphs, Design Report and User Documen‐
tation, Ref. Compare, USAAR-1049-visual, January 1994, updated January
1995
BUGS
The X11 version has the `InputFocus' problem. This problem is solved
for 99 % of all cases, but may still occur.
If a graph is written to a file and reload from this file, the layout
may be different and may be ugly.
The attribute horizontal_order does only works for connected graphs,
but not for unconnected graphs.
For some parameters, negative values are inappropriate even if the tool
does not crashes in such situations. However the result will be very
ugly. For instance, the values of xbase and ybase should always be
greater than zero.
The spline routine is still too slow and has some bugs when exporting
to a multi page PostScript file.
Currently, no further bugs are known.
AUTHORS
Georg Sander, University of Saarland, Germany.
Iris Lemke, University of Saarland, Germany.
Release 1.3 1995/01/05 VCG | XVCG(1l)
