How can I cross out a node in Graphviz? - graphviz

Question

I would like to indicate that a node should be there, but is currently lacking in the process.
Intuitively I would like to cross it out as shown in below image (now done manually in Paint):
Is there a node attribute in Graphviz that I can use for this?

Answer 1

I can't find an attribute or node shape to do what you want, but here are two ways to do it:
build an image outside of Graphviz (with the text and the X) and use the image attribute to use the image as the node (yes, a pain if you want to do this frequently):
b [image="myB.png"]
For every X'd out node, add 2 new edges from .ne to .sw and .nw to .se (see below) Each with this (new) attribute: straightline=1. Then run this command:
dot -Tdot Xout2.gv |gvpr -f straightline.gvpr -c | neato -n2 -Tpng >out.png
Where this is straightline.gvpr:
E[straightline==1]{
int i, n;
string pt[int];
double x1, y1, x2, y2, xI1, yI1, xI2, yI2;
n=split($.pos, pt, " ");
for (i=0;i<=1;i++){
if (match(pt[i],"e,")>=0){
print ("// BEFORE: ", pt[i]);
pt[n-1]=substr(pt[i],2);
print ("// AFTER: ", pt[i]);
pt[i]=pt[i+1];
}
}
for (i=0;i<=1;i++){
if (match(pt[i],"s,")>=0){
pt[0]=substr(pt[i],2);
}
}
sscanf (pt[0], "%f,%f", &x1, &y1);
sscanf (pt[n-1], "%f,%f", &x2, &y2);
xI1=x1+(x2-x1)*.3;
yI1=y1+(y2-y1)*.3;
xI2=x1+(x2-x1)*.7;
yI2=y1+(y2-y1)*.7;
$.pos=sprintf("%s %.3f,%.3f %.3f,%.3f %s", pt[0], xI1, yI1, xI2, yI2, pt[n-1]);
}
From this input:
digraph X{
graph [outputorder=edgefirst]
b [ label="X me"]
a -> b -> c
a -> d
d -> c
e -> f
g -> i -> k
edge [color="#ff000080" penwidth=2] // note translucent color
b:ne -> b:sw [straightline=1]
b:se -> b:nw [straightline=1]
edge [color="green" penwidth=2]
e:n -> e:s [straightline=1]
f:w -> f:se [straightline=1]
edge [color="orange" penwidth=2]
g:n -> g:se [dir=back straightline=1]
edge [color="blue" penwidth=2]
g:n -> g:sw [dir=back straightline=1]
i:e -> i:w [dir=none straightline=1]
k -> k:s [dir=both straightline=1]
}
Sorry, convoluted, but it works.

Answer 2

While the answer of sroush gives me the exact output I need, it requires that I understand how to introduce gvpr in my workflow which will take a bit of time.
In the meantime I came up with a dot only approach, which approximates crossing out a node sufficiently for my purpose.
In below graph I would like to cross out the node Some process:
digraph graphname {
rankdir=LR
node [fillcolor="lightblue3", style="filled"]
a
c
d
b [label="Some\nprocess"]
a -> b -> c
a -> d -> c
{rank=same a;d}
}
To do so I change:
the nodestyle of the Some process node to have a diagonal hard gradient
use a HTML-like label to strikethrough the text
Make the fontcolor and node outline a shade of gray
digraph graphname {
rankdir=LR
node [fillcolor="lightblue3", style="filled"]
a
c
d
node [fillcolor="lightblue3;0.5:white", style="filled", fontcolor="gray50", color="gray50", gradientangle=100]
b [label=<<s>Some<br/>process</s>>]
a -> b -> c
a -> d -> c
{rank=same a;d}
}