Jgraph


Jgraph is a tool for drawing graphs and structured drawings. Unlike most drawing tools, jgraph is non-interactive -- its takes an input file, and produces either plain or encapsulated PostScript as output. Encapsulated PostScript is a format that many text processing programs, like LaTeX, use for figures. Many printers will print PostScript. And, there are programs to convert PostScript to other formats. Most Unix installations have the program ps2pdf, which converts to PDF. Once you have PDF, there are loads of programs to convert to any format you want.

You run jgraph with

jgraph [-PL] [input-file]

If you don't specify a file, it will read from standard input. It will emit encapsulated PostScript on standard output. If you specify -P, then it will emit non-encapsulated PostScript that can go to a printer. If you want to get PDF from a jgraph, typically use the -P option and then pipe the output to "ps2pdf -". If you then want JPEG, pipe that to convert - output.jpg.

The complete reference for jgraph is its man page. The nroff is in ~plank/src/jgraph/jgraph.1. Here's a link to the formatted manual. There's a nice man page online at https://manpages.debian.org/jessie/jgraph/jgraph.1.en.html.


Simple Jgraph Examples

As with most programs, it's easiest to get conversant with jgraph by looking at examples. With jgraph, you specify to draw a new graph with the newgraph keyword. You can then add curves to your graph with newcurve, and points to your curve with pts. Below is a simple example, in (in simp1.jgr). I'll convert it to JPEG with:
UNIX> jgraph -P simp1.jgr | ps2pdf - | convert -density 300 - -quality 100 simp1.jpg
Here is the jgraph and the JPEG (which I cropped manually):

(* Simple jgraph *)

newgraph

newcurve pts 2 3   4 5   1 6

What this has done is draw a simple graph with three points: (2,3), (4,5) and (1,6). Jgraph added axes and chose how to plot the points. It's not very pretty, but it's a start.

Next, take a look at simp2.jgr and its output:

newgraph
xaxis size 2 
yaxis size 1.5 

newcurve pts 0 6  1 9  2 11  3 14  4 18 5 20
newcurve marktype triangle linetype solid 
         pts 0 3  1 4  2 7  3 9  4 10 5 13
newcurve marktype none linetype dashed color 1 0 0
         pts 0 0  1 2  2 3  3 5  4 6  5 9

The second two lines set the sizes of the x and y axes to 2 inches and 1.5 inches repectively (the JPG in the drawing blows it up - if you simply look at the PDF, it will be the correct size).

We then plot three curves: The first curve lets jgraph choose the drawing style. The second plots the points with triangles, and connects them with a solid line. The third does not plot the points, but just the line connecting them. The line is dashed, and its color will be red (colors are specified as rgb values where 1 is full saturation, so "1 0 0" is all red, no green and no blue). You'll note that the axes have been made big enough to hold all of the points. That is the default behavior.

The valid marktypes and linetypes are defined in the man page. You may use newline instead of ``newcurve marktype none linetype solid''


Some Syntax

Jgraph is not line based. It simply works on words separated by white space. Comments must be surrounded by (* and *). There are a few basic objects in jgraph: You may view jgraph input as editing these objects. Thus, when you say newcurve you are then editing a curve, and may specify curve attributes like the marktype, linetype and points. Most attributes have defaults which you can change. If you specify an attribute more than once, jgraph will only honor the last one, so saying ``newcurve marktype box marktype circle'' is equivalent to ``newcurve marktype circle.''

There are some exceptions to this. For example, whenever you say pts, you are adding points to the current curve. Therefore

newcurve pts 0 0   1 1   2 2 
and
newcurve pts 0 0 pts 1 1 pts 2 2
are equivalent.

You may include files most anywhere in your jgraph input by saying ``include filename.''


Messing with the axes

Often you don't like the way that jgraph automatically lays out axes. Axes have the following attributes (among others): Below is axis.jgr, and the graph it produces:

newgraph

xaxis 
  min 0 max 100
  hash 15 
  mhash 2 (* i.e. minor hashes at the 5's and 10's *)
  color 1 0 0
  label : This is the X axis
  draw_at 10

yaxis 
  min 1 max 1000
  log
  no_draw_hash_marks
  label : And this is the Y axis
  color 0 0 .75

newline color 1 0 1 
  pts 10 1 
      20 5 
      30 10 
      40 20 
      50 100 
      60 110 
      70 500 
      80 800 
      90 1000
      100 1


Messing with curves

Jgraph chooses default sizes for your marks. You may set them yourself with marksize width height. The width will be units of the x axis (or inches if the axis is logarithmic), and the height will be in units of the y axis.

You may say copycurve to create a curve with the same attributes as the previous curve (but not the same points).

Below, curve.jgr shows an example. Note that cfill fills the inside of a mark with the specified color. You can change all of the mark's color with color, and you can use fill to specify grayscale. You can specify none as a fill value, and the mark will be empty (transparent).

newgraph

xaxis min 0 max 9 
yaxis min 0 max 10 

newcurve marktype box marksize 1.5 1 
         linetype solid cfill 1 0 0
   pts 1 3  2 5  3 1  4 8

copycurve marktype ellipse cfill 1 0 .5
   pts 6 3  7 5  8 1  9 8


Strings

Jgraph lets you plot strings with newstring. String attributes are the location font, fontsize, color, rotation justification and the text. The location is set by ``x x-position y y-position.'' The font must be a postscript font. Standard fonts are Times-Roman, Times-Italic, Times-Bold, Helvetica, Helvetica-Italic, Helvetica-Bold, Courier, and Symbol.

The color is specified with lcolor (lgray lets you specify greyscale). Justifications are specified as follows:

You can rotate a string with rotate deg. You set the text of the string with a colon, followed by either a space or a newline, and then the text. If you want multiline text, then end all lines but the last with a backslash.

Graph labels are strings too and can make use of the above attributes.

Copystring copies all attributes of a string (including the text).

newgraph
  xaxis min 0 max 10 hash 1 mhash 0 size 5
  yaxis min 0 max 8 hash 1 mhash 0 size 5
        grid_lines grid_gray .7

newstring hjl vjc x 1 y 1 : String #1

newstring hjr vjt x 9 y 1 
          fontsize 20 lcolor 1 0 0 : String #2

copystring hjl vjb x 1 y 2 
          fontsize 16 font Times-Italic : String #3

newstring hjr vjt x 9 y 2 
          fontsize 16 font Helvetica : String #4

newstring hjc vjc x 5 y 2 
          fontsize 16 font Symbol : String #5

newstring hjl vjb fontsize 45 
          font Courier rotate 90 x 5 y 2.5 : String #6


Legends

You can add a label to a curve with the label attribute. This specifies to make a legend entry for the curve. See legend1.jgr for an example:

newgraph
xaxis min 0 max 5 
yaxis min 0 size 2 nodraw

newcurve marktype box linetype solid label : Line number one
   pts 0 6  1 9  2 11  3 14  4 18 5 20
newcurve marktype triangle linetype dashed color 1 0 0 label : Line number two
   pts 0 3  1 4  2 7  3 9  4 10 5 13
newcurve marktype none linetype dotdotdash color 1 0 1 label : And number three
         pts 0 0  1 2  2 3  3 5  4 6  5 9

You can change the font and location of the legend as a unit by saying ``legend defaults'' and then specifying string attributes. This will modify all of the legend strings. See legend2.jgr for an example. Try modifying it and see what happens. There are other cool things you can do with the legend -- see the man page.

newgraph
xaxis min 0 max 5 
yaxis min 0 size 2 nodraw 

newcurve marktype box linetype solid label : Line number one
   pts 0 6  1 9  2 11  3 14  4 18 5 20
newcurve marktype triangle linetype dashed color 1 0 0 label : Line number two
   pts 0 3  1 4  2 7  3 9  4 10 5 13
newcurve marktype none linetype dotdotdash color 1 0 1 label : And number three
         pts 0 0  1 2  2 3  3 5  4 6  5 9

legend defaults font Times-Italic fontsize 20 rotate 30 hjl vjt x 6 y 0


Hash_Labels

Like the legend defaults, you may modify the hash labels on an axis as a composite, using the ``hash_labels'' attribute. Below is a graph that does the following additional things:

newgraph

(* Set up the x axis to have three points. 
   Give it a little extra room to the right and left.
   The shash says to line up the hash marks so that
   if zero were on the axis, there would be a hash
   mark at zero. *)

xaxis size 1 min .8 max 3.2 hash 1 mhash 0 shash 0

    (* Don't produce hash labels automatically, but
       instead put three custom labels at hash marks
       1, 2 and 3. *)
    no_auto_hash_labels          
    hash_label at 1 : Kilobyte
    hash_label at 2 : Megabyte
    hash_label at 3 : Gigabyte

    (* This sets the font and font size of the labels, it also
       says to left/center justify them and rotate them down 
       60 degrees. *)

    hash_labels fontsize 12 font Times-Italic hjl vjc rotate -60

(* The y axis is more standard. *)

yaxis size 2 min 0 max 15 hash 5 mhash 4

  (* However, we're adding a labeled hash mark at 13.5 *)

  hash_at 13.5 hash_label at 13.5 : Control

  hash_labels fontsize 12    (* And we're setting the font size to 12 *)
  grid_lines grid_gray .7    (* And drawing grid lines at a grey level of 0.7 *)

(* Draw a reference line at y=13.5 through the whole graph *)

newline pts 0.8 13.5 3.2 13.5

(* And draw a red curve with red boxes and a doubly thick line *)

newcurve marktype box color 1 0 0 
         linetype solid color 1 0 0 
         linethickness 2
   pts 1 8  2 11  3 15


Bar Graphs

You may use the xbar and ybar marktypes to make bar graphs. Xbar means draw the bar to the x-axis, and ybar means draw the bar to the y-axis.

The file bar.jgr shows a straightforward example.

newgraph

(* Set up the x axis to have some 
   extra room to the right and left. *)

xaxis size 2
  min 0.1 max 10.9 hash 1 mhash 0 shash 0
  label : Words

(* Nothing exciting here about the x axis *)

yaxis min 0 max 100 size 2
  label : Speed (GB/s)
  grid_lines grid_gray .7

(* Put the legend at the top *)

legend top 

(* Unfortunately, if you don't do this, the
   x axis will be gray. *)

newline pts 0.1 0 10.9 0

(* The bars are filled with yellow *)

newcurve marktype xbar cfill 1 1 0

  (* The mark size says a width of 0.8,
     and in the legend, it has a height of
     five.  The units are the units of the
     x and y axes. *)

  marksize .8 5 cfill 1 1 0

  label : These are random bars
  pts 
   1 80.7677 2 28.498 3 72.8278
   4 49.3617 5 92.705 6 84.8035
   7 47.2454 8 46.721 9 25.5328 10 64.1393


Fancier things: polygons

Jgraph lets you turn curves into polygons, which helps when you start using jgraph to make drawings. Simply use the poly attribute for the curve. Pfill and pcfill allow you to specify greyscale and color filling for the polygon. linethickness lets you control the thickness of the border line. The units of linethickness are ``absolute postscript units'' -- the default is 1.0. You can fill the polygon with stripes rather than solid color by using ``ppattern stripe slant,'' where slant controls the degree of slanting. Finally, if you use -1 as a fill color, the polygon will just consist of the border -- the inside will not be filled. Sometimes this is desirable.

Poly.jgr shows an example of some polygons with different fillings. Note that jgraph draws curves in the order specified, so that you know how the overlapping will occur. Take a look at the output.

newgraph

xaxis min 0 max 10 size 5 hash_labels fontsize 16
yaxis min 0 max 10 size 5 hash_labels fontsize 16

(* Draw a red trapezoid -- setting both the fill and color to be red means
   that the entire trapezoid, and not just the interior, will be red. *)

newline poly pcfill 1 0 0 color 1 0 0
   pts 1 1  3 1   2.5 2  1.5 2

(* Draw a big black square *)

newline poly pfill 0 pts 3 3  10 3  10 10  3 10

(* Draw a thick yellow triangle with a purple, striped interior inside the black
   square *)

newline poly linethickness 5 color 1 1 0 pcfill 1 0 1 ppattern stripe 60 
   pts  4 4   8 4  6 6 

(* Draw a blue triangle with a thick border no fill *)

newline poly linethickness 10 color 0 0 1 pfill -1 pts 4 9  6 5 8 8 


Bezier curves

You can produce curved lines in jgraph by having the points specify control points on a bezier curve. I don't have the time to explain what bezier curves are, but each curve has 4 control points.

With jgraph you can use 3n+1 points to draw n connected bezier curves. The file football.jgr shows an example of drawing a low budget football using bezier curves in jgraph: I emphasize "low budget," but it works.

newgraph 
xaxis min 0 max 10 nodraw
yaxis min 0 max 10 nodraw

(* Draw the outline of the football *)

newline bezier poly pcfill .543 .270 .074 pts
  0 5   3 10   7 10    10 5
        7 0    3 0     0 5

(* Draw the main thread *)

newline bezier linethickness 4 gray 1 pts
  3 7 4.5 8 5.5 8 7 7

(* Draw the crossthreads *)

copycurve nobezier pts 3.5 6.7 3.3 7.5
copycurve pts 6.5 6.7 6.7 7.5
copycurve pts 4.2 7.1 4.1 7.9
copycurve pts 5.8 7.1 5.9 7.9
copycurve pts 5 7.3  5 8.1


The Shell

You can put shell commands into jgraph with
shell : command
This is a very powerful feature, becuase it lets you use shell scripts and scripting languages like awk to do function plotting, data extraction, etc.

For example, suppose you want to see what an n-squared curve looks like. Don't use some stupid Python script -- use Jgraph and Awk (in shell.jgr):

newgraph
xaxis min 0 max 3 hash 1 mhash 0 size 1
yaxis min 0 max 9 size 3 hash 1 mhash 0

newline pts
  shell : echo "" | awk '{ for (i = 0; i <= 3.05; i += .1) print i, i*i }'

For multi-line shell scripts (or labels, for that matter), simply put a backslash at the end of the line. Sometimes you'll have to put a semi-colon at the end of the line too, because it passes the backslash to the shell process.

Below, I have a typical usage of jgraph and the shell to do data extraction. This comes from the Floyd-Warshall lecture notes. I have all of my program timings in the file ap-timings.txt. Here are the first seven lines:

FW 64 4096 0.005
DIJKSTRA 64 4096 0.009
SIMD 64 4096 0.003
FW 128 16384 0.012
DIJKSTRA 128 16384 0.028
SIMD 128 16384 0.003
FW 192 36864 0.032

The format of the file is:

Label number-of-nodes elements-in-adjacency-matrix time-in-seconds

Below is the jgraph file that plots nodes vs time (in Floyd.jgr):

(* Nothing fancy with any of the axes. 
   I probably should specify a max for 
   the y-axis, but the graph looks fine
   without it. *)

newgraph
xaxis min 0 max 960 size 7
  hash 160 
  hash_labels fontsize 14
  label fontsize 18 : Nodes

yaxis min 0 size 5
  hash_labels fontsize 14
  label fontsize 18 : Time (seconds)

(* Put the legend into the upper-left hand
   corner of the graph *)

legend defaults hjl vjt x 25 y 3.00 fontsize 14  

(* For each of the three curves, grab the data from
   the file ap-timings.txt.  The x values are the
   second words on each line, and the y values are 
   the last words.  Each line is labeled on its first
   word, and I use grep to isolate lines with the
   labels that I want. *)

newline marktype circle color 0 0 0 
pts 
  shell : grep FW ap-timings.txt | awk '{ print $2, $NF }'
  label : Floyd-Warshall, the original implementation

newline marktype circle color 1 0 0 
pts 
  shell : grep DIJKSTRA ap-timings.txt | awk '{ print $2, $NF }'
  label : Dijsktra

newline marktype circle color .5 0 .5 
pts 
  shell : grep SIMD ap-timings.txt | awk '{ print $2, $NF }'
  label : Floyd-Warshall - SIMD


Postscript marks

One of the neat features of jgraph is the ability to use an encapsulated postscript file as a marktype. For example, we can use the football above as a mark to make one of those USA Today-style graphs. First, we make football.eps using jgraph without the -P option.
UNIX> jgraph football.jgr > football.eps
Now, we'll draw a USA Today style graph. It's in fbf.jgr -- read the comments for explanation. You'll note that there are multiline labels, and multiline shell scripts in the file:

newgraph

(* Set up a "graph" to be a football field.
   There will be two points on the X axis, one
   for the University of Tennessee, and one
   for Princeton. That's why we use
   no_auto_hash_labels *)

xaxis 
  min .2 max 2.8 size 5
  no_auto_hash_labels mhash 0 hash 1 shash 1

(* The Y axis has no labels. *)

yaxis 
  min 0 max 10 size 6 
  nodraw

(* Draw the football field.as one big green mark. *)

newcurve marktype box marksize 2.6 10 cfill 0 .5 0 pts 1.5 5

(* Draw 10-yard lines as two lines with a gap in the middle for
   the yard number. *)

shell : echo "" | awk '{ \
          for (i = 1; i < 10; i += 1) { \
             printf ("newline gray 1 pts 0.2 %d 1.4 %d\n", i, i); \
             printf ("newline gray 1 pts 1.6 %d 2.8 %d\n", i, i); \
          } }'

(* Draw 10-yard labels.  I do this by specifying a string which I
   never draw, and then copying it. *)

newstring hjc vjc font Times-Italic lgray 1 fontsize 14 x 1.5

shell : echo "" | awk '{ \
          for (i = 1; i < 6; i += 1) { \
             printf "copystring y %d : %d0\n",i, i \
          } }'
         
shell : echo "" | awk '{ \
          for (i = 6; i < 10; i += 1) { \
             printf "copystring y %d : %d0\n",i, 10-i \
          } }'
         
(* Draw 1-yard marks *)

shell : echo "" | awk '{ \
          for (i = 0; i < 10; i += .1) { \
             printf "newline gray 1 pts 0.97 %f 1.03 %f\n", i, i; \
             printf "newline gray 1 pts 1.97 %f 2.03 %f\n", i, i; \
          } }'
         
(* Now, draw footballs *)

newcurve eps football.eps marksize .35 1 pts
  shell : echo "" | awk '{ for (i = 0; i < 10; i++) printf "1, %.1f\n", i+.5 }'
  2 .5

(* Draw team names *)

xaxis
hash_labels fontsize 20
hash_label at 1 : University of\
Tennessee

hash_label at 2 : Princeton
 
(* Draw the label, and make a football legend by hand,
   without using the legend feature of jgraph *)

newstring fontsize 28 hjc vjt x 3.4 y 9
  : University\
Football\
Budgets

newcurve eps football.eps marksize .35 1 pts 3.35 3

newstring fontsize 20 hjl vjc x 3.55 y 3 : =
copystring hjc vjc x 3.4 y 2 : 1 Gazillion\
Dollars


Other resources

There is more information about jgraph, and examples, at http://www.cs.utk.edu/~plank/plank/jgraph/jgraph.html.

Multiple Graphs

You can put multiple graphs in one drawing with another newgraph or with a copygraph, to copy the axes of a previous graph. X_translate and y_translate are two attributes of graphs that let you lay out multiple graphs. You can also put graphs on multiple pages with newpage.

The file copygraph.jgr shows a very simple example of using copygraph to make two very similar graphs side-by-side:

(* copygraph.jgr *)

newgraph
xaxis min 0 max 10 size 1 label fontsize 16 font Times-Italic : Graph 1
yaxis min 0 max 10 size 1

newcurve marktype box linetype solid pts 1 10 2 8 5 5 8 3 10 2

(* I copy the graph and change the x axis label.
   x_translate 2 says to translate this graph two inches
   horizontally.  You can put negative numbers there as well. *)

copygraph 
x_translate 2
xaxis label : Graph 2
newcurve marktype box linetype solid pts 10 10 8 8 5 5 8 3 10 2


If I get bored, I'll go over creating the heatmap graph from the min-hash lecture notes.