Example plot in Manual lacks text

[Michael D. Godfrey]

In the current 3.1.55 development doc/octave.pdf, pg. 248
Figure 15.7 the text is missing.  Looking at the files in
doc/interpreter I found that the source files are:

extended.eps     contains text
extended.pdf      contains text
extended.png     text is missing

I conclude that "extended.png" was used to produce the Manual.
And, when running a .m file containing the commands shown in
the manual, I get:

octave:1> fig157
octave:2> print("fig157.png","-color")
gdImageStringFT: Could not find/open font while printing string ¬ 
with font Symbol
gdImageStringFT: Could not find/open font while printing string  x =  
with font
gdImageStringFT: Could not find/open font while printing string 2/ with 
font
gdImageStringFT: Could not find/open font while printing string Ö 
with font Symbol
gdImageStringFT: Could not find/open font while printing string p with 
font Symbol
gdImageStringFT: Could not find/open font while printing string   with font
gdImageStringFT: Could not find/open font while printing string ò 
with font Symbol
gdImageStringFT: Could not find/open font while printing string 0 with font
gdImageStringFT: Could not find/open font while printing string x with font
gdImageStringFT: Could not find/open font while printing string  e with 
font
gdImageStringFT: Could not find/open font while printing string -t with 
font
gdImageStringFT: Could not find/open font while printing string 2 with font
gdImageStringFT: Could not find/open font while printing string  dt with 
font
gdImageStringFT: Could not find/open font while printing string  = 
0.6175 with font

================================================================
These messages also appear in the make output.

In any case, would it not be better to use the *.eps files for 
generating the Manual?
I think that most users include .eps in their documents.  (Or, at least, 
that is what I see
around here.)

Michael Godfrey