-dpng gives "invalid command"

[John B. Thoo]

On Jul 10, 2009, at 10:56 AM, Ben Abbott wrote:

> On Friday, July 10, 2009, at 12:37PM, "John B. Thoo"  
> <jthoo at yccd.edu> wrote:
>> Hi, everyone.
>>
>> I can save a plot to EPS by
>>
>>   print ("foo.eps", "-deps")
>>
>> but when I try to save a plot to PNG by
>>
>>   print ("foo.png", "-dpng")
>>
>> I get a run of errors like
>>
>>
>> gnuplot> e
>>          ^
>>          line 0: invalid command
>>
>>
>> and no plot is saved.
>>
>> What am I doing wrongly?
>>
>> I'm using Octave 3.0.5 and gnuplot 4.2 patchlevel 5 in an X11 xterm
>> window in Mac OS X 10.4.11.
>>
>> Thanks.
>>
>
> I have no problem producing png output with 3.2 and gnuplot 4.2.5.
>
> Can you run gnuplot and try ...
>
>     set term png
>     set output foo.png
>     plot sin(x)
>     quit
>
> Do you still get the error?

Hi, Ben.  When I open gnuplot separately from Octave and try to "set  
term png", I get this error:


[533] bash-2.05b$ gnuplot

         G N U P L O T
         Version 4.2 patchlevel 5
         last modified Mar 2009
         System: Darwin 8.11.0

         Copyright (C) 1986 - 1993, 1998, 2004, 2007 - 2009
         Thomas Williams, Colin Kelley and many others

         Type `help` to access the on-line reference manual.
         The gnuplot FAQ is available from http://www.gnuplot.info/faq/

         Send bug reports and suggestions to <http://sourceforge.net/ 
projects/gnuplot>


Terminal type set to 'aqua'
gnuplot> set term png
                   ^
          unknown or ambiguous terminal type; type just 'set  
terminal' for a list

gnuplot>


When I type just "set terminal" for a list of available terminals  
types, I get:

Available terminal types:
            aed512  AED 512 Terminal
            aed767  AED 767 Terminal
              aifm  Adobe Illustrator 3.0 Format
              aqua  Interface to graphics terminal server for Mac OS X
          bitgraph  BBN Bitgraph Terminal
               cgm  Computer Graphics Metafile
             corel  EPS format for CorelDRAW
              dumb  ascii art for anything that prints text
               dxf  dxf-file for AutoCad (default size 120x80)
             eepic  EEPIC -- extended LaTeX picture environment
               emf  Enhanced Metafile format
             emtex  LaTeX picture environment with emTeX specials
          epslatex  LaTeX picture environment using graphicx package
      epson_180dpi  Epson LQ-style 180-dot per inch (24 pin) printers
       epson_60dpi  Epson-style 60-dot per inch printers
       epson_lx800  Epson LX-800, Star NL-10, NX-1000, PROPRINTER ...
               fig  FIG graphics language for XFIG graphics editor
              gpic  GPIC -- Produce graphs in groff using the gpic  
preprocessor
           hp2623A  HP2623A and maybe others
            hp2648  HP2648 and HP2647
            hp500c  HP DeskJet 500c, [75 100 150 300] [rle tiff]
              hpdj  HP DeskJet 500, [75 100 150 300]
              hpgl  HP7475 and relatives [number of pens] [eject]
            hpljii  HP Laserjet series II, [75 100 150 300]
              hppj  HP PaintJet and HP3630 [FNT5X9 FNT9X17 FNT13X25]
            imagen  Imagen laser printer
        kc_tek40xx  MS-DOS Kermit Tek4010 terminal emulator - color
        km_tek40xx  MS-DOS Kermit Tek4010 terminal emulator - monochrome
             latex  LaTeX picture environment
                mf  Metafont plotting standard
               mif  Frame maker MIF 3.00 format
                mp  MetaPost plotting standard
           nec_cp6  NEC printer CP6, Epson LQ-800 [monocrome color  
draft]
           okidata  OKIDATA 320/321 Standard
               pbm  Portable bitmap [small medium large] [monochrome  
gray color]
              pcl5  HP Designjet 750C, HP Laserjet III/IV, etc. (many  
options)
        postscript  PostScript graphics, including EPSF embedded  
files (*.eps)
           pslatex  LaTeX picture environment with PostScript \specials
             pstex  plain TeX with PostScript \specials
          pstricks  LaTeX picture environment with PSTricks macros
               qms  QMS/QUIC Laser printer (also Talaris 1200 and  
others)
             regis  REGIS graphics language
           selanar  Selanar
             starc  Star Color Printer
               svg  W3C Scalable Vector Graphics driver
       tandy_60dpi  Tandy DMP-130 series 60-dot per inch graphics
           tek40xx  Tektronix 4010 and others; most TEK emulators
           tek410x  Tektronix 4106, 4107, 4109 and 420X terminals
           texdraw  LaTeX texdraw environment
              tgif  TGIF X11 [mode] [x,y] [dashed] ["font" [fontsize]]
          tkcanvas  Tk/Tcl canvas widget [perltk] [interactive]
              tpic  TPIC -- LaTeX picture environment with tpic  
\specials
           unknown  Unknown terminal type - not a plotting device
             vttek  VT-like tek40xx terminal emulator
               x11  X11 Window System
              xlib  X11 Window System (gnulib_x11 dump)
(END)


so I see that png is not on the list.  (No "gif" either.)  Hmm ... I  
guess that explains it.   What do you suggest I do?

Thanks.

---John.