There is a difference, besides the use of PR instead of PA, as Ron pointed out. (I believe both are supported, in each language. The substitution of smeicolons for carriage returns is common, also.) If you look closely, you will see that the order of the arguments coordinates, for the most part) and commands are different. HPGL, like PostScript, is what is called a "Reverse Polish Notation" language, in which the arguments are written *before* the command, rather than after.
All these variants are vector languages, again like PostScript, and can support drawing curves, lines, lettering, etc. as finely as you want. The difficulty is finding a single format that can be written and read by all of the tools we want to use. Dave On Sat, 8 Apr 2000, Ron Anthony wrote: > > To me it appears that the two files are similar. When I look at the two > files I see the same types of commands except the HPGL commands are > separated by semicolon. > > The PA command is PLOT ABOSULTE which means to move the pen to an absolute > x.y coordinate. A line is drawn if the pen is down. PR being PLOT > RELATIVE from when the pen is. > > My guess is that HPGL is an extension of older HP plotter languages. > ++ron > > ----- Original Message ----- > From: Robert Terwilliger <[EMAIL PROTECTED]> > > > Here is a snip from a HPGL file. The commands "PU" and "PD" stand for > > "Pen Up" and "Pen Down" respectively. It would be logical that "PA" > > stands for "Pen Advance" followed by the XY coordinates. > > > > PU;PA 3486, 5524; > > PD;PA 8344, 6729; > > PU;PA 8344, 1911; > > PD;PA 8344, 6729; > > PU;PA 3486, 706; > > PD;PA 20, 1399; > > > > Here is a snip from a prn file produced by printing a DeltaCad drawing > > to a HP plotter on File. The format is completely different. > > > > > 370,2005PRPD55,0PAPU-345,2000PRPD-50,0PAPU-370,1995PRPD-55,0PAPU-400,1990PRP > D-50,0PAPU-425,1985PRPD-55,0,0,-5,30,0PAPU-475,1975PRPD-5,0PAPAPU-470,1985PR > PD-5,0,5,-5,-20,0PAPU-510,1975PRPD40,0PAPU-490,1970PRPD-35,0PAPU-510,1965PRP > D-35,0PAPU-560,1960PRPD35,0PAPU-545,1955PRPD-35,0PAPU-595,1950PRPD35,0PAPU-5 > 80,1945PRPD-35,0PAPU-595,1940PRPD-40,0,0,-5,20,0PAPU-630,1930PRPD-5,0PAPAPU-
