MARSH@NCSUSTAT.BITNET (02/08/90)
A bit more followup on using the HP LaserJet as a plotter: Phil Miller sent in a query regarding the time to produce a complex plot that had lots of solids. He went on to relate that in his experience using a HP LaserJet in a PGL (the language of HP bed plotters) emulation mode that the speed of the HPLJ is a nontrivial limiting factor. Well, I can not comment about solid fills. since my graphs generally do not use many of those beasts. His reservation probably is well founded. However, when using a HPLJ as an output device for SAS/GRAPH, you have to remember that there are three parts to generating the graph: (1) have SAS/GRAPH build the graph, (2) transmit the graph to the HPLJ, and (3) have the HPLJ produce the hardcopy. Using tools such as PrintAPlot and PlotterInACartridge attack the first two parts. There is no doubt that SAS/GRAPH can generate a vectorized graph (PGL) graph much faster than a rasterized graph (PCL - the native of the HPLJ). Second, vectorized images tend to be (much) smaller than rasterized images, so it follows that the transmittal time will be a lot less. Even including the time needed for HPLJ (part 3) to make the hardcopy, some very significant speed increases can be seen. Joe Svec also sent in an additional query asking if PlotterInACartridge may not be better than PrintAPlot since it accepts the bed plotter commands directly and does not have to "translate" the graphics data into a form useable by the HPLJ. Well, both products translate - you are converting PGL into PCL. The benchmarks I have run show that time differences between the two products to produce hardcopy is insignificant. Is PlotterInACartridge worth the extra money? Perhaps. PlotterInACartridge is fairly transparent to the user. Merely insert the cartridge, tell SAS/GRAPH that the output device is a bed plotter (e.g., DEVICE = HP7475A), and away you go. With PrintAPlot, you still tell SAS/GRAPH that you are using a bed plotter but you must spool your output to disk. After the graph is generated, you leave (temporarily or not) SAS and run PrintAPlot - thank God the program does not need much RAM so that you merely have to shell out of SAS. After the hardcopy is produced, you can reenter SAS. My general experience with the aforementioned tools is that as the plot gets more complex, the time saved producing the hardcopy graph is even more significant. I have seen improvements on the order of 6000% (yes, 60 times faster).