★ APPLICATIONS ★ PAO/PRESSE ★ Quick on the draw|Computing with the Amstrad) ★ |
| Stop Press Page Printer (Computing with the Amstrad) | Applications Pao/presse |
JOHN BLESSING puts Stop Press printing into top gear THE arrival of Advanced Memory Systems' Stop Press (Pagemaker) for the CPC caused a surge of interest in desktop publishing among home users. Despite its many problems when first released, this program has been very successful. The quality of its output is superb, but the dot matrix printer needs to spend well over an hour producing a high-quality page. Even in draft mode this can take at least half an hour. Until now if you wanted to reduce this time there was only one option - buy a laser printer. However, it is now possible to speed up page printing with the programs presented here. It is interesting to consider why the print routine in Stop Press is so slow, and to do this we need to understand the layout of a page. Stop Press constructs it out of 568 rows, each of which is 114 bytes wide. When saved to disc the page is cut horizontally into four strips and put into separate files. The problem is that a single row using one pin of the print head is 3/216in deep, and some simple arithmetic shows that 568 rows would only be three quarters of the correct length for A4 paper. It seems that Stop Press prints every row twice with a 1/216in line feed in between. This makes every row about one third deeper, so the page is stretched to fit A4 format. It also makes it so slow that a second hobby is needed to pass the time while waiting for it to finish printing. The obvious solution is to have more rows, but that would mean using more memory which is in short supply in Stop Press. Program II works by printing seven rows at once which considerably reduces the time taken. There are still only 568 rows to a page and the bottom row of each set of seven has to be repeated to get the correct page length. The time taken to print a page is now approximately 15 minutes, with only a small reduction in quality -certainly good enough in most cases. Choose draft mode if you really want to speed things up. Here none of the rows are repeated, so a gap is left between each block of seven. It might not look too great, but it takes even less time and is useful for checking page layout. Program I must be typed in and saved before running. It generates the machine code which is then saved as PMEPSON.BIN. Program II loads this code and then asks for the required print mode, and will then prompt you to insert your page disc and let you select the page you wish to print. Each of the four files which make up a page are loaded in turn and control passes to the machine code. The Escape key is not tested during printing, so if you want to stop you will have to remove the disc before the next quarter page is loaded. Stop Press is fussy about the type of printer it will drive. Generally speaking it will work with Epsons and others which expect 960 bits in graphics mode. Many printers use 1280, so the page tends to be squashed in the left two thirds of the paper. If you have this problem do not despair. If there is sufficient interest, a later article will describe how a full-width page can be produced even on these printers.
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