Plotter Part 2

24 EE June 1988 •..t..,•;),A .• • .•••*.k...•::::$•*."..k.:","*:•ttV•••*11" • No hardware without software, and vice versa. In this month"s final instalment we lend a hand to all constructors of the plotter who are eager to write control software, but need general algorithms, flow diagrams and elementary programming procedures as guidance for tailoring the communication patch between their computer, available graphics programs, and the plotter. Before attempting to write a plotter in- terface program, it is necessary to ac- quire a basic understanding of computer control (software/hardware) in combi- nation with graphics (or, more specifically, drawing). An algorithm needs to be devised for translating graphics information (on screen or in any form of memory) to actual pen posi- tioning commands. The low-cost plotter described last month has no "on-board" intelligence, and must, therefore, be con- trolled at the bit level by the computer. In order to ob...