HP 1200 HP PCL/PJL reference - PCL 5 Comparison Guide - Page 74

Note Placement Variations PCL and HP-GL/2 (see following pages for HP-GL/2 pixel placement command description) provide two pixel placement modes: grid intersection (the default) and grid centered. Grid intersection places pixels on the intersections of the grid (see Figure 2-2). Grid centered places pixels in the center of the grid. In Figure 2-2, a rectangle extends from position (1,1) to (3,4). The grid centered model produces a rectangle one dot thinner and one dot shorter then the grid intersection model. When rectangular area fills are used and grid intersection is used, an overlapping of pixels can occur if rectangular area fills are placed adjacent to one another (as shown below). Depending on the raster operation presently in effect, this overlap can produce undesirable results in the final printed image. To avoid this problem, use the grid centered method. Since PCL printers print only at intersections, grid centered is implemented as shown on the right. Figure 2-2 Pixel Placement Variations 2-26 Printer-Specific Differences ENWW