Pen Colors

PEN pen-num selects a color from the table below (or an actual pen from a plotter). The colors or gray scales produced by each pen depend on the states of the COLOR and INVERT options used in loading the driver, as well as the state of the COLOR MAP option of the HTBasic CRT driver. If the COLOR MAP option is off, the following gray levels or colors are used:

Pen	Gray	Color	Gray Invert	Color Invert
0	white	white	black	black
1	black	black	white	white
2	30% black	red	70% black	red
3	89% black	yellow	21% black	yellow
4	59% black	green	41% black	green
5	70% black	cyan	30% black	cyan
6	11% black	blue	89% black	blue
7	40% black	violet	60% black	violet
8	black	black	white	white
9	30% black	red	70% black	red
10	89% black	yellow	21% black	yellow
11	59% black	green	41% black	green
12	70% black	cyan	30% black	cyan
13	11% black	blue	89% black	blue
14	40% black	violet	60% black	violet
15	black	black	white	white

If the COLOR option is used and the COLOR MAP option of the CRT driver is on, the plot is made using the colors in the HTBasic color map

If the COLOR option is not used, the colors in the HTBasic color map are converted to shades of gray using the NTSC equation:

brightness = 11% blue + 59% green + 30% red

The sign of the pen is ignored with both pen plotters and printers,