Method used to denote a single point in the graph

[Derek-Jones]

The method used by particular a pdf generation tool to denote a single point (e.g., circle or cross) needs to be identified. Tools often embed an identifying string in the pdf they generate.

Some tools create their own 'point' character by, for instance, drawing vertical/horizontal lines. Things get complicated when the tool generates pdf operations that draws all the horizontal lines first, followed by all the vertical lines (or vice versa).

The following draws a circle on the page:
/F1 1 Tf 1 Tr 6.21 0 0 6.21 135.35 423.79 Tm (l) Tj 0 Tr