
GPLOT recipes: Graph markers
A Graph Marker is a symbol, such as a cross, dot, or circle,
drawn on a graph to mark a specific point. Usually the symbol
used will be chosen to be symmetrical with a well-defined
center.
A marker is identified by a number given with symbol.
The symbol number can be: -1, to draw a dot of the
smallest possible size (one pixel); 0--31, to draw any one
of the symbols from the graph marker table
or 33--127, to draw the corresponding ASCII character
(the character is taken from the currently selected text
font); or >127, for any of the symbols from the Hershey symbol table,
see: Hershey symbols.
All GIPSY applications which accept text in a plot use the same syntax
\(nnnn)
for a Hershey symbol number. You can also use the Hershey symbols as graph
markers, but then you cannot use the Hershey symbols with numbers < 128
(because these numbers are reserved for ASCII characters).
GPLOT Example 1: Plot a '+' marker at position 0,0.
move 0 0
symbol 2
marker
GPLOT Example 2: Plot a copyright symbol (Hershey symbol) at position 0,0.
move 0 0
symbol 274
marker
GPLOT Example 3: Include a copyright character in a text
move 0 0
text Gipsy, \(0274) 1995
SYMBOL TABLES: