Re: [transferred from Email] Providing/exporting a table of plot style properties

[Ralf J. <jue...@cs...>]

On Sat, 3 Jan 2009, Ethan A Merritt wrote:

> [from a conversation started off list]
> [summary] The question is whether the code in get_data()
> plot2d.c lines 327ff   can be replaced by a table-lookup,
> or deleted altogether.   This code sets limits min_cols and max_cols
> for the number of columns specified in the "using" part of a plot
> command.  Ralf's proposed table would also hold properties like
> PLOT_STYLE_HAS_FILL that are currently single bits set in the
> line style definitions in gp_types.h

The number of data columns all the plotting style accepts and
what optional columns they may take (for variable line color
or variable point size) is scattered across the documentation.
There currently does not seem to be a place in the code that
makes this information explicit. I think it would be useful to
have this, however, for the reasons stated below.

>> While my main motivation for this patch his making plot style
>> properties explicit to applications that generate gnuplot
>> scripts, it certainly is useful in that it improves clarity
>> of the code. And I would not be surprised if having such a
>> descriptor table would enable simplifications at other places
>> as well. The reason I would rather see it builtin and used
>> than external is that this guarantees the table is current.


While working on this patch I noticed that xyerrorlines takes
up to six data columns plus optionally two more (ps variable, lc
variable), which exceeds MAXDATACOLS in datafile.h. Is this a
known problem?

Ralf