Re: [Octave-bug-tracker] [bug #64956] 'color' isn't a supported property of a contour group but... it should. Or doc should be more explicit

[Alain . Cochard]

Pantxo Diribarne writes on Fri  1 Dec 2023 15:02:
 > Follow-up Comment #1, bug #64956 (project octave):
 > 
 > According to ML doc, "linecolor", which Octave uses, is now
 > discouraged in favor of "edgecolor". So, rather than adding the
 > undocumented property "color" (probably a relic of old ML syntax
 > that they well could forbid without warning in a future version),
 > Octave should introduce the official "edgecolor" property in order
 > to make ML code, written against documented properties, run fine in
 > Octave as well.
 > 
 > As for the difference between `plot` and `contour`: The `plot`
 > function produces line objects, and the "color" property makes
 > sense because it directly refers to the color of the main object,
 > the line. On the other hand, the `contour(f)` functions essentially
 > produce groups of patch objects, which have both edge and face
 > colors, hence the distinction.

Thanks a lot for the detailed answer and the clarification about edge
and face colors -- I had not thought about that.

I still think that 'color' is the most natural property to think about
(at least considering the current documentation of contour, both
Octave & ML) , since (1) it is what 'plot' --the main plotting
function-- uses, (2) only the lines are important when 'contour' is
used (by default at least), (3) when 'contourf' is used, the lines are
not so important, plus they are _several_ face colors anyway.

So maybe this is the reason why ML still supports 'color'?

What would be the big deal of Octave supporting it as well, at least
until ML suppresses it?  There could be a warning message like
"'color' might be suppressed in the future, use 'edgecolor' instead".

At least it might be nice to also point to 'edgecolor' instead of just
the message "error: set: unknown hggroup property Color".

Best wishes.

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