Re: what should monochrome option do exactly?

[sfeam (E. Merritt) <eam...@gm...>]

On Tuesday, 13 December 2011, Mojca Miklavec wrote:
> On Tue, Dec 13, 2011 at 23:32, Ethan A Merritt wrote:
> > On Tuesday, December 13, 2011 02:19:58 pm Mojca Miklavec wrote:
> >> Hello,
> >>
> >> I just remembered that implementation of monochrome option in context
> >> terminal is slightly suboptimal (in standalone mode it lets TeX do
> >> color conversion into gray scale as "rgb2gray").
> >>
> >> I should probably fix that, but I'm not sure what exactly to do:
> >> should I simply make all the colors black or should I use different
> >> shades of gray, and in the second case - which colors exactly?
> >
> > In my opinion, which may not be universally shared,
> > 'set term foo monochrome' should cause it to choose a default palette
> > in shades of grey, and a default set of lines that are not colored.
> 
> On the other hand, mochrome means "mono" (= single color).

Like black and white photography?  Black and white movies?

> I understand the second. The colors lc 1, lc 2, ... should be gray,
> except that I would be grateful for some proposal of which shades of
> gray exactly.

Do you really mean "lc"?  Why would you use that if not to set colors?

The default sequence of line _types_ should IMHO all be black, for better
reproduction in print.  Use  "set term post mono dashed" as a model.
Something like  solid / dot / thick / dash / dot-dot-dash

But really in version 4.5 you don't need a special terminal option for
this.  You would just need to load a "mono" set of linetypes.

> But what exactly is meant with default palette? PM3D? But how can a
> terminal influence the choice of palette formulas?

Again look at the postscript terminal.  A greyscale palette is really
easy. It doesn't need any formulae unless you want to get fancy and
handle gamma correction.

	Ethan

> > But it should not prevent the user from drawing explicitly in whatever
> > color they like, and it should not prevent the user from selecting a
> > color palette later.
> 
> What exactly do you mean with selecting a color palette? (Probably the
> same question as earlier.)
> 
> > I see it as exactly analagous to "set term foo dashed", which
> > defaults to dashed lines but does not stop you from explictly
> > drawing with solid lines instead
> 
> Yes, but solid line is one particular type of dashed line (one can
> always draw with "lt 0 lc 3"), while the opposite is not true. If one
> selects "solid", it is impossible to draw dashed lines later.
> 
> In the same way, if one chooses "color", one can always plot with "lc
> 0" (black) or with proper black since black is just one type of color.
> (If analogy with dashes was true, one would not be able to draw in
> color once monochrome is selected. On the other hand there exists a
> mechanism to set colors explicitly as rgb values, but no mechanism to
> set an explicit dash type [unless I'm mistaken].)
> 
> Mojca
>