Re: what should monochrome option do exactly?

[Daniel J S. <dan...@ie...>]

On 12/13/2011 06:37 PM, 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).
> 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.

What object is it exactly that the monochrome qualifier refers to? 
Lines, images, symbols?  All of the above?

Monochrome means as you say, a single color or point on the chromatic 
scale.  However, I'd say that greyscale is a special type of monochrome. 
  The thing that varies in monochrome is the intensity of the light 
source (i.e., pixel) while the color components remain fixed, relatively 
speaking.  Greyscale is a monochrome in which all primary components are 
weighted equally.  However, one could create a monochrome image where 
the color components (RGB) are not weighted equally.  Examples of this 
would be well known historic photographic prints that, for example, have 
a sepia tone.

So with the "monochrome" option, I'd suggest a second qualifier option 
which is the RGB components.  (We must have a standard way of expressing 
RGB by now.  Names might work too.)  For example,

set term foo monochrome (1,0.8,0.5)
set term foo monochrome red
   [above is equivalent to "set term foo monochrome (1,0,0)"]
set term foo monochrome sepia

Thoughts?


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

Color palette is different from monochrome and different from RGB. 
Palette is a series of colors acting as a look-up-table for various 
values.  Give the LUT a value of 3 and it returns a triple representing 
the RGB values.  The palette can be asigned vary strange color 
combinations to create various effects, e.g., weather map, cartography, 
so on.

Dan