color
Can anyone write a macro that will modify the xcolor package so that using !x will darken colors when x < 100 and lighten colors when x is between 100 and 200?
e.g., I would like to be able to do
red!50 and red!150 to get a dark and light red color respectively instead of having to do red!50!black.
(I'm guessing a lot here.) I think that it is down to the way in which PGF inserts colours in to the output file. To see this, it's worth reviewing the levels in the TikZ/PGF system.
So the thing to remember in this is that when you say \fill[color=RedSpot] then that is a TikZ command to set the colour to RedSpot which then gets further interpreted by PGF and then the driver. Chasing definitions through, we find that color=RedSpot calls \pgfsetcolor which calls \pgf@setcolor which calls \pgfsys@color@<model>. This is now a driver level command. Its definition, say for CMYK, is
\def\pgfsys@color@cmyk@stroke#1#2#3#4{\pgfsysprotocol@literal{#1 #2 #3 #4 K}}
from which we can see (and tracing back through the definitions, this gets clearer) that even if we've defined a colour name, it is the CMYK values that get put in the file.
The point is that PGF cannot know that it is possible in PDF to alias colours, because it doesn't know that the final output will be PDF. So it translates the colours to their raw values. And 0 1 1 0 setcmykcolor isn't the spot colour.
A lot of the above is speculation, I'll admit. Here's my evidence for this being the case. If you compile the PSTricks file above and look at the PS, you'll find that the drawing code is:
tx@Dict begin STP newpath /ArrowA { moveto } def /ArrowB { } def
0.8 SLW TeXDict begin XC@black end 142.26378 142.26378 113.81102
.5 CLW mul sub 0 360 arc closepath gsave TeXDict begin XC@RedSpot
end 1. .setopacityalpha fill grestore end
But if you compile the TikZ version and look at the PS, you'll find:
0 1 1 0 setcmykcolor
141.73404 141.73404 moveto
255.12128 141.73404 moveto
255.12128 204.35689 204.35689 255.12128 141.73404 255.12128 curveto
79.11119 255.12128 28.3468 204.35689 28.3468 141.73404 curveto
28.3468 79.11119 79.11119 28.3468 141.73404 28.3468 curveto
204.35689 28.3468 255.12128 79.11119 255.12128 141.73404 curveto
closepath
So the RedSpot gets put literally in to the PS from PSTricks but is translated back to 0 1 1 0 internally by PGF first.
The clincher is to do the following. Edit the PS file and replace the 0 1 1 0 setcmykcolor by XC@RedSpot. Then do the gs and montage stuff, and you get:
which is what you wanted.
However, editing the postscript isn't a great way to do this! Here's what I think you'd have to do to use spot colours in TikZ. I think you'd have to define a new colour model, say spot. You'd then tell PGF that the spot colour model is to be treated specially in that the name of the colour is to be used (or at least XC@<name>). To define a spot colour, you could (I think) use xcolor to define it using one model and then convert it to another. That would ensure that the definition got in to the PS file (which it does already). I don't know how to do all those steps, because it relies on knowing how xcolor works and I don't know much about that. But that's what I would do.
This is an edit of Stefan Pinnow:
Jake is referring to a non-PGFPlots/external colorbrewer library of (I guess LoopSpace). For the PGFPlots/internal colorbrewer library please have a look at my answer.
There is now a PGFPlots library colorbrewer that creates cycle lists using the colorbrewer color schemes. The color values are taken from the ColorBrewer Excel file.
To set a colorbrewer cycle list, you call colorbrewer cycle list=<scheme>, which will define the necessary colors (colorbrewer1 to colorbrewer8) and create a cycle list called colorbrewer.
The number of colors and plot styles that are defined can be set using the key colorbrewer values=<number>.
\documentclass{article}
\usepackage{pgfplots}
\usepgfplotslibrary{colorbrewer}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
colorbrewer cycle list=Dark2
]
\addplot {rnd};
\addplot {rnd-1};
\addplot {rnd-2};
\addplot {rnd-3};
\addplot {rnd-4};
\addplot {rnd-5};
\addplot {rnd-6};
\addplot {rnd-7};
\end{axis}
\end{tikzpicture}
\end{document}
Here's an overview of the color schemes:
Best Answer
Here a suggestion. I defined a command
\mycolorcmdwhich behaves like\colorbut with the test if the number is greater than 100. The following output is created by: