目前，我使用 TikZ 阴影在我的文档中显示纵波，如下所示：
正弦值为 -1 时阴影为白色，正弦值为 1 时阴影为蓝色。这看起来还不错，但不幸的是它是 RGB 格式的，我需要一个干净的CMYK文档。上述问题让我使用来pgfplots制作阴影，但实际上我不知道如何……
这是我的 MWE
\documentclass{article}
\usepackage[cmyk]{xcolor}
\definecolor{wave}{cmyk}{1,0.35,0,0}
\usepackage{tikz}
\usetikzlibrary{calc}
\tikzset{
samples=100,
}
\usepackage{pgfplots}
\pgfplotsset{compat=1.11}
% Variables
\pgfmathsetmacro\T{1}
\pgfmathsetmacro\A{0.2}
\pgfmathsetmacro\N{5}
\pgfmathsetmacro\D{\N*\T}
\begin{document}
\section{With TikZ}
\begin{tikzpicture}
% Shading
\coordinate (C) at (0.25pt,0);% small overlapping
\foreach \x in {1,...,\N} {
\shade [shading=axis, right color=white, left color=wave, shading angle=90]
($(\x*\T-\T,-\A)-(C)$) rectangle ++($(\T/2,2*\A)+(C)$);
\shade [shading=axis, left color=white, right color=wave, shading angle=90]
($(\x*\T-\T/2,-\A)-(C)$) rectangle ++($(\T/2,2*\A)+(C)$);
}
% Cosine Wave
\draw [black] plot [id=sine, domain=0:\D]
function {\A*cos(2*pi/\T*x)};
\end{tikzpicture}
\section{With PGFplots}
\begin{tikzpicture}
\begin{axis}
\addplot [domain=0:\D] {\A*cos(2*pi/\T*x)};
\end{axis}
\end{tikzpicture}
\end{document}
如果我只能指定函数（例如，\A*cos(2*pi/\T*x)一个矩形来裁剪阴影），其余工作由 TeX 完成，那就太好了……
附加问题：我怎样才能模仿这样的径向阴影
完成
\pgfdeclareradialshading{wave}{\pgfpoint{0cm}{0cm}}%
{%
color(0.0cm)=(white);
color(0.01cm)=(white);
color(0.1cm)=(wave);
color(0.2cm)=(white);
color(0.3cm)=(wave);
color(0.4cm)=(white);
color(0.5cm)=(wave);
color(0.6cm)=(white);
color(0.7cm)=(wave);
color(0.8cm)=(white);
color(0.9cm)=(wave)
}
\begin{tikzpicture}
\shade [shading=wave] circle [radius=5] ;
\end{tikzpicture}
答案1
以下是尝试复制相同尺寸的尝试pgfplots：
\documentclass{standalone}
\usepackage[cmyk]{xcolor}
\definecolor{wave}{cmyk}{1,0.35,0,0}
\usepackage{tikz}
\usetikzlibrary{calc}
\tikzset{
samples=100,
}
\usepackage{pgfplots}
\pgfplotsset{compat=1.11}
% Variables
\pgfmathsetmacro\T{1}
\pgfmathsetmacro\A{0.2}
\pgfmathsetmacro\N{5}
\pgfmathsetmacro\D{\N*\T}
\begin{document}
\begin{tikzpicture}
% Shading
\coordinate (C) at (0.25pt,0);% small overlapping
\foreach \x in {1,...,\N} {
\shade [shading=axis, right color=white, left color=wave, shading angle=90]
($(\x*\T-\T,-\A)-(C)$) rectangle ++($(\T/2,2*\A)+(C)$);
\shade [shading=axis, left color=white, right color=wave, shading angle=90]
($(\x*\T-\T/2,-\A)-(C)$) rectangle ++($(\T/2,2*\A)+(C)$);
}
% Cosine Wave
\draw [black] plot [id=sine, domain=0:\D]
function {\A*cos(2*pi/\T*x)};
\end{tikzpicture}
\begin{tikzpicture}
\begin{axis}[
view={0}{90},
hide axis,
colormap={custom}{color=(white) color=(wave)},
trig format plots=rad,
x=1cm,
y=1cm,
z=0cm,
]
\addplot3[
domain=0:\D,samples=100,
domain y=-\A:\A,samples y=2,
surf,shader=interp,
] {\A*cos(2*pi/\T * x)};
\addplot [domain=0:\D,samples=100] {\A*cos(2*pi/\T*x)};
\end{axis}
\end{tikzpicture}
\end{document}
这个想法是使用surf从顶部查看的图。颜色数据是 的值f(x,y)，即 cos 值，线性映射到颜色图中。最小的颜色是“白色”，最大的是“波浪”。阴影在 CMYK 中生成，颜色插值也是如此。
可以使用以下方法进行径向阴影data cs=polar（即 x = 角度，y = 半径）：
\documentclass{standalone}
\usepackage[cmyk]{xcolor}
\definecolor{wave}{cmyk}{1,0.35,0,0}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=1.11}
% Variables
\pgfmathsetmacro\T{1}
\pgfmathsetmacro\A{0.2}
\pgfmathsetmacro\N{5}
\pgfmathsetmacro\D{\N*\T}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
view={0}{90},
hide axis,
colormap={custom}{color=(white) color=(wave)},
trig format plots=rad,
x=1cm,
y=1cm,
z=0cm,
]
\clip (-\D/2,-\D/2) rectangle (\D/2, \D/2);
\addplot3[
data cs=polar,
domain=0:2*pi,
domain y=0:\D,samples y=25,
surf,shader=interp,
] {\A*sin(2*pi/\T * y)};
\end{axis}
\end{tikzpicture}
\end{document}
答案2
如果您希望它更加灵活，您还可以使用 pgfplots 的 gnuplot 版本。
这里是 7 个点源的干涉图案的例子，具有下列参数 * \Lambda 是波长 * \DistanceSources 是源之间的恒定距离 * 振幅可以用函数“amorti”选择，但在距源 \Cutoff 的半径内保持恒定 * \RetardIIvsI 是两个相邻源之间的恒定相移 * \Date 是添加到所有源的恒定相位。
\documentclass{standalone}
\usepackage{tikz,pgfplots}
\begin{document}
\begin{tikzpicture}[]
\pgfmathsetmacro{\xmin}{-6}
\pgfmathsetmacro{\ymin}{-6}
\pgfmathsetmacro{\xmax}{6}
\pgfmathsetmacro{\ymax}{6}
\pgfmathsetmacro{\Lambda}{.5}
\pgfmathsetmacro{\DistanceSources}{\Lambda/2}
\pgfmathsetmacro{\CentreI}{-4*\DistanceSources}
\pgfmathsetmacro{\CentreII}{\CentreI+\DistanceSources}
\pgfmathsetmacro{\CentreIII}{\CentreII+\DistanceSources}
\pgfmathsetmacro{\CentreIV}{\CentreIII+\DistanceSources}
\pgfmathsetmacro{\CentreV}{\CentreIV+\DistanceSources}
\pgfmathsetmacro{\CentreVI}{\CentreV+\DistanceSources}
\pgfmathsetmacro{\CentreVII}{\CentreVI+\DistanceSources}
\pgfmathsetmacro{\Cutoff}{\Lambda/10}
\pgfmathsetmacro{\RetardIIvsI}{pi/2}
\pgfmathsetmacro{\Date}{0}
\begin{axis}[colormap/blackwhite,
view ={0}{90},
xlabel = $x$,
ylabel = $y$,
extra x ticks = ,
extra x tick labels = ,
extra y ticks = ,
extra y tick labels = ,
xmin = \xmin,
ymin = \ymin,
xmax = \xmax,
ymax = \ymax,
domain = \xmin:\xmax,
samples = 50
]
\addplot3[surf,shader=interp,raw gnuplot] gnuplot {
set isosamples 50,50;
amorti (centre,xy,y,cutoff)= 1;
interf(centre,date,x,y,cutoff,lambda,retard) =%
amorti(centre,x,y,cutoff)%
* cos(date-2*pi*sqrt((x-centre)**2 + y**2)/lambda-retard);
splot [x=\xmin:\xmax] [y=\ymin:\ymax] 1./7.*(%
interf(\CentreI,\Date,x,y,\Cutoff,\Lambda,0)%
+ interf(\CentreII,\Date,x,y,\Cutoff,\Lambda,\RetardIIvsI)%
+ interf(\CentreIII,\Date,x,y,\Cutoff,\Lambda,2*\RetardIIvsI)%
+ interf(\CentreIV,\Date,x,y,\Cutoff,\Lambda,3*\RetardIIvsI)%
+ interf(\CentreV,\Date,x,y,\Cutoff,\Lambda,4*\RetardIIvsI)%
+ interf(\CentreVI,\Date,x,y,\Cutoff,\Lambda,5*\RetardIIvsI)%
+ interf(\CentreVII,\Date,x,y,\Cutoff,\Lambda,6*\RetardIIvsI)%
)
};
\end{axis}
\end{tikzpicture}
\end{document}
