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tikz 中的渐变着色

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tikz 中的渐变着色

我有一张图，其中颜色应沿导线渐变。确切地说，颜色应像正弦函数。

\documentclass[border=2mm]{standalone}

\usepackage{tikz}
\usetikzlibrary{calc}

\newcommand\wireheight{2} % height of one segment
\newcommand\wirewidth{1}  % width of a segment
\newcommand\wiredist{0.5} % distance between wires
\pgfmathsetmacro\pairdist{2*(\wirewidth+\wiredist)} % distance between pairs of wires

% \wire[options]{name}{start}{height}{width}
\newcommand\wire[5][]%
{\draw[#1]
    (#3)            coordinate (#2-0)
    -- ++(0,#4)     coordinate (#2-1)
    -- ++(#5,0)     coordinate (#2-2)
    -- ++(0,#4)     coordinate (#2-3)
    -- ++(-#5,0)    coordinate (#2-4)
    -- ++(0,#4)     coordinate (#2-5)
    -- ++(#5,0)     coordinate (#2-6)
    -- ++(0,0.5*#4) coordinate (#2-7);
}

\begin{document}
    \begin{tikzpicture}[rounded corners,>=stealth, shorten >=1pt, shorten <=1pt]
    \foreach \i in {0,...,2}
    {
        \wire[thick,red]{G-\i}{{(\i)*\pairdist-\wiredist},0}{\wireheight}{-\wirewidth}
        \wire[thick,blue]{B-\i}{\i*\pairdist,0}{\wireheight}{\wirewidth}
    }
    \draw[<->] ($(G-1-2)!0.5!(G-1-3)$) -- +(-0.5,0) node[midway,above]{$\kappa_{2}$};
    \draw[<->] ($(G-1-2)!-0.5!(G-2-3)$) -- +(-0.5,0) node[midway, above]{$\kappa_{1}$};
    \end{tikzpicture}
\end{document}

我想要蓝色和红色的渐变色。比如底部为零，然后沿着电线增加，经过一个周期后达到初始值，以此类推。只是为了说明我的意思。这是一个周期。 在此处输入图片描述 我只是试图从电线的粗细来显示颜色的强度（没有其他东西可以显示）

答案1

我尝试使用Alain Matthes 的绝招针对您的 MWE，但由于错误而无法正常工作dimension too large。更准确地说，我尝试使用着色部分。事实上，他提到他从 Mark Wilbrow 那里学到了着色部分，但我无法找到相应的帖子。如果阅读本文的人知道这一点，那么如果您能让我知道以便我可以给予适当的赞扬，那就太好了。

无论如何，我们可以通过放弃rounded corners并用弧线手工绘制它们来使其工作。然后，我们可以采用稍微修改过的 Mark-Wibrow-Alain-Matthes 装饰版本，并使用正弦函数（而不是线性函数）来确定颜色的组成。

\documentclass[border=2mm,tikz]{standalone}
\usetikzlibrary{calc}

\newcommand\wireheight{2} % height of one segment
\newcommand\wirewidth{1}  % width of a segment
\newcommand\wiredist{0.5} % distance between wires
\pgfmathsetmacro\pairdist{2*(\wirewidth+\wiredist)} % distance between pairs of wires

% \wire[options]{name}{start}{height}{width}
\newcommand\wire[5][]%
{\draw[#1]
    (#3)            coordinate (#2-0)
    -- ++(0,#4-#5)     coordinate (#2-1)
    arc(00:90:#5/2) arc(-90:-180:#5/2)    coordinate (#2-2)
    -- ++(0,#4-#5)     coordinate (#2-3)
    arc(180:90:#5/2) arc(-90:00:#5/2)    coordinate (#2-4)
    -- ++(0,#4-#5)     coordinate (#2-5)
    arc(00:90:#5/2) arc(-90:-180:#5/2)    coordinate (#2-6)
    -- ++(0,0.5*#4) coordinate (#2-7);
}

\usetikzlibrary{decorations}
\begin{document}

\makeatletter % starting point: from https://tex.stackexchange.com/a/14295/121799

\pgfkeys{/pgf/decoration/.cd,
         start color/.store in =\startcolor,
         end color/.store in   =\endcolor
}
\newcounter{alongline}

\pgfdeclaredecoration{sinoidal color change}{initial}{
 \state{initial}[width=0pt, next state=line]{\setcounter{alongline}{0}}
 \state{line}[width=0.5pt]{%
   %\pgfsetarrows{-}%
   \stepcounter{alongline}
   \pgfmathsetmacro{\x}{100*sin(1.8*\thealongline*(50pt/\pgfdecoratedpathlength))}
   % \typeout{\thealongline:\x,\pgfdecoratedpathlength}
   \pgfpathmoveto{\pgfpointorigin}%
   \pgfpathlineto{\pgfqpoint{.75pt}{0pt}}%
   \pgfsetstrokecolor{\endcolor!\x!\startcolor}%
   \pgfusepath{stroke}%
 }
 \state{final}{%
   %\pgfsetlinewidth{\pgflinewidth}%
   \pgfpathmoveto{\pgfpointorigin}%
   %\color{\endcolor!\x!\startcolor}%
   \pgfusepath{stroke}% 
 }
}

\makeatother
    \begin{tikzpicture}[>=stealth, shorten >=1pt, shorten <=1pt]
    \foreach \i in {0,...,2}
    {
       \begin{scope}[xscale=-1]
        \wire[thick,decoration={sinoidal color change,   
start color=red, end color=blue},decorate]{G-\i}{{-(\i)*\pairdist-\wiredist},0}{\wireheight}{\wirewidth}
       \end{scope}
        \wire[thick,decoration={sinoidal color change,   
start color=yellow, end color=red},decorate]{B-\i}{\i*\pairdist,0}{\wireheight}{\wirewidth}
    }
    \draw[black,<->] ($(G-1-2)!0.5!(G-1-3)$) -- ($(G-2-2)!0.5!(G-2-3)$) node[midway,above]{$\kappa_{2}$};
    %\draw[<->] ($(G-1-2)!-0.5!(G-2-3)$) -- +(-0.5,0) node[midway, above]{$\kappa_{1}$};
    \end{tikzpicture}

\end{document}

在此处输入图片描述

我尝试过模仿你的电线。如果这是你想要的方式，我很乐意改进装饰。

编辑：这是颜色在两种“边界颜色”之间振荡的版本。振荡次数由数字给出\NumMax。

\documentclass[border=2mm,tikz]{standalone}
\usetikzlibrary{calc}

\newcommand\wireheight{2} % height of one segment
\newcommand\wirewidth{1}  % width of a segment
\newcommand\wiredist{0.5} % distance between wires
\pgfmathsetmacro\pairdist{2*(\wirewidth+\wiredist)} % distance between pairs of wires

% \wire[options]{name}{start}{height}{width}
\newcommand\wire[5][]%
{\draw[#1]
    (#3)            coordinate (#2-0)
    -- ++(0,#4-#5)     coordinate (#2-1)
    arc(00:90:#5/2) arc(-90:-180:#5/2)    coordinate (#2-2)
    -- ++(0,#4-#5)     coordinate (#2-3)
    arc(180:90:#5/2) arc(-90:00:#5/2)    coordinate (#2-4)
    -- ++(0,#4-#5)     coordinate (#2-5)
    arc(00:90:#5/2) arc(-90:-180:#5/2)    coordinate (#2-6)
    -- ++(0,0.5*#4) coordinate (#2-7);
}

\usetikzlibrary{decorations}
\begin{document}

\makeatletter % starting point: from https://tex.stackexchange.com/a/14295/121799

\pgfkeys{/pgf/decoration/.cd,
         start color/.store in =\startcolor,
         end color/.store in   =\endcolor
}
\newcounter{alongline}

\pgfmathsetmacro{\NumMax}{3}
\pgfdeclaredecoration{sinoidal color change}{initial}{
 \state{initial}[width=0pt, next state=line]{\setcounter{alongline}{0}}
 \state{line}[width=0.5pt]{%
   %\pgfsetarrows{-}%
   \stepcounter{alongline}
   \pgfmathsetmacro{\x}{50*(1+cos(\NumMax*1.8*\thealongline*(50pt/\pgfdecoratedpathlength)))}
   % \typeout{\thealongline:\x,\pgfdecoratedpathlength}
   \pgfpathmoveto{\pgfpointorigin}%
   \pgfpathlineto{\pgfqpoint{.75pt}{0pt}}%
   \pgfsetstrokecolor{\endcolor!\x!\startcolor}%
   \pgfusepath{stroke}%
 }
 \state{final}{%
   %\pgfsetlinewidth{\pgflinewidth}%
   \pgfpathmoveto{\pgfpointorigin}%
   %\color{\endcolor!\x!\startcolor}%
   \pgfusepath{stroke}% 
 }
}

\makeatother
    \begin{tikzpicture}[>=stealth, shorten >=1pt, shorten <=1pt]
    \foreach \i in {0,...,2}
    {
       \begin{scope}[xscale=-1]
        \wire[thick,decoration={sinoidal color change,   
start color=red, end color=blue},decorate]{G-\i}{{-(\i)*\pairdist-\wiredist},0}{\wireheight}{\wirewidth}
       \end{scope}
        \wire[thick,decoration={sinoidal color change,   
start color=yellow, end color=red},decorate]{B-\i}{\i*\pairdist,0}{\wireheight}{\wirewidth}
    }
    \draw[black,<->] ($(G-1-2)!0.5!(G-1-3)$) -- ($(G-2-2)!0.5!(G-2-3)$) node[midway,above]{$\kappa_{2}$};
    %\draw[<->] ($(G-1-2)!-0.5!(G-2-3)$) -- +(-0.5,0) node[midway, above]{$\kappa_{1}$};
    \end{tikzpicture}

\end{document}

在此处输入图片描述

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