我怎样才能定义和发展像这样的形状
在 Tikz 中？
如果可能的话，有一个在上三角形内书写的选项就太好了（这样形状就可以拉伸了）
答案1
快速解决方案（某些设置可能会进一步调整）：
\documentclass{article}
\usepackage{varwidth}
\usepackage{tikz}
\usetikzlibrary{calc}
\newlength\mylen
\newlength\maxwd
\newcommand\Text{}
\newcommand\Envelope[1]{%
\renewcommand\Text{#1}
\settowidth\maxwd{\Text}
\setlength\mylen{\maxwd}
\multiply\mylen by2
\ifdim\mylen>5cm
\setlength\mylen{4cm}
\fi
\begin{tikzpicture}[line width=4pt]
\coordinate (A) at (0,0);
\coordinate (B) at (1.41\mylen,-\mylen);
\clip
([xshift=-0.5\pgflinewidth,yshift=0.5\pgflinewidth]A) --
([xshift=0.5\pgflinewidth,yshift=0.5\pgflinewidth]A-|B) --
([xshift=0.5\pgflinewidth,yshift=-0.5\pgflinewidth]B) --
([xshift=-0.5\pgflinewidth,yshift=-0.5\pgflinewidth]B-|A) --
([xshift=-0.5\pgflinewidth,yshift=0.5\pgflinewidth]A);
\draw[fill=gray!20,line cap=rect]
(A) -- (A-|B) -- (B) -- (B-|A) -- (A);
\draw
(B-|A) -- (0.705\mylen,-.3\mylen) -- (B);
\draw[fill=gray!30,rounded corners=15pt]
(A) -- (0.705\mylen,-0.6\mylen) -- (A-|B);
\node[anchor=north]
at ($ (A)!0.5!(B|-A) $ ) {\parbox{\mylen}{\centering\Text}};
\draw (A) -- (B|-A);
\end{tikzpicture}
}
\begin{document}
\Envelope{Eyes only}
\Envelope{Some longer text for the example}
\end{document}
答案2
这是这种形状的定义的开始。
目前不考虑键/pgf/minimum width和的值/pgf/minimum height。代码的（注释掉的）部分有问题，我不知道如何解决。
代码
\documentclass[tikz,convert]{standalone}
\makeatletter
\pgfset{envelope radius/.initial=+10pt,
envelope angle/.initial=40}
\def\pgfmath@smuggleOne#1\endgroup{%
\expandafter\endgroup\expandafter#1\expandafter=\the#1\relax}
\pgfdeclareshape{envelope}{%
\savedanchor\northeast{%
\pgfmathsetcount\pgfutil@tempcnta{\pgfkeysvalueof{/pgf/envelope angle}}%
\pgfmathtan@{\the\pgfutil@tempcnta}%
\let\pgf@sh@envelope@tan\pgfmathresult
\pgfmathcot@{\the\pgfutil@tempcnta}%
\let\pgf@sh@envelope@cot\pgfmathresult
% \pgfmathsin@{\the\pgfutil@tempcnta}%
% \let\pgf@sh@envelope@cos\pgfmathresult
\pgfmathsetlength\pgf@xc{\pgfkeysvalueof{/pgf/inner xsep}}%
\pgfmathsetlength\pgf@yc{\pgfkeysvalueof{/pgf/inner ysep}}%
% \pgfmathsetlength\pgf@xb{\pgfkeysvalueof{/pgf/minimum width}}%
% \pgfmathsetlength\pgf@yb{\pgfkeysvalueof{/pgf/minimum height}}%
\pgfmathsetlength\pgf@xa{\pgfkeysvalueof{/pgf/outer xsep}}%
\pgfmathsetlength\pgf@ya{\pgfkeysvalueof{/pgf/outer ysep}}%
%
\pgf@x=.5\wd\pgfnodeparttextbox
\advance\pgf@x by \pgf@xc%
\pgfutil@tempdima=\pgf@x
\pgf@y=\ht\pgfnodeparttextbox
\advance\pgf@y by \dp\pgfnodeparttextbox
\advance\pgf@y by 2\pgf@yc
\pgfutil@tempdimb=\pgf@y
%
\advance\pgf@x by \pgf@sh@envelope@cot\pgf@y
\multiply\pgf@x by 2
%
% \ifdim\pgf@x<\pgf@xb%
% \pgf@x=\pgf@xb%
% \fi%
%
\pgf@x=.5\pgf@x%
% % Excursus: (Re-)Calculate minimum height
% \begingroup
% \pgfmathsetlengthmacro\pgf@temp{\pgf@sh@envelope@cos*(\pgfkeysvalueof{/pgf/envelope radius})}%
% \multiply\pgf@x by \pgf@sh@envelope@tan
% \advance\pgf@x by \pgf@temp
% \multiply\pgf@x by 2
% \ifdim\pgf@yb<\pgf@x
% \pgf@yb=\pgf@x
% \fi
% \pgfmath@smuggleOne\pgf@yb
% \endgroup
%
\advance\pgf@x by.5\wd\pgfnodeparttextbox%
\advance\pgf@x by\pgf@xa%
%
\multiply\pgfutil@tempdima by \pgf@sh@envelope@tan
\advance\pgf@y by .5\pgfutil@tempdima
\multiply\pgf@y by 2
%
% \ifdim\pgf@y<\pgf@yb%
% \pgf@y=\pgf@yb%
% \fi%
%
\pgf@y=.25\pgf@y%
\advance\pgf@y by-.5\dp\pgfnodeparttextbox%
\advance\pgf@y by.5\ht\pgfnodeparttextbox%
\advance\pgf@y by\pgf@ya%
}
\savedanchor\southwest{%
\pgfmathsetcount\pgfutil@tempcnta{\pgfkeysvalueof{/pgf/envelope angle}}%
\pgfmathtan@{\the\pgfutil@tempcnta}%
\let\pgf@sh@envelope@tan\pgfmathresult
\pgfmathcot@{\the\pgfutil@tempcnta}%
\let\pgf@sh@envelope@cot\pgfmathresult
% \pgfmathsin@{\the\pgfutil@tempcnta}%
% \let\pgf@sh@envelope@cos\pgfmathresult
\pgfmathsetlength\pgf@xc{\pgfkeysvalueof{/pgf/inner xsep}}%
\pgfmathsetlength\pgf@yc{\pgfkeysvalueof{/pgf/inner ysep}}%
% \pgfmathsetlength\pgf@xb{\pgfkeysvalueof{/pgf/minimum width}}%
% \pgfmathsetlength\pgf@yb{\pgfkeysvalueof{/pgf/minimum height}}%
\pgfmathsetlength\pgf@xa{\pgfkeysvalueof{/pgf/outer xsep}}%
\pgfmathsetlength\pgf@ya{\pgfkeysvalueof{/pgf/outer ysep}}%
%
\pgf@x=.5\wd\pgfnodeparttextbox
\advance\pgf@x by \pgf@xc%
\pgfutil@tempdima=\pgf@x
\pgf@y=\ht\pgfnodeparttextbox
\advance\pgf@y by \dp\pgfnodeparttextbox
\advance\pgf@y by 2\pgf@yc
\pgfutil@tempdimb=\pgf@y
%
\advance\pgf@x by \pgf@sh@envelope@cot\pgf@y
\multiply\pgf@x by 2
%
% \ifdim\pgf@x<\pgf@xb%
% \pgf@x=\pgf@xb%
% \fi%
%
\pgf@x=-.5\pgf@x%
% % Excursus: (Re-)Calculate minimum height
% \begingroup
% \pgfmathsetlengthmacro\pgf@temp{\pgf@sh@envelope@cos*(\pgfkeysvalueof{/pgf/envelope radius})}%
% \multiply\pgf@x by -\pgf@sh@envelope@tan
% \advance\pgf@x by \pgf@temp
% \multiply\pgf@x by 2
% \ifdim\pgf@yb<\pgf@x
% \pgf@yb=\pgf@x
% \fi
% \pgfmath@smuggleOne\pgf@yb
% \endgroup
%
\advance\pgf@x by.5\wd\pgfnodeparttextbox%
\advance\pgf@x by-\pgf@xa%
%
\multiply\pgfutil@tempdima by \pgf@sh@envelope@tan
\advance\pgf@y by .5\pgfutil@tempdima
\multiply\pgf@y by 2
%
% \ifdim\pgf@y<\pgf@yb%
% \pgf@y=\pgf@yb%
% \fi%
%
\pgfutil@tempdima=-.5\pgf@y
\pgf@y=-.25\pgf@y%
\advance\pgf@y by-.5\dp\pgfnodeparttextbox%
\advance\pgf@y by.5\ht\pgfnodeparttextbox%
\advance\pgf@y by-\pgf@ya%
\advance\pgf@y by \pgfutil@tempdima
}
\inheritanchorborder[from=rectangle]
\inheritanchor[from=rectangle]{center}
\inheritanchor[from=rectangle]{north}
\inheritanchor[from=rectangle]{south}
\inheritanchor[from=rectangle]{west}
\inheritanchor[from=rectangle]{east}
\inheritanchor[from=rectangle]{north west}
\inheritanchor[from=rectangle]{north east}
\inheritanchor[from=rectangle]{south west}
\inheritanchor[from=rectangle]{south east}
\inheritanchor[from=rectangle]{base}
\inheritanchor[from=rectangle]{base west}
\inheritanchor[from=rectangle]{base east}
\inheritanchor[from=rectangle]{mid}
\inheritanchor[from=rectangle]{mid west}
\inheritanchor[from=rectangle]{mid east}
\inheritanchor[from=rectangle]{text}
\inheritbackgroundpath[from=rectangle]
\inheritanchorborder[from=rectangle]
\beforebackgroundpath{%
\pgfmathsetcount\pgfutil@tempcnta{\pgfkeysvalueof{/pgf/envelope angle}}%
\pgfsetcornersarced{\pgfpoint{\pgfkeysvalueof{/pgf/envelope radius}}{\pgfkeysvalueof{/pgf/envelope radius}}}%
\pgfmathtan@{\the\pgfutil@tempcnta}%
\let\pgf@sh@envelope@tan\pgfmathresult
\pgfmathcot@{\the\pgfutil@tempcnta}%
\let\pgf@sh@envelope@cot\pgfmathresult
%
\pgfpointadd{\northeast}{\pgfpointscale{-1}{\pgfpoint{\pgfkeysvalueof{/pgf/outer xsep}}{\pgfkeysvalueof{/pgf/outer ysep}}}}%
\pgf@xa=\pgf@x
\pgf@ya=\pgf@y
\pgf@process{\pgfpointadd{\southwest}{\pgfpoint{\pgfkeysvalueof{/pgf/outer xsep}}{\pgfkeysvalueof{/pgf/outer ysep}}}}%
\pgf@xb=\pgf@x
\pgf@yb=\pgf@y
\pgf@xc=.5\pgf@xa
\advance\[email protected]\pgf@xb
\pgf@yc=.5\pgf@ya
\advance\[email protected]\pgf@yb
%
\pgfpathmoveto{\pgfqpoint{\pgf@xa}{\pgf@ya}}%
\pgfpathlineto{\pgfpointadd{\pgfqpoint{\pgf@xa}{\pgf@ya}}{\pgfqpoint{-\pgf@xc}{-\pgf@sh@envelope@tan\pgf@xc}}}
\pgfpathlineto{\pgfqpoint{\pgf@xb}{\pgf@ya}}%
%
\pgfsetcornersarced{\pgfpointorigin}
\pgfpathmoveto{\pgfqpoint{\pgf@xb}{\pgf@yb}}%
\pgfpathlineto{\pgfpointadd{\pgfqpoint{\pgf@xb}{\pgf@yb}}{\pgfqpoint{\pgf@sh@envelope@cot\pgf@yc}{\pgf@yc}}}
\pgfpathmoveto{\pgfpointadd{\pgfqpoint{\pgf@xa}{\pgf@yb}}{\pgfqpoint{-\pgf@sh@envelope@cot\pgf@yc}{\pgf@yc}}}
\pgfpathlineto{\pgfqpoint{\pgf@xa}{\pgf@yb}}%
\pgfusepath{stroke}%
}
}
\makeatother
\tikzset{every envelope node/.style={draw}}
\fboxsep=-\fboxrule % only used for a tight \fbox! Don't use in document
\begin{document}
\tikz \node[envelope] {\fbox{\TeX t}};
\tikz[inner xsep=0pt]\node[envelope] {\fbox{\TeX t}};
\tikz[inner ysep=0pt]\node[envelope] {\fbox{\TeX t}};
\tikz[inner sep=0pt] \node[envelope] {\fbox{\TeX t}};
\end{document}
