让 LaTeX 文档从一种字体慢慢转换为另一种字体

Question

方法 1

我认为，这只是拙劣的模仿，无法达到预期效果。它不是通过演变字体结构来实现的，而是通过两种固定字体之间的渐变机制来实现的。因此，在中间状态中，存在可见的叠加。

通过设置\fadefrom和\fadeto，您可以选择起始和最终目的地，正如我下面所做的三次。目前，结果的字母宽度是两种字体中较宽的字体，因此更改为宽度相差很大的字体效果不佳。

这使用了一种\FadeAfter{<length>}{<text>}语法。

\documentclass{article}
\usepackage{xcolor,stackengine,tikz}
\newcommand\fadefrom{}
\newcommand\fadeto{\textsf}
\newcommand\fade[1]{%
  \edef\antitwo{\the\numexpr100-#2\relax}%
  \ifnum\antitwo>99\relax\def\antitwo{99}\else%
    \ifnum\antitwo<10\relax\edef\antitwo{0\antitwo}\else%
      \ifnum\antitwo<1\relax\def\antitwo{1}\fi\fi\fi%
  \ifnum#2>50\relax
    \stackengine{0pt}%
      {\tikz\node[inner sep=0pt, opacity=1]{%
      \textcolor{black!\antitwo}{\strut\fadeto{#1}}};}%
      {\tikz\node[inner sep=0pt, opacity=1]{\textcolor{black!#2}{\strut\fadefrom{#1}}};}%
      {O}{c}{F}{F}{L}%
  \else%
    \stackengine{0pt}%
      {\tikz\node[inner sep=0pt, opacity=1]{\textcolor{black!#2}{\strut\fadefrom{#1}}};}%
      {\tikz\node[inner sep=0pt, opacity=1]{%
      \textcolor{black!\antitwo}{\strut\fadeto{#1}}};}%
      {O}{c}{F}{F}{L}%
  \fi%
}
%%%
\usepackage{ifthen}
\newcounter{tmpcounter}
\newlength\critlength
\newlength\tmplength
\newcount\mynum
\newcount\myden
\makeatletter
\newcommand\FadeAfter[1]{%
  \critlength=#1\relax%
  \def\cumstring{}\fahelp{#1}{#2}}
\newcommand\fahelp[1]{\fahelper#2 \relax\relax}
\def\fahelper#1 #2\relax{%
  \global\protected@edef\cumstring{\cumstring#1\ }%
  \setbox0=\hbox{\cumstring}%
  \tmplength=.01\critlength\relax%
  \mynum=\wd0\relax%
  \myden=\tmplength\relax%
  \divide\mynum by\myden%
  \setcounter{tmpcounter}{\numexpr100-\the\mynum}%
  \ifnum\thetmpcounter<0\setcounter{tmpcounter}{0}\fi%
  \fadehelperB{\thetmpcounter}#1\relax\ %
    \ifx\relax#2\relax\else\fahelp{\critlength}{#2\relax}\fi%
}
\def\fadehelperB#1#2#3\relax{%
  \fade{#2}{#1}\ifx\relax#3\relax\else\fadehelperB{#1}#3\relax\fi%
}
\makeatother
\parskip 1ex
\begin{document}
\sloppypar
\FadeAfter{10in}{%
Four score and seven years ago our fathers brought forth on this continent, a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal.}

\def\fadefrom{\ttfamily}
\def\fadeto{\fontfamily{pcr}\selectfont}
\FadeAfter{24in}{%
Now we are engaged in a great civil war, testing whether that nation, or any nation so conceived and so dedicated, can long endure. We are met on a great battle-field of that war. We have come to dedicate a portion of that field, as a final resting place for those who here gave their lives that that nation might live. It is altogether fitting and proper that we should do this.}

\def\fadefrom{}
\def\fadeto{\fontfamily{ppl}\selectfont}
\FadeAfter{60in}{%
But, in a larger sense, we can not dedicate {{---}} we can not consecrate {{---}} we can not hallow {{---}} this ground. The brave men, living and dead, who struggled here, have consecrated it, far above our poor power to add or detract. The world will little note, nor long remember what we say here, but it can never forget what they did here. It is for us the living, rather, to be dedicated here to the unfinished work which they who fought here have thus far so nobly advanced. It is rather for us to be here dedicated to the great task remaining before us {{---}} that from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion {{---}} that we here highly resolve that these dead shall not have died in vain {{---}} that this nation, under God, shall have a new birth of freedom {{---}} and that government of the people, by the people, for the people, shall not perish from the earth.}
\end{document}

第一段从罗马字体淡化为 CM 的无衬线字体。
第二段从 CM 淡入\ttfamily到 PCR（Courier）字体。
第三段从 CM roman 逐渐变为 Palatino roman。

下面，我尝试

\newcommand\fadefrom{\edef\tmp{\the\numexpr\antitwo/3\relax}%
  \ifnum\tmp<10\edef\tmp{0\tmp}\fi%
  \scalebox{1.\tmp}[1]}
\newcommand\fadeto{\edef\tmp{\the\numexpr\antitwo/2\relax}%
  \ifnum\tmp<10\edef\tmp{0\tmp}\fi%
  \sffamily\scalebox{1.\tmp}[1]}

我可以实现结果的逐步延伸。

飞涨：

方法 2

通过替换\fadehelperB宏，并使用像 Bruno 的\slantbox(剪切变换一个“盒子”) 和 Malipivo 的 pdf 特刊 (TikZ：文本周围有光晕？），我可以生成不涉及叠加字体的结果。但是，它并不代表两种任意字体之间的真正转换。相反，它以 3 种方式同时连续地转换单个字体：

改变水平拉伸；
改变字体粗细；以及
改变字体倾斜度

在下面的例子中，字体轮廓厚度（pdfliteral 参数）从 0.66 变为 0；水平拉伸从 1.75 变为 1；倾斜度从 0.25 变为 0。

\documentclass{article}
\usepackage{xcolor,tikz}
%%%
\usepackage{ifthen}
\newcounter{tmpcounter}
\newlength\critlength
\newlength\tmplength
\newcount\mynum
\newcount\myden
\makeatletter
\newcommand\FadeAfter[2]{%
  \critlength=#1\relax%
  \def\cumstring{}\fahelp{#1}{#2}}
\newcommand\fahelp[2]{\fahelper#2 \relax\relax}
\def\fahelper#1 #2\relax{%
  \global\protected@edef\cumstring{\cumstring#1\ }%
  \setbox0=\hbox{\cumstring}%
  \tmplength=.01\critlength\relax%
  \mynum=\wd0\relax%
  \myden=\tmplength\relax%
  \divide\mynum by\myden%
  \setcounter{tmpcounter}{\numexpr100-\the\mynum}%
  \ifnum\thetmpcounter<1\setcounter{tmpcounter}{1}\fi%
  \fadehelperB{\thetmpcounter}#1\relax\ %
    \ifx\relax#2\relax\else\fahelp{\critlength}{#2\relax}\fi%
}
\def\fadehelperB#1#2\relax{%
  \def\tmp{\the\numexpr2*#1/3\relax}% FONT OUTLINE THICKNESS VARIES FROM .66 TO 0
  \ifnum\tmp<1\relax\def\tmp{1}\fi%
  \ifnum\tmp<10\relax\def\thickness{.0\tmp}\else\def\thickness{.\tmp}\fi%
  \edef\tmp{\the\numexpr3*#1/4\relax}% H-STRETCH VARIES FROM 1.75 TO 1
  \ifnum\tmp<10\edef\tmp{0\tmp}\fi%
  \edef\tmpC{\the\numexpr#1/4\relax}% SLANT VARIES FROM .25 TO 0
  \ifnum\tmpC<10\edef\tmpC{0\tmpC}\fi%
  \scalebox{1.\tmp}[1]{\slantbox[.\tmpC]{\outline{#2}}}}
%%% MALIPIVO's PDF SPECIAL TO CHANGE FONT OUTLINE THICKNESS/COLOR
% https://tex.stackexchange.com/questions/18472/tikz-halo-around-text/169549#169549
\input pdf-trans
\newbox\qbox
\def\usecolor#1{\csname\string\color@#1\endcsname\space}
\newcommand\bordercolor[1]{\colsplit{1}{#1}}
\newcommand\fillcolor[1]{\colsplit{0}{#1}}
\newcommand\outline[1]{\leavevmode%
  \def\maltext{#1}%
  \setbox\qbox=\hbox{\maltext}%
  \boxgs{Q q 2 Tr \thickness\space w \fillcol\space \bordercol\space}{}%
  \copy\qbox%
}
\makeatother
\newcommand\colsplit[2]{\colorlet{tmpcolor}{#2}\edef\tmp{\usecolor{tmpcolor}}%
  \def\tmpB{}\expandafter\colsplithelp\tmp\relax%
  \ifnum0=#1\relax\edef\fillcol{\tmpB}\else\edef\bordercol{\tmpC}\fi}
\def\colsplithelp#1#2 #3\relax{%
  \edef\tmpB{\tmpB#1#2 }%
  \ifnum `#1>`9\relax\def\tmpC{#3}\else\colsplithelp#3\relax\fi
}
\bordercolor{black}
\fillcolor{black}
%%% BRUNO's \slantbox
% https://tex.stackexchange.com/questions/63179/shear-transform-a-box/63188#63188
\newsavebox\foobox
\newcommand{\slantbox}[2][.2]{\mbox{%
        \sbox{\foobox}{#2}%
        \hskip\wd\foobox
        \pdfsave
        \pdfsetmatrix{1 0 #1 1}%
        \llap{\usebox{\foobox}}%
        \pdfrestore
}}
%%%
\parskip 1ex
\begin{document}
\sloppypar
\FadeAfter{10in}{%
Four score and seven years ago our fathers brought forth on this continent, a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal.}

\FadeAfter{24in}{%
Now we are engaged in a great civil war, testing whether that nation, or any nation so conceived and so dedicated, can long endure. We are met on a great battle-field of that war. We have come to dedicate a portion of that field, as a final resting place for those who here gave their lives that that nation might live. It is altogether fitting and proper that we should do this.}

\FadeAfter{60in}{%
But, in a larger sense, we can not dedicate {{---}} we can not consecrate {{---}} we can not hallow {{---}} this ground. The brave men, living and dead, who struggled here, have consecrated it, far above our poor power to add or detract. The world will little note, nor long remember what we say here, but it can never forget what they did here. It is for us the living, rather, to be dedicated here to the unfinished work which they who fought here have thus far so nobly advanced. It is rather for us to be here dedicated to the great task remaining before us {{---}} that from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion {{---}} that we here highly resolve that these dead shall not have died in vain {{---}} that this nation, under God, shall have a new birth of freedom {{---}} and that government of the people, by the people, for the people, shall not perish from the earth.}
\end{document}

Answer 1