TikZ - 是否可以对图像应用转换？

Question

是否可以将 TikZ 变换应用于现有图像（复杂）以获得镜头的预定失真效果，例如这两个？

Answer 1

我试图理解在网上找到的一些公式。

1. 划分X和是坐标值等于某个值。
2. 计算到该点的距离。
3. 计算 1 + 因子 * 距离X和是价值。

我没有通过使用图像（ ）或仅仅是节点\includegraphics中的纯文本获得任何有趣的结果。\pgftext

代码

\documentclass[tikz]{standalone}
\usepgfmodule{nonlineartransformations}
\pgfset{
  barrel x factor/.initial=.3,
  barrel y factor/.initial=.3,
  barrel factor/.style={
    /pgf/barrel x factor/.evaluated={#1},
    /pgf/barrel y factor/.evaluated={#1}},
  barrel  width/.initial  =5cm,
  barrel height/.initial  =5cm,
  barrel size/.style={
    /pgf/barrel width/.evaluated={#1},
    /pgf/barrel height/.evaluated={#1}}}
\makeatletter
\newcommand*\pgfbarreldistortion{%
  % xa, ya = original point
  \pgf@xa=\pgf@x
  \pgf@ya=\pgf@y
  % divide lengths by something (make it smaller)
  \pgfmathdivide@{\pgf@xa}{\pgfkeysvalueof{/pgf/barrel width}}%
  \let\barrel@x\pgfmathresult
  \pgfmathdivide@{\pgf@ya}{\pgfkeysvalueof{/pgf/barrel height}}%
  \let\barrel@y\pgfmathresult
  %
  % calculate some radius
  \pgfmathveclen@{\barrel@x}{\barrel@y}%
  \let\barrel@radius\pgfmathresult
  %
  % 1 + factor * radius (but quicker)
  \pgfmathmultiply@{\pgfkeysvalueof{/pgf/barrel x factor}}{\barrel@radius}%
  \pgfmathadd@{\pgfmathresult}{1}%
  \pgf@x=\pgfmathresult\pgf@xa
  \pgfmathmultiply@{\pgfkeysvalueof{/pgf/barrel y factor}}{\barrel@radius}%
  \pgfmathadd@{\pgfmathresult}{1}%
  \pgf@y=\pgfmathresult\pgf@ya
}
\makeatother
\tikzset{
  barrel/.code=\pgftransformnonlinear{\pgfbarreldistortion},
}
\begin{document}
\tikz{
  \draw [help lines]    (-5,-5) grid (5,5);
  \draw [barrel, thick] (-5,-5) grid (5,5);
}
\tikz[barrel factor=-.1]{
  \draw [help lines]    (-5,-5) grid (5,5);
  \draw [barrel, thick] (-5,-5) grid (5,5);
}
\end{document}

输出