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将节点放置在图像中给定像素值的位置

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将节点放置在图像中给定像素值的位置

我有一张 4903 × 314 像素的 PDF 图像。如何将节点放置在图像中的 (3903, 251) 位置？图像本身将缩放以适合页面宽度。

答案1

编辑：为多个节点添加第二个宏

描述\PlaceInImageAt： 中的第一个参数 (#1,#2)应该是图像的像素大小，第二个参数(#4,#5)应该是您想要放置节点的像素。#3应该是要使用的图像，可选的[#6]是您可以提供的选项\node，最后#7是该节点的内容。size 参数(#1,#2)是可选的。如果未指定，则使用。您可以通过更改中的命令(100,100)将图像缩放到您想要的任何尺寸（甚至不成比例）。\includegraphics#3

描述\MultiPlaceInImageAt： 前三个参数相同。可选参数接受[#4]应传递给每个节点的选项。最后一个参数是一个逗号分隔的列表。每个节点都应使用以下方案括在括号中 {<x>,<y>=[<options>]<content>}。

\documentclass[]{article}

\usepackage{tikz,graphicx}
\makeatletter
\newbox\PlaceInImageAtbox
\newcommand\PlaceInImageAt{}% just to check whether it is already defined
\def\PlaceInImageAt
  {%
    \@ifnextchar(
      {\PlaceInImageAt@i}
      {\PlaceInImageAt@i(100,100)}
  }
\def\PlaceInImageAt@i(#1,#2)#3(#4,#5)%
  {%
    \@ifnextchar[
      {\PlaceInImageAt@ii{#1}{#2}{#3}{#4}{#5}}
      {\PlaceInImageAt@ii{#1}{#2}{#3}{#4}{#5}[]}%
  }
\def\PlaceInImageAt@ii#1#2#3#4#5[#6]#7%
  {%
    \setbox\PlaceInImageAtbox\hbox{#3}%
    \begin{tikzpicture}
      \draw[use as bounding box] node at (0,0) {\usebox\PlaceInImageAtbox};
      \pgfmathsetmacro\PlaceInImageAtx{(#4 - #1/2) * (\wd\PlaceInImageAtbox/#1)}
      \pgfmathsetmacro\PlaceInImageAty{(#5 - #2/2) * (\ht\PlaceInImageAtbox/#2)}
      \node[#6] at (\PlaceInImageAtx pt,\PlaceInImageAty pt) {#7};
    \end{tikzpicture}%
  }
\def\MultiPlaceInImageAt
  {%
    \@ifnextchar(
      {\MultiPlaceInImageAt@i}
      {\MultiPlaceInImageAt@i(100,100)}
  }
\def\MultiPlaceInImageAt@i(#1,#2)#3%
  {%
    \@ifnextchar[
      {\MultiPlaceInImageAt@ii{#1}{#2}{#3}}
      {\MultiPlaceInImageAt@ii{#1}{#2}{#3}[]}%
  }
\def\MultiPlaceInImageAt@ii#1#2#3[#4]#5%
  {%
    \setbox\PlaceInImageAtbox\hbox{#3}%
    \begin{tikzpicture}
      \draw[use as bounding box] node at (0,0) {\usebox\PlaceInImageAtbox};
      \@for\arg@MultiPlace:={#5}\do
        {%
          \expandafter
          \MultiPlaceInImageAt@each\arg@MultiPlace\@rgend{#1}{#2}{#4}
        }
    \end{tikzpicture}
  }
\def\MultiPlaceInImageAt@each#1,#2=%
  {%
    \@ifnextchar[
      {\MultiPlaceInImageAt@each@i{#1}{#2}}
      {\MultiPlaceInImageAt@each@i{#1}{#2}[]}%
  }
\def\MultiPlaceInImageAt@each@i#1#2[#3]#4\@rgend#5#6#7%
  {%
    \pgfmathsetmacro\PlaceInImageAtx{(#1 - #5/2) * (\wd\PlaceInImageAtbox/#5)}
    \pgfmathsetmacro\PlaceInImageAty{(#2 - #6/2) * (\ht\PlaceInImageAtbox/#6)}
    \node[#7,#3] at (\PlaceInImageAtx pt, \PlaceInImageAty pt) {#4};
  }
\makeatother

\begin{document}
\PlaceInImageAt(4903,314){\includegraphics{example-image}}
  (3903,251)[draw,circle,red]{foo}

\PlaceInImageAt{\includegraphics[width=5cm,height=2cm]{example-image}}
  (50,50)[draw,circle,red]{foo}

\MultiPlaceInImageAt{\includegraphics[scale=0.5]{example-image-a}}
  [red]% option for each node
  {{20,20=[blue]a},{40,40={b}},{60,60={c}},{80,80={d}}}
\end{document}

在此处输入图片描述

答案2

下面是一个代码，如果您仅将图形缩放到\textwidth（使得垂直缩放成比例），则可以执行此操作。

更新：写了一个小宏，可以重复使用。

\documentclass{article}
\usepackage{tikz}
\newcommand{\PlaceNode}[5][]{
\pgfmathsetmacro{\myx}{(#2-4903/2)*(\the\textwidth/4903)}
\pgfmathsetmacro{\myy}{(#3-314/2)*(\the\textwidth/4903)}
\node[#1] (#4) at  (\myx pt,\myy pt) {#5};
}
\begin{document}
\begin{tikzpicture}
\node at (0,0){\includegraphics[width=\textwidth]{example-image-a}};

\PlaceNode[draw,circle,red]{3903}{251}{first}{}
\PlaceNode[draw,circle,blue]{3703}{151}{second}{}

\end{tikzpicture}
\end{document}

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