如何绘制如下图所示的正方形图形

Question

由于链接的示例仅适用于 TiKZ，因此这里有一个简单的方法可以将方格纸添加到任何元帖子图形。

这是使用以下源生成的，并经过编译lualatex：

\documentclass[border=5mm]{standalone}
\usepackage{luamplib}
\begin{document}
\mplibtextextlabel{enable}
\begin{mplibcode}
input graphpaper
beginfig(1);

    path xx, yy, ff;

    xx = 42 left -- 377 right;
    yy = 21 down -- 233 up;


    ff = (20, 20) {right} .. (300, 200) {dir 10};

    drawarrow xx;
    drawarrow yy;

    draw ff withcolor 2/3 red;

    add_background_grid(1cm, 3/4 white);
    add_background_grid(1mm, 7/8 white); 

endfig;
\end{mplibcode}
\end{document}

该add_background_grid宏定义如下：

vardef add_background_grid(expr s, c) = 
    save B, C;
    path B; B = bbox currentpicture;
    picture C; C = currentpicture;
    currentpicture := nullpicture;

    for x = s step s until floor xpart urcorner B:
        draw (x, ceiling ypart llcorner B) -- (x, floor ypart urcorner B) withcolor c;
    endfor
    for x = 0 step -s until ceiling xpart llcorner B:
        draw (x, ceiling ypart llcorner B) -- (x, floor ypart urcorner B) withcolor c;
    endfor
    for y = s step s until floor ypart urcorner B:
        draw (ceiling xpart llcorner B, y) -- (floor xpart urcorner B, y) withcolor c;
    endfor
    for y = 0 step -s until ceiling ypart llcorner B:
        draw (ceiling xpart llcorner B, y) -- (floor xpart urcorner B, y) withcolor c;
    endfor
    draw C;
enddef;

我已将其保存为graphpaper.mp并使用input graphpaper第一个示例顶部的行。

其工作原理是测量当前图片的边界框的大小；擦除当前图片；绘制网格（从原点开始）；然后在顶部绘制原始图片的保存副本。

Answer 1