A friend sent me a file in LaTeX that she had received. When compiling it, one of the equations had a strange black rectangle:
The file was about 20 pages long. After minimizing and minimizing the file, I got this simplified version:
\documentclass[12pt]{article}
\usepackage[table]{xcolor}
\begin{document}
\centering
Some initial text.
\[
\begin{array}{c}
\rowcolor{red}
1 + 2 = 3 \\
\rowcolor{green}
1 + 2 = 3 \\
\rowcolor{blue}
\end{array}
\]
Some random two pages of text here \\
just to make debugging difficult.
\[
\left\{
\begin{array}{rrrrrrr}
2x &+& y &+& 4z &=& 0\\
x &+& 6y &+& 7z &=& 0\\
\end{array}
\right.
\]
Some final text.
\end{document}
Can you spot the error? In case you can't mentally compile LaTeX, the result is:
Now, is it easier to find the error?
[spoiler alert]
Well, the problem is in the previous table, it has the declaration of the color of the “last” row that does not exist. In the original version, it was a commented row, making it more difficult to spot. Moreover, between one table and the equations system there were one or two pages, making it more difficult to see that the error was actually caused by something that was much earlier than the position where it appeared.
\[
\begin{array}{c}
\rowcolor{red}
1 + 2 = 3 \\
\rowcolor{green}
1 + 2 = 3 \\
\rowcolor{blue} % <---- the error is here
\end{array}
\]
The strangest thing is that you get a black rectangle instead of a blue rectangle. I suppose some flag is set that says that there is something interesting in the next cell, but the color is reset and that is why it is black. I've been looking at the xcolor package code, but my LaTeX-Fu is not strong enough. (It is not even clear to me if this is classified as a bug or not.) And furthermore, there is a workaround that is not to write LaTex with errors.
Bonus: The error is in the first part, so with a trivial change in the second part we can get a matrix or table with a strange black cell.
\begin{center}
\begin{tabular}{|c|c| c|}
\hline
a & b & c \\
\hline
$1$ & $2$ & $3$ \\
\hline
\end{tabular}
\end{center}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持 码农网
猜你喜欢:
本站部分资源来源于网络，本站转载出于传递更多信息之目的，版权归原作者或者来源机构所有，如转载稿涉及版权问题，请联系我们。
Search User Interfaces
Marti A. Hearst / Cambridge University Press / 2009-9-21 / USD 59.00
搜索引擎的本质是帮助用户更快、更方便、更有效地查找与获取所需信息。在不断改进搜索算法和提升性能（以技术为中心）的同时，关注用户的信息需求、搜寻行为、界面设计与交互模式是以用户为中心的一条并行发展思路。创新的搜索界面及其配套的交互机制对一项搜索服务的成功来说是至关重要的。Marti Hearst教授带来的这本新作《Search User Interfaces》即是后一条思路的研究成果，将信息检索与人......一起来看看 《Search User Interfaces》 这本书的介绍吧!
