[Tex/LaTex] Textblock gives grey background which I cannot change

colortextpos

Please could someone suggest what I am doing wrong? I keep getting text boxes with a grey background, even when I try to change the text block colour. I used an example from a popular book to try to get this right but I still get black lines around text boxes and grey background which does not appear in the book Learning LaTeX.

\documentclass[a0]{a0poster}
\usepackage[absolute, overlay]{textpos}
\usepackage{amsfonts, amsmath}
\usepackage[demo]{graphicx}
\usepackage{color}
\usepackage{tcolorbox}
\graphicspath{ {LiteratureReview/}}
\TPGrid[10mm, 10mm]{48}{24}
\TPMargin{12.5mm}
\parindent=0pt
\definecolor{White}{cmyk}{0,0,0,0}
\definecolor{Lilac}{cmyk}{0.09,0.12,0,0}
\definecolor{Purple}{cmyk}{0.5,0.3,0,0}
\definecolor{Lemon}{cmyk}{0,0,0.1,0}
\begin{document}
\title{\Huge  Online Monitoring Systems for the Stability Analysis}
\date{}\author{\LARGE CJ}

%\begin{tcolorbox}[height=0.85\textheight, width=\textheight, arc=0mm]
%\end{tcolorbox}

\pagecolor{Lilac}

\begin{figure}
\includegraphics[height=150mm]{original_data}
\caption{original dynamic response data for contingencies DS01 (top) and DS02}
\label{original_data}
\end{figure}



\textblockcolour{White}
\begin{textblock}{0}(0,0)
%\begin{figure}
\includegraphics[height=50mm]{Mcrlogo}
%\end{figure}
%\begin{figure}
\includegraphics[height=50mm]{EPSRC}
%\end{figure}
\end{textblock}

\end{document}

Best Answer

The first argument passed to the textblock environment gives the horizontal width of the block. You have requested 0, so the block has zero width. Hence, you have a colour block of zero width, which is visibly indistinguishable from a non-colour block of somewhat greater width.

I suspect your blocks are actually lilac rather than grey, if you've compiling code similar to that posted in the question. That is, you're just seeing the colour you've set for the page.

Changing the value to set a non-zero width solves the problem.

\documentclass{article}
\usepackage[absolute,overlay]{textpos}
\usepackage{xcolor}
\parindent=0pt
\begin{document}
\title{Online Monitoring Systems for the Stability Analysis}
\date{}\author{CJ}
\maketitle

\pagecolor{yellow}

\textblockcolour{cyan}
\begin{textblock}{10}(0,0)
  abc
\end{textblock}
\end{document}

[I minimised your example somewhat because I couldn't compile it as posted and, once I got it compiling, I didn't know what was responsible as I'm not familiar with textpos. Hence, my result is rather more lurid than your white-on-lilac might be and my paper's a bit smaller.]

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[Tex/LaTex] Change float background colour

Looking at the color documentation, it says that \colorbox uses the parameters \fboxrule and \fboxsep. Maybe try

\setlength\fboxrule{0pt}
\setlength\fboxsep{0pt}

before using the \colorbox.

Edit:
It seems to work for me. The space between the rules isn't added by the \colorbox, but by the ruled float style. One possibility would be to design a new float style and then use \restylefloat from the float package to change the style of the algorithm floats. Rather than do that, I just added some kerns.

I'm becoming less and less convinced this is the right way to do these things. It feels like we're just piling hack on top of hack here. I feel like this is partly due to using LyX, but I have zero experience with it, so I'm not positive.

% Resize figures that are too wide for the page.
\let\oldincludegraphics\includegraphics
\renewcommand\includegraphics[2][]{%
  \graphicsformat{%
    \oldincludegraphics[width=\ScaleIfNeeded]{#2}%
  }%
}

% Change the background colour of algorithm boxes
\let\oldalgorithm\algorithm
\let\endoldalgorithm\endalgorithm
\renewenvironment{algorithm}[1][htbp]{
  \let\graphicsformat\justifiedandcolored
  \oldalgorithm[#1]
}%
  {\endoldalgorithm}

\def\justifiedandcolored#1{%
  \setlength\fboxrule{0pt}%
  \setlength\fboxsep{0pt}%
  \kern-2pt
  \colorbox{sourcecolour}{%
    \hbox to\linewidth{#1}%
  }%
  \par
  \kern-2pt
}

% Centre graphics within non-Algorithm floats.
\let\graphicsformat\centering

[Tex/LaTex] Change background color in metapost

Here's a receipe for drawing an image whose dimensions aren't known in advance on a background that scales to the image's final bounding box:

Draw the image.
Save the image in a picture variable.
Measure the picture's bounding box.
Draw the background.
Re-draw the original image on top of the background.

Here's an example followed by some random notes:


beginfig(1);
  %
  % Draw random picture.
  %
  pair p,q;
  for i = 1 upto 20:
    p := (uniformdeviate 200, uniformdeviate 200);
    q := (uniformdeviate 200, uniformdeviate 200);
    draw p--q withpen pencircle scaled 2 withcolor red;
  endfor
  %
  % Solution starts here.
  %
  % Save picture in variable pic for later reference.
  picture pic;
  pic := currentpicture;
  % Clear currentpicture to avoid outputting the picture twice.
  currentpicture := nullpicture;
  % Fill a rectangle with pic's bounding box dimensions (plus
  % bboxmargin) with desired background colour.
%  interim bboxmargin := 0;
  fill bbox pic withcolor blue;
  % Draw original picture on top of background.
  draw pic;
endfig;
end

Saving an image in a picture variable can either be done by storing currentpicture in a picture variable or via the image command (see the MetaPost manual for more information). If the currentpicture method is used, like in the example, make sure to clear currentpicture before drawing the background. Otherwise the image is output twice, the first copy being hidden behind the background, bloating the output file.

The bbox command returns a rectangular path corresponding to the bounding box of the picture argument plus a small amount determined by the internal variable bboxmargin (2bp by default).

Internal variables can be modified locally to the current group using the interim statement. That is, if you wrap an assignment to an internal variable in begingroup ... endgroup; the variable's value is restored after the group. Note, beginfig() just starts a group that ends at the corresponding endfig.

Best Answer

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[Tex/LaTex] Change float background colour

[Tex/LaTex] Change background color in metapost

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