I'm new to LaTeX and I would like to put a semi-transparent text box behind some text on a title page, similar to what is found here: https://www.overleaf.com/articles/clustering-the-interstellar-medium/mtthgyyfrdkn#.VbTxrZNVK1E. My title page has an image as the background.
I have tried using their code, but was unsuccessful. I also tried using the package mdframed (such as from one of the answers here: How to put a framed box around text + math environment), but I could not make this show the background partially through it.
Below is a template of what I have done for my title page:
\documentclass{article}
\usepackage{eso-pic}
\usepackage{graphicx}
\usepackage{bmpsize}
\usepackage{color}
\newcommand\BackgroundPic{%
\put(0, 0){%
\parbox[b][\paperheight]{\paperwidth}{%
\vfill
\centering
\includegraphics[width=\paperwidth, height = \paperheight,%
keepaspectratio]{desired_background_image.png}%
\vfill
}}}
\begin{document}
\pagenumbering{gobble}
\AddToShipoutPicture*{\BackgroundPic}
\centering
\vspace*{0.5cm}
\huge\textcolor{magenta}{\textbf{Some large title}}
\\
\vspace*{0.5cm}
\large\textcolor{magenta}{Author Name}
\\
\vspace*{11cm}
\begin{flushright}
\small\textcolor{magenta}{Image Credit: Some Source}
\\
\end{flushright}
\end{document}
I would like the text "Some large title" and "Author Name" to have either a magenta or cyan background, with the text either being black, cyan, or magenta (undecided which at this point).
I do not want the text at the bottom right ("Image Credit: Some Source") to have a colored text box behind it.
I may also want to generalize it and have the title and author name separated by more than 0.5cm, in which case I may want to have two different text boxes behind each set of text (not sure how this would turn out yet).
Any suggestions to accomplish this would be greatly appreciated!