add appdata screenshot resources

appdata/template.tex

@@ -0,0 +1,60 @@
+\documentclass[varwidth=true, crop, border=5pt]{standalone}
+
+% Packages
+\usepackage{amsmath}
+\usepackage{amssymb}
+
+% for storing in memory verbatim content to be reused later
+\usepackage{scontents}
+
+% Blank formula checking
+\usepackage{ifthen}
+\newlength{\pheight}
+
+% Color support
+\usepackage{xcolor}
+\definecolor{xpp_font_color}{HTML}{%%XPP_TEXT_COLOR%%}
+
+\usepackage{pgfplots}
+
+%for defining commands
+\usepackage{xargs}
+
+% for drawing and plotting
+\usepackage{pgfplots}
+\pgfplotsset{compat=newest} % Allows to place the legend below plot
+\newcommandx{\graph}[3][1=,2=]{
+    \begin{tikzpicture}
+    \begin{axis}[xlabel=$x$,ylabel=$y$, axis lines=center,samples=100, #2]
+    \addplot[#1]{#3};
+    \end{axis}
+    \end{tikzpicture}
+}
+
+% for code highlighting
+\usepackage{tikz}
+\usepackage{listings}
+\lstset{language=C++,
+	basicstyle=\ttfamily,
+	keywordstyle=\color{blue}\ttfamily,
+	stringstyle=\color{red}\ttfamily,
+	commentstyle=\color{green}\ttfamily,
+	morecomment=[l][\color{magenta}]{\#}
+}
+
+% User input
+\begin{scontents}[store-env=preview]
+	\( 
+	\displaystyle
+    %%XPP_TOOL_INPUT%%
+	\)
+\end{scontents}
+
+\begin{document}
+  % Check if the formula is empty
+  \settoheight{\pheight}{\getstored[1]{preview}}
+  \ifthenelse{\pheight=0}{\GenericError{}{xournalpp:blankformula}{}{}}
+
+  % Render the user input
+  \textcolor{xpp_font_color}{\getstored[1]{preview}}
+\end{document}