tikz -- using the remaining space of a line of text for squarepattern

Question

For my math-lessons I'm searching for an easy way to fill the remaining space of a line with a squarepattern. There are some disadvantages with leaders (alignment, see autofill with square-pattern (leaders vs. tikz)), so I used the explanations in Is there a way to measure the remaining space of a line of text?.

\documentclass{article}

\usepackage{tikzpagenodes}
\usepackage{etoolbox}

\usetikzlibrary{calc}       

\newlength{\whatsleft}
\newcommand{\measureremainder}[2]{%
    \begin{tikzpicture}[overlay,remember picture]
    % Measure distance to right text border
    \path let \p0 = (0,0), \p1 = (current page text area.east) in
    [/utils/exec={\pgfmathsetlength#1{floor((\x1-\x0)/#2)*#2}\global#1=#1}];
    \end{tikzpicture}%
}

\newcommand{\mysquarefill}[4][r]{%
    \measureremainder{\whatsleft}{#2}%
    \ifstrequal{#1}{l}{}{\hfill}%
    \lower#4\hbox{\begin{tikzpicture}%
    \draw[step=5mm,color=gray](0,0) grid (\whatsleft,#3);
    \end{tikzpicture}}%
    \ifstrequal{#1}{c}{\hfill\mbox{}}{}%
}   


\begin{document}

\begin{itemize}
\item $\frac{8}{15} + \frac{7}{12}+ \frac{5}{12} +2=$\mysquarefill[l]{5mm}{10mm}{4mm}
\item $\frac{3}{4}$ von $ \frac{2}{5}=$\mysquarefill[r]{5mm}{15mm}{7mm}
\item $\frac{15}{28}\cdot\frac{14}{30}=$\mysquarefill[r]{5mm}{10mm}{4mm}
\end{itemize}

\end{document}

This produces:

Now I'd like to simplify the code and especially combine the two macros. How do I use something like

\draw[step=5mm,color=gray](0,0) grid (floor((x-coordinate-of(current page text area.east) - x-coordinate-of(0,0))/#2)*#2,#3);

with #2=size of squares and #3=height of squareblock?

And is there an easier solution for the raggedleft/raggedright/center-mechanism?

Answer 1

I fail to see what your actual question is. (Why is @frougon's answer not satisfiable) (You mentioned alignment. Of what? Horizontally or vertically? Only you know what you want.)

Anyway, I propose the following construction that uses TikZ to draw squares and uses \leaders to fill in spaces. If you want to customize squares, play with TikZ. If you want to align properly, play with TeX. Have fun.

\documentclass{article}

\usepackage{tikz}

\begin{document}

\newbox\astackofsquares
\def\mysquarefill#1#2{
    \setbox\astackofsquares=\hbox{%
        \tikz[x=#1,y=#1,baseline=#1*#2/2-.5ex]{
            \path(0,0)(1,#1*#2);
            \begin{pgfinterruptboundingbox}
                \draw foreach\i in{1,...,#2}{(0,\i-1)rectangle(1,\i)};
            \end{pgfinterruptboundingbox}
        }%
    }
    \leaders\copy\astackofsquares\hfill\hbox{}
}

\begin{itemize}
    \item $\frac{8}{15}+\frac{7}{12}+\frac{5}{12} +2=$\mysquarefill{5mm}{2}
    \item $\frac{3}{4}$ von $\frac{2}{5}=$\mysquarefill{5mm}{3}
    \item $\frac{15}{28}\cdot\frac{14}{30}=$\mysquarefill{5mm}{4}
\end{itemize}

\end{document}

centered version

replace \leaders by \cleaders.

flush left version

I propose using a clip instead of doing arithmetics.

\documentclass{article}

\usepackage{tikzpagenodes}
\usepackage{showframe}\def\ShowFrameColor{\color{yellow}}

\begin{document}

\def\quarefillleft#1#2{
    \tikz[remember picture,x=#1,y=#1,baseline=#1*#2/2-.5ex]{
        \path(0,0)(0,#1*#2);
        \begin{pgfinterruptboundingbox}
            \clip(-1,-1)rectangle(current page text area.north east);
            \draw(0,0)grid[step=#1](20cm,#2);
        \end{pgfinterruptboundingbox}
    }
}
\begin{itemize}
    \item $\frac{8}{15}+\frac{7}{12}+\frac{5}{12} +2=\quarefillleft{5mm}{2}$
    \item $\frac{3}{4}$ von $\frac{2}{5}=\quarefillleft{4mm}{3}$
    \item $\frac{15}{28}\cdot\frac{14}{30}=\quarefillleft{3mm}{4}$
\end{itemize}

\end{document}