Scaling tikzpicture to fit on page with caption

Question

I have a full page that I have managed to scale down with a \resizebox. Unfortunately, after I discovered this in a MWE, I put it back in my document and the caption is now in the footer...

How do I account for the caption in my resize box or include the caption within the resize box?

MWE:

\documentclass{article}

\usepackage[letterpaper, margin=0.5in, includefoot]{geometry} % Advanced page geometry configuation

\usepackage{fancyhdr} % Used for header and footer creation
\pagestyle{fancy}
\fancyhf{} % clear all fields
\lfoot{Lorem\\Ipsum}\cfoot{dolor sit\\amet \\ \thepage}\rfoot{Rev. \#\\ \today}

\usepackage{tikz} % Flowcharts

\renewcommand{\headrulewidth}{0.0pt} % removes line at top that comes w/ fancyhdr

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\usepackage{graphicx}
\usepackage{tikz}

\usetikzlibrary{shapes, arrows, positioning, calc, matrix}

% Define block styles
\tikzstyle{state}   = [ rounded rectangle, 
                        draw, 
                        text centered, 
                        minimum height = 3em,
                        minimum width = 6em,
                        inner sep = 5pt
                        ]
\tikzstyle{test}    = [ diamond, 
                        draw, 
                        shape aspect = 2, 
                        inner sep = 0pt,
                        text width = 7em,
                        text centered 
                      ]
\tikzstyle{action}  = [ rectangle, draw,
                        text width = 8em,
                        inner sep = 5pt, 
                        minimum height = 5em
                      ]
\tikzstyle{data}    = [ trapezium, 
                        draw, 
                        trapezium left angle = 60, 
                        trapezium right angle = 120pt,
                        minimum height = 6em, 
                        text width = 5em,
                        inner xsep = 0pt
                       ]
\tikzstyle{line}    = [ draw, -triangle 45 ]

\begin{document}


\begin{figure}[H]

\begin{center}
\resizebox{\textwidth}{\textheight}{%
\input{./flowchart.tex}
}
\caption{\textbf {My Stupid Flowchart} }

\end{center}

\end{figure} 


\end{document}

---

Flowchart.tex:

\resizebox{\textwidth}{\textheight}{%
\begin{tikzpicture}[align = flush center, font = \small]


    % Place nodes
    \matrix [matrix of nodes, column sep = 0.5em, row sep = 1.3em,
                draw, dotted,
                nodes={solid},
                matrix anchor=south east,
                inner sep = 1em,
                ampersand replacement=\&
                ] (state-mtrx)  at (0,0) 
    {            
    |[data] (a)| Lorem ipsum dolor sit amet, c \\        
    |[test] (b)| Lorem ipsum d \\
    |[action] (c)| Lorem ipsum dolor sit amet, consectetur adipiscing\\        
    |[test] (d)| Lorem ipsum dolor  \\         
    |[action] (e)| Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque tempus nisl id  \\   
    |[test] (f)| Lorem ipsum dolor sit amet, \\    
    |[action] (g)| Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque tempus nisl id lectus\\  
    |[action] (h)| Lorem ipsum dolor sit amet, consectetur adipiscing eli \\[1em]
    |[action] (j)| Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque tempus nisl id \\
    [1em]\\
     }; 

    \matrix [matrix of nodes, column sep = 0.5em, row sep = 1.3em,
                nodes = {solid},
                draw, dotted,
                matrix anchor=south west,
                inner xsep = 3em,
                ampersand replacement=\&
                ] (state-send-response) at (0,0) 
    {
    \\
    \\
    \\ 
    \&|[test] (i)| Lorem ipsum dolor? \\    
    \&|[test] (k)| ILorem ipsum dolor sit amet,? \\    
    \&|[action] (l)| Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque \\ [1em]   
    \&|[data] (m)| Lorem ipsum dolor sit amet, consect \\    
    |[state] (n)| Lorem ipsum dolor sit 
    \&|[state] (p)| Lorem ipsum dolor\\   
    }; 

    \node[state, above = of a] (write) {WLorem ipsu};  

    \path [] ([shift={(-3mm, 0)}]state-mtrx.north west) -- ([shift={(-3mm, 0)}]state-mtrx.south west) coordinate(state-line);

    \path let \p1=(state-line), \p2=($ (a)!0.5!(b)$ ) in (\p2) -- node [left, very near end] {Lorem ipsum dolor} (\x1,\y2);
    \path let \p1=(state-line), \p2=($ (c)!0.5!(d)$ ) in (\p2) -- node [left, very near end] {Lorem ipsum dolor sit am} (\x1,\y2);
    \path let \p1=(state-line), \p2=($ (e)!0.5!(f)$ ) in (\p2) -- node [left, very near end] {Lorem ipsum dol} (\x1,\y2);
    \path let \p1=(state-line), \p2=(g) in (\p2) -- node [left, very near end] {Lorem ipsum dolor} (\x1,\y2);
    \path let \p1=(state-line), \p2=(h) in (\p2) -- node [left, very near end] {Lorem ipsum dolo\\Lorem ipsum dol} (\x1,\y2);
    \path let \p1=(state-line), \p2=(j) in (\p2) -- node [left, very near end] {Lorem ipsum dolo} (\x1,\y2);

    \node [above = 0em of state-send-response.north] {Lorem ipsum dolor s};

% Draw edges
    % Dotted separators
    \path [draw, dotted] let \p1=( $(b.south)!0.5!(c.north)$ ), \p2=(state-mtrx.north west), \p3=(state-mtrx.north east) in (\x2, \y1) -- (\x3, \y1);
    \path [draw, dotted] let \p1=( $(d.south)!0.5!(e.north)$ ), \p2=(state-mtrx.north west), \p3=(state-mtrx.north east) in (\x2, \y1) -- (\x3, \y1);
    \path [draw, dotted] let \p1=( $(f.south)!0.5!(g.north)$ ), \p2=(state-mtrx.north west), \p3=(state-mtrx.north east) in (\x2, \y1) -- (\x3, \y1);
    \path [draw, dotted] let \p1=( $(g.south)!0.5!(h.north)$ ), \p2=(state-mtrx.north west), \p3=(state-mtrx.north east) in (\x2, \y1) -- (\x3, \y1);
    \path [draw, dotted] let \p1=( $(h.south)!0.3!(j.north)$ ), \p2=(state-mtrx.north west), \p3=(state-mtrx.north east) in (\x2, \y1) -- (\x3, \y1);


     % left State Paths      
    \path [line] (write) -- (a);

    \path [line] (a) -- (b);

    %% (d) paths - not in order because of reference point (d-no)
    \path [line] (d) -- node [right, near start] {Yes} (e);
    \path [line] (d.east) -- node [above, near start] {No} +(1.5,0)coordinate(d-no) -| (i);

    \path [line] (b) -- node [right, very near start] {Yes} (c);
    \path [line] (b) -| node [above, pos=0.02] {No} (d-no);

    \path [line] (c) -- (d);

    \path [line] (e) -- (f);

    \path [line] let \p1=([shift={(2mm, 0)}]state-mtrx.west), \p2=(f.west) in (\p2) -- node [above, near start] {Yes} (\x1, \y2) |- ( $(h.south)!0.5!(j.north)$ );
    \path [line] (f) -- node [right, near start] {No} (g);

    \path [] (b.east) -- +(1,0)coordinate(copy-no);
    \path [line] (j.south) |- ([shift={(2mm, 2em)}]state-mtrx.south east) -| (d-no);

    \path [line] (g) -- (h);

    \path [line] (h) -- (j);

    % Response State paths
    \path [line] (i.east) -- node [above, near start] {Yes} +(1,0) |- ( $(l.south)!0.3!(m.north)$ );
    \path [line] (i.south) -- node [right] {No} (k);

    \path [line] (k) -- node [right] {Yes} (l);
    \path [line] (k.west) -| node [above, very near start] {No} (n);

    \path [line] (l) -- (m);

    \path [line] (m) -- (p);   

\end{tikzpicture}
}

Answer 1

The following method puts the caption inside a box and measures its height. Then the value for the height of the \resizebox can be calculated.

• In flowchart I have removed the additional \resizebox. Also I have commented the line end after \end{tikzpicture}. We are in horizontal mode, that means that space contributes to the width. Also I have removed the space after\input{./flowchart.tex} for the same reason.

• I have added option showframe for package geometry to show the borders of the text body.

• \resizebox is not too accurate. Therefore I had wrapped the contents in the figure inside an additional \vbox with a small correction inside.

• \hspace{-0.3333em} cancels the inner sep of the left most text node.
  Update: I have moved it to the file flowchart.tex, because it is a property of the flowchart. Just add the following line right before \begin{tikzpicture}:

  \hspace*{-.3333em}% remove left `inner sep` from the leftmost text node
  

• \nointerlineskip prevents additional glue between the picture box and the caption box.

• Update: The flow chart is only scaled, if it overflows the available width or height.

The example file:

\documentclass{article}

\usepackage[showframe,letterpaper, margin=0.5in, includefoot]{geometry} % Advanced page geometry configuation

\usepackage{fancyhdr} % Used for header and footer creation
\pagestyle{fancy}
\fancyhf{} % clear all fields
\lfoot{Lorem\\Ipsum}\cfoot{dolor sit\\amet \\ \thepage}\rfoot{Rev. \#\\ \today}

\usepackage{tikz} % Flowcharts

\renewcommand{\headrulewidth}{0.0pt} % removes line at top that comes w/ fancyhdr

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\usepackage{graphicx}
\usepackage{tikz}

\usetikzlibrary{shapes, arrows, positioning, calc, matrix}

% Define block styles
\tikzstyle{state}   = [ rounded rectangle,
                        draw,
                        text centered,
                        minimum height = 3em,
                        minimum width = 6em,
                        inner sep = 5pt
                        ]
\tikzstyle{test}    = [ diamond,
                        draw,
                        shape aspect = 2, 
                        inner sep = 0pt,
                        text width = 7em,
                        text centered 
                      ]
\tikzstyle{action}  = [ rectangle, draw,
                        text width = 8em,
                        inner sep = 5pt,
                        minimum height = 5em
                      ]
\tikzstyle{data}    = [ trapezium,
                        draw,
                        trapezium left angle = 60,
                        trapezium right angle = 120pt,
                        minimum height = 6em,
                        text width = 5em,
                        inner xsep = 0pt
                       ]
\tikzstyle{line}    = [ draw, -triangle 45 ]

\newsavebox\captionbox
\newsavebox\flowchartbox
\newdimen\flowchartmaxheight
\newcommand*{\maxminipageheight}{%
  \dimexpr\ifdim\height>\textheight\textheight\else\height\fi\relax
}

\begin{document}

\begin{figure}
  \begin{minipage}[b][\maxminipageheight][c]{\textwidth}%
    \sbox\captionbox{%
      \parbox[b]{\textwidth}{%
        \centering
        \caption{\textbf {My Stupid Flowchart}}%
      }%
    }%  
    \sbox\flowchartbox{\input{flowchart}}%
    \pgfmathsetlength{\flowchartmaxheight}{\textheight-\ht\captionbox}%
    \ifdim\ht\flowchartbox>\flowchartmaxheight
      \sbox\flowchartbox{%
        \resizebox{!}{\flowchartmaxheight}{\box\flowchartbox}%
      }%
    \fi 
    \ifdim\wd\flowchartbox>\textwidth
      \sbox\flowchartbox{%
        \resizebox{\textwidth}{!}{\box\flowchartbox}%
      }%
    \fi 
    \centerline{\box\flowchartbox}%
    \vspace{0pt minus .5pt}% fix for rounding errors in \resizebox
    \nointerlineskip
    \centerline{\box\captionbox}%
  \end{minipage}%
\end{figure}

\end{document}

Measuring positions

The second method uses package zref-abspage to measure the positions that are written to the .aux file first. In the second run, the correct positions are known and used.
Update: This example is not updated regarding the scaling behaviour.

\documentclass{article}

\usepackage[showframe,letterpaper, margin=0.5in, includefoot]{geometry} % Advanced page geometry configuation

\usepackage{fancyhdr} % Used for header and footer creation
\pagestyle{fancy}
\fancyhf{} % clear all fields
\lfoot{Lorem\\Ipsum}\cfoot{dolor sit\\amet \\ \thepage}\rfoot{Rev. \#\\ \today}

\usepackage{tikz} % Flowcharts

\renewcommand{\headrulewidth}{0.0pt} % removes line at top that comes w/ fancyhdr

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\usepackage{graphicx}
\usepackage{tikz}

\usetikzlibrary{shapes, arrows, positioning, calc, matrix}

% Define block styles
\tikzstyle{state}   = [ rounded rectangle,
                        draw,
                        text centered,
                        minimum height = 3em,
                        minimum width = 6em,
                        inner sep = 5pt
                        ]
\tikzstyle{test}    = [ diamond,
                        draw,
                        shape aspect = 2,
                        inner sep = 0pt,
                        text width = 7em,
                        text centered
                      ]
\tikzstyle{action}  = [ rectangle, draw,
                        text width = 8em,
                        inner sep = 5pt,
                        minimum height = 5em
                      ]
\tikzstyle{data}    = [ trapezium,
                        draw,
                        trapezium left angle = 60,
                        trapezium right angle = 120pt,
                        minimum height = 6em,
                        text width = 5em,
                        inner xsep = 0pt
                       ]
\tikzstyle{line}    = [ draw, -triangle 45 ]

\usepackage{zref-savepos}
\providecommand*{\zsaveposy}{\zsavepos}% support older zref-savepos

\newdimen\flowheight

\begin{document}

\begin{figure}
\vbox to \textheight{%
  \centering
  \makeatletter
  \zsaveposy{flow-beg}%
  \zref@refused{flow-beg}%
  \setlength{\flowheight}{-\dimexpr\zposy{flow-end}sp-\zposy{flow-beg}sp\relax}%
  \resizebox{\textwidth}{%
    \ifdim\flowheight>0pt \flowheight\else .75\textheight\fi
  }{%
    \input{flowchart}% 
  }\par
  \vss
  \nointerlineskip
  \zsaveposy{flow-end}%
  \caption{\textbf {My Stupid Flowchart}}%   
}
\end{figure}

\end{document}