Combine multiple variable PDFs onto one page

Question

I have n PDFs in a folder. Each PDF contains only one small figure. I want to combine all of these onto one page, one on top of the other. I want to be able to specify just the directory that the PDFs are in and let LaTeX assemble them. It would be even better if I could call this from the command line so I didn't have to open my editor. My situation is like this one (at least the asker's pseudo code is exactly what I had in mind) but I can't understand the answer enough to make it work for combined PDFs.

If it makes it any easier, I could pass in the exact PDF file paths as arguments instead of just the directory. Both approaches are fine with me.

Thanks.

Answer 1

A batch solution save this .bat file in the same directory

@echo off 
setlocal EnableDelayedExpansion

(
echo \documentclass{article}
echo \usepackage{graphicx}
echo \begin{document} 
)> combine.tex
for /r %%a in (*.pdf) do (
set mtfile=%%a
set mtfile=!mtfile:%~dp0=!
set mtfile=!mtfile:\=/!
set mtfile="!mtfile:.=".!
echo \includegraphics{!mtfile!}>> combine.tex
echo.>> combine.tex
)
echo \end{document}>> combine.tex

rem could need to renove rem from next line and edit it to point pdflatex directory
rem set path=C:\programm...\miktex\bin;%path%
pdflatex combine.tex

by runing this file you will creat the combine.tex and compile it.

Answer 2

Inspired by touhami's brilliantly simple approach, I used the same technique but with Python.

import os, fnmatch, subprocess, getopt, sys

def combinePdfs(inputPdfsDir, outputFileName):
    removeOldCombinedFigure(inputPdfsDir + outputFileName + '.pdf')
    latexText = buildLatexText(inputPdfsDir)
    tempFilePath = inputPdfsDir + outputFileName + '.tex'
    saveTexFile(tempFilePath, latexText)
    callPdfLatex(tempFilePath)
    deleteGenereatedFiles(inputPdfsDir + outputFileName)

def removeOldCombinedFigure(oldCombinedPath):
    try:
        os.remove(oldCombinedPath)
    except OSError:
        pass

def buildLatexText(inputPdfsDir):
    graphics = fnmatch.filter(os.listdir(inputPdfsDir), "*.pdf")
    graphicHeight = 1.0 / len(graphics)
    latexText = """
    \documentclass{article}
    \usepackage{graphicx}
    \usepackage[margin=0.0in]{geometry}
    \\begin{document}
    \\begin{figure}
    \\centering"""
    for g in graphics:
        latexText += "\n\includegraphics[height="
        latexText += str(graphicHeight)
        latexText += "\\textheight,width=\\textwidth,keepaspectratio]{"
        latexText += g
        latexText += "}"
    latexText += "\n\end{figure}"
    latexText += "\n\end{document}"
    return latexText

def saveTexFile(texFilePath, latexText):
    tempFile = file(texFilePath, 'w')
    tempFile.write(latexText)
    tempFile.close()

def callPdfLatex(tempFilePath):
    inputPdfsDir = os.path.dirname(tempFilePath)
    windowsTempFilePath = tempFilePath.replace("/", "\\")
    outDirCommand = "-output-directory=" + inputPdfsDir
    args = ["C:\\Program Files (x86)\\MiKTeX\\miktex\\bin\\pdflatex.exe", outDirCommand, windowsTempFilePath]
    subprocess.call(args, shell = True)

def deleteGenereatedFiles(generatedFileNameNoExt):
    os.remove(generatedFileNameNoExt + '.aux')
    os.remove(generatedFileNameNoExt + '.log')
    os.remove(generatedFileNameNoExt + '.tex')

def usage():
    print('combine_pdfs.py -i C:\\dir_with_pdfs -o combinedPdf')

def main(argv):
    opts, args = getopt.getopt(argv, "h:i:o:")
    inputDir = None
    outputFile = None
    for opt, arg in opts:
        print opt
        if opt in ("-h", "--help"):
            usage()
            sys.exit(2)
        elif opt in ("-i", "--input_dir"):
            inputDir = arg
            if not inputDir.endswith('\\'):
                inputDir += '\\'
        elif opt in ("-o", "--output_file"):
            outputFile = arg
        else:
            usage()
            sys.exit(2)

    combinePdfs(inputDir, outputFile)

if __name__ == "__main__":
    argv = sys.argv[1:]
    main(argv)

Call from the command line like this:

python .\combine_pdfs.py -i C:\Users\yourname\Desktop\dir_with_pdfs -o combined