compress-pdf (90% compression with simple commands)

README.md

I was looking to compress PDF files (typically poster for event and such are massive)

• online tools is not a solution for sensitive data, process is tiedous to check compression rate ;
• other tools require Python (cf. minimalpdfcompress, pdfc) ; but Local compress of PDF with ~90% efficiency (way better than online tool) using only CLI tool
• in-browser solution compress so much that content isn't readable (cf. CompressPDF) ;
• DjVu format is super efficient as it's designed to store document
• Currently no OCR, if you need it check pdf2djvu-ocr

Requirement

sudo apt-get install \
    djvulibre-bin \
    ghostscript \
    pdf2djvu

Usage

compress-pdf input-big.pdf [compressed.pdf]

compress-pdf.bash

compress_pdf() {
    local inputFile="$1"
    local outputFile="$2"
    local djvuFile

    if [ -z "$inputFile" ]; then
        echo "Usage: compress_pdf inputFile [outputFile]"
        return 1
    fi

    if [ -z "$outputFile" ]; then
        outputFile="${inputFile%.pdf}.compressed.pdf"
    fi
    djvuFile="${inputFile%.pdf}.djvu"

    if pdf2djvu --dpi=300 --output="$djvuFile" "$inputFile"; then
        echo "✅ Converted to Djvu"
    else
        echo "❌ Failed to convert to Djvu"
        return 1
    fi

    if ddjvu -format=pdf -quality=85 "$djvuFile" "$outputFile"; then
        echo "✅ Compressed back to PDF"
    else
        echo "❌ Failed to compress to PDF"
        return 1
    fi
}

compress-pdf.fish

function compress-pdf \
    --description 'Compress a PDF file by converting it to Djvu and back to PDF. outputFile name is optional' \
    --argument-names inputFile \
    --argument-names outputFile \
    --argument-names dpi \
    --argument-names quality

    if not test -f "$inputFile"
        echo "❌ Input file not found: $inputFile"
        return 1
    end

    set djvuFile (string replace '.pdf' '.djvu' $inputFile)    
    set --query dpi[1]; or set dpi 300 # smaller dpi means smaller file size but lower quality
    pdf2djvu --dpi=$dpi --output="$djvuFile" "$inputFile" --verbose
    if test $status -eq 0
        echo "✅ Converted to Djvu"
    else
        echo "❌ Failed to convert to Djvu"
        return 1
    end

    set --query outputFile[1]; or set outputFile (string replace '.pdf' '.compressed.pdf' $inputFile)
    set --query quality[1]; or set quality 75 # smaller quality means smaller file size but lower quality
    ddjvu -verbose -format=pdf -quality=$quality "$djvuFile" "$outputFile"
    if test $status -eq 0
        echo "✅ Compressed back to PDF"
    else
        echo "❌ Failed to compress to PDF"
        return 1
    end
end