Read barcode from PDF document

  • Hi, I have a question. Is there a way to convert pdf to jpg?
    I need to read the images from a pdf document. I am using QZXing to read barcodes. Barcodes must be in image format (jpg, png ...)

    Thanks for the help.

  • Qt Champions 2017

    You can use command lines tools to do it.

  • Ok. But I want do this in my application. Your solution working on other application.

  • Hi! ImageMagick can convert PDF to JPEG. If you don't want to use it as a command-line tool, you can also use it as a library.

  • Qt Champions 2017

    There is no good way to do this directly in Qt.
    You might be able to display a pdf and screen grab it but calling external cmdline program with
    QProcess will work far better.
    Or as wieland suggest using ImageMagick library.

    There is also this
    Says "QPdfDocument can render a PDF page to a QImage"
    But i have not tried it.

  • @mrjj said in Read barcode from PDF document:

    There is also this
    Says "QPdfDocument can render a PDF page to a QImage"

    Awesome! \o/

  • Ok, i downloaded ImageMagick-i686-pc-mingw32.tar.gz.
    And now as I type

    convert f.pdf d.jpg

    f.pdf is in the same directory as convert.exe

    I get the message:

    convert.exe: UnableToOpenConfigureFile `delegates.xml' @ warning/configure.c/GetConfigureOptions/616.
    convert.exe: `%s' (%d) "gs" -q -dQUIET -dSAFER -dBATCH -dNOPAUSE -dNOPROMPT -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=2 "-sDEVICE=pngalpha" -dTextAlphaBits=4 -dGraphicsAlphaBits=4 "-r72x72"  "-sOutputFile=C:/Users/ADMINI~1/AppData/Local/Temp/magick-21380jSugM5nyzl-T-1" "-fC:/Users/ADMINI~1/AppData/Local/Temp/magick-21380wnE6NbHjVB6v" "-fC:/Users/ADMINI~1/AppData/Local/Temp/magick-21380qrAlRMgDXCHT" @ error/utility.c/SystemCommand/2033.
    convert.exe: PostscriptDelegateFailed `f.pdf': No such file or directory @ error/pdf.c/ReadPDFImage/682.
    convert.exe: NoImagesDefined `d.jpg' @ error/convert.c/ConvertImageCommand/3106.

  • When working with PostScript files, ImageMagick relies on another program, "Ghostscript" for the reading and conversion of PostScript and PDF files into a image format it can use. That is to read such documents, Ghostscript needs to be installed on your computer. Its latest version can be downloaded at github.

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