64 Zeilen
2,6 KiB
Markdown
64 Zeilen
2,6 KiB
Markdown
# pdf-sign
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## What
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A tool to sign PDF files, with Linux support.
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We are here referring to the visible, non-cryptographic squiggles.
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## How
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First, create one or several signatures in the form of small PDF files with transparent backgrounds.
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The recommended way is:
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* Use the included `pdf-create-empty` tool to create an empty, transparent PDF file.
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If 3×2 inch suits you, you can use [empty-3inx2in.pdf](empty-3inx2in.pdf) directly.
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* Use an application of your choice to sign it.
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You can for example use Okular's Freehand Line, or transfer it to your smartphone and use Adobe Acrobat Reader.
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Keep in mind that it's the center of this mini-page that will be used for positioning the signature.
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* Put the signed file in `~/.pdf_signatures/`.
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You can now use the `pdf-sign` tool interactively (or non-interactively) to sign PDF files.
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The GUI is self documented and allows both keyboard-only and pointer-only operation.
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Run `pdf-sign -h` or `pdf-create-empty -h` for details.
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**Installation**
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* Install dependencies
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* `python3.7` or later
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* Python module `tkinter` (only needed for interactive use)
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* `gs` (Ghostscript)
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* `pdftk`
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* `pdfinfo`
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* Copy one or both tools to a directory in your `$PATH`.
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**Installation on Debian**
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```sh
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apt-get update
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apt-get install -y coreutils git python3 python3-tk ghostscript pdftk poppler-utils
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git clone https://github.com/svenssonaxel/pdf-sign.git
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cd pdf-sign
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cp pdf-sign pdf-create-empty /usr/local/bin/
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```
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## Why
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There appears to be a lack of applications that run on Linux and allow for attaching free-hand signatures to PDF files in a good way.
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(Non-)alternatives include:
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* **Xournal and Xournal++:**
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Allows free-hand annotations, but not saving those for later use.
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Allows inserting images and .pdf files but will rasterize them rather than retain the vector graphics, resulting in lower quality.
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* **LibreOffice Draw:**
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Allows inserting images and .pdf files but will rasterize them rather than retain the vector graphics, resulting in lower quality.
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* **Okular:**
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Allows free-hand annotations, but not saving those for later use.
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Allows inserting custom saved stamps, but will rasterize them rather than retain the vector graphics, resulting in lower quality.
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(Older versions of Okular might save the stamps in a way that isn't visible in other PDF readers.)
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* **Evince:**
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Allows certain kinds of annotations, but nothing that can look like a free-hand signature.
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* **pdftk**, **ghostscript**, and other command-line tools:
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Allows superimposing .pdf files, but not interactively selecting where.
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