commit 9be7d62d592cd500234486360b61b723a514df8e
Author: Louis Vallat <louis@louis-vallat.xyz>
Date:   Wed Dec 15 18:56:10 2021 +0100

    Initial commit
    
    Signed-off-by: Louis Vallat <louis@louis-vallat.xyz>

diff --git a/README.md b/README.md
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+++ b/README.md
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+# Watermark
+
+> Add watermarks on your PDFs.
+
+## How to use
+
+```bash
+./watermark.sh <PDF FILE>
+```
+
+You can watermark multiple PDFs by using the `find` command, such as :
+
+```bash
+find ./folder -name "*.pdf" -exec ./watermark.sh {} \;
+```
+
+The watermarked PDF is named <PDF FILE>-out.pdf. The original one is not deleted.
+
+## How it works
+
+First it creates the watermark in a specific file, then it exports the PDF in
+multiple PNGs, and watermark each extracted page, still in the PNG format so it
+cannot be then edited or modified (easily) using some PDF editing software.
+
+The script is pretty short and straightforward to read, you can adapt without
+much difficulties I believe.
+
+## Additional notes
+
+This was part of a personnal project that wasn't supposed to be made public, so
+excuse the lack of comments and code dirtiness.
+
diff --git a/watermark.sh b/watermark.sh
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+#!/bin/bash
+
+WATERMARK_TEXT="VOTRE TEXTE À WATERMARKER"
+COLOR="red"
+INPUT_PDF="$1"
+OUTPUT_PNGs="./pdf"
+WATERMARK_SIZE=50
+WATERMARK_PNG_SIZE="800x300"
+
+convert -size ${WATERMARK_PNG_SIZE} xc:white -font Arial -pointsize ${WATERMARK_SIZE} \
+          -gravity NorthWest -draw "fill ${COLOR} text 70,15  '${WATERMARK_TEXT}'" \
+          -gravity SouthEast -draw "fill ${COLOR} text 70,150  '${WATERMARK_TEXT}'" \
+          stamp.png
+
+pdftoppm ${INPUT_PDF} ${OUTPUT_PNGs} -png
+
+for pic in *.png; do
+    if [ ${pic} != "stamp.png" ]; then
+        composite -dissolve 25% -tile stamp.png ${pic} ${pic//.png}-marked.png
+    fi
+done
+
+convert *-marked.png ${INPUT_PDF}-out.pdf
+rm *.png
+