Don't want to release your source code just because you need to add watermarks to your file(s). Python Watermark Allows you to easily add watermarks to PDF, JPG & PNG files with no restrictive licensing
Installing the latest PyPI release (recommended)
python3 -m pip install -U pythonwatermark
This will use a pre-built wheel package, the easiest way of installing pythonwatermark.
pythonwatermark uses two awesome open source python packages to work it's magic they are...
Pillow - https://github.com/python-pillow/Pillow
Like PIL, Pillow is licensed under the open source HPND License
Pypdfium2 - https://github.com/pypdfium2-team/pypdfium2
PDFium and pypdfium2 are available by the terms and conditions of either Apache-2.0 or BSD-3-Clause, at your choice.
These are both fantastic packages and are liberally licensed meaning unlike with other options you don't need to release your source code to the public.
Import watermark utils
from pythonwatermark import watermarkutils
Add watermark to file
watermarkutils.put_watermark(inputfile, outputfile, watermark, x=0, y=0, transparency=100, width=None, height=None)
inputfile - path as string to PDF, JPG or PNG you wish to add watermark too
outputfile - path as string to where you want output to be saved with either PDF, JPG or PNG file extension.
watermark - path as string to PDF, JPG or PNG file you are using as your watermark
inputfile - can be PDF, JPG or PNG.
outputfile - can be PDF, JPG or PNG if the input file is not a PDF. If the input file is a PDF the output file will either be a PDF or you can pass a folder string and the output will be an image per page in JPG format.
watermark - can be PDF, JPG or PNG. Only PNG supports transparency otherwise the background will be included. If you select a multipage PDF as the watermark it will only take the first page as the image/text to be added as a watermark
x - start point along the x axis for the watermark to be inserted, this can be in PX or "left", "centre" or "right" (if not included x defaults to 0)
y - start point along the y axis for the watermark to be inserted, this can be in PX or "top", "middle" or "bottom" (if not included y defaults to 0)
transparency - the transparency/opacity of the inserted watermark in %. 100% is fully visible 1% is barely visible
width/height - Use one or the other to resize the width/height of the watermark keeping the aspect ratio intact
Use getpxsize to return the size in pixels of a file (input file or watermark for custom positioning)
w, h = watermarkutils.getpxsize(inputfile)
If you are resizing a watermark you can also add either the width/height you are resizing to for more accurate placement on the input file
w2, h2 = watermarkutils.getpxsize(watermark, width=300)
w3, h3 = watermarkutils.getpxsize(watermark, height=300)
You can use this to work out watermark placement on your input file
w, h = getpxsize(inputfile)
w2, h2 = getpxsize(watermark)
x = int((w / 2) - (w2 / 2))
y = int((h / 2) - (h2 / 2))
This would provide the X & Y to have the watermark positioned in the centre/middle of the page (though we can also achieve this by passing x="centre" & y="middle")