Scale PDF page size _without_ adding white background

Question

I have a PDF containing an A5 page. For reasons, I want to "rescale" that page to be A4-sized - but not by adding margin/padding; I want the actual content scaled. i.e. the opposite of what this question asks for. I'm on a Windows 10 machine. How can I achieve this?

Note: The scaling must not involve rasterization, or any other degradation of quality.

Answer 1

_{(Answer due to @johnwhitington)}

Use a PDF command-line manipulation tool which supports such (lossess) scaling. One such tool is cpdf, short for "Coherent PDF".

1. Get the binary distribution from community.coherentpdf.com, or from the GitHub repo releases section. You can also get the source and build if you like.

2. In the ZIP archive, select the directory relevant to your platform, and decompress the binary any there into anyway on your path.

3. Assuming your input file is original.pdf and you want to create scaled.pdf , write:

   cpdf -scale-to-fit a4portrait original.pdf -o scaled.pdf
   

_{Note that if your PDF contains some rasterized images (such as PNG or JPEG) - its resolution on the scaled page will be lower: not because of any degradation by the scaling tool, but because the same number of pixels take up more space. That may appear less pleasing to the viewer.}