The reader of my university lecture regularly posts lecture notes online. The pdf contains handwritten mathematical theorems including the proofs. Everything is written on a completely white background.

I want to create a new printable file containing the theorems and comments only (no proofs) as exam preparation

Is there an easy tool able to accomplish this on a Mac running High Sierra? It may be a bit tricky to get the breaks in pages right. The workflow would ideally look like this:

Use rectangular selection tool to highlight proof. Hit some key to delete selected area/fill the rectangle white. Select everything below the proof and move it upwards until no whitespace is left.


Maybe think from the opposite side...

  • Open your PDF
  • Select an area you want to keep.
  • Cmd ⌘ C to copy, then Cmd ⌘ N which will open a new document with the clipboard contents.
  • Repeat for each section you want to keep.
  • Save each of your new sections as separate files. Use the default name, which will number in save order, these will be ephemeral.
  • Close everything.
  • Select all your newly-saved files in Finder & Open
  • They will all open in one window, in file order.
  • You can then Print the whole lot as a single document - to PDF.

Requires Preview prefs > General > Open groups of files in the same window

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  • Saving works, but when selecting multiple files and opening them will lead to multiple preview windows. How do I merge these files? – user7802048 Dec 27 '17 at 16:16
  • Preview prefs > General > Open groups of files in same window – Tetsujin Dec 27 '17 at 16:22
  • Strange. This is already selected. You just selected all the files in Finder - Open With - Preview? – user7802048 Dec 27 '17 at 16:23
  • Yup, or for me as Preview is default, just select, cmd/O – Tetsujin Dec 27 '17 at 16:25
  • Still not doing it for me. Maybe I'm selecting wrong or something. Even selecting Open all files in one window does not work. – user7802048 Dec 27 '17 at 16:27

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