How do I embed fonts in an existing PDF?
Besides Ghostscript, it is also possible to use Poppler and Cairo. There is a command pdftocairo from Poppler that converts PDF to PDF via pdftocairo -pdf input.pdf output.pdf. It also considers font substitutions set in a Fontconfig configuration file. This is very helpful if you do not have all fonts on your system that are referenced in a PDF file, but know which other font you have installed is a good-looking replacement. After processing, the substitution font is embedded.
I had this problem today with an existing PDF I uploaded to lulu.com to make a printed copy. It was rejected for not having all fonts embedded.
I found that if I opened it in Acrobat X and Saved out as postscript .ps file, then when I double clicked this .ps file in File Explorer, it opened in Acrobat X Distiller, and this automatically created a new PDF file with all fonts embedded!
Naturally this would mean you must have all the fonts needed on your computer. Otherwise a program like InFix can make font substitutions.
I had this problem on a Mac with a PDF I was submitting to IEEE. Using Adobe Reader and Preview, I was able to get around this. I think any pdf printer might work in place of Preview if you are on a PC.
Here are the steps I took. You can individually fix each figure, or fix the whole document.
Open at pdf file using Adobe Reader.
Right click on image, and click “Document Properties.”
Click “Fonts.” Check to see if the font isn’t embedded. Should say “Courier” or other font name.
If your pdf isn’t a standard page size, click on “Description” and look at the page size. Write this down. Ex. 19.4 x 5.22 in.
Open the pdf up in Preview. Go to File->Print. If using a pdf that isn’t a standard page size, click on Paper Size and choose custom. You will need to create a custom page size that is equal to the one you wrote down in step 4. Don’t forget to zero the margins to 0 for all sides. After doing that, you’ll need to set the scale of the print in the print dialog to 100%.
In the lower left of the print dialog (in Preview on a Mac), click “PDF” to print the PDF to a new PDF. Select the destination and print.
Open the new pdf up in Adobe Reader and verify that the fonts are now embedded.
I hope this helps.
This may not be the answer you are looking for (since you want to get your problems solved programmatically, not by an external tool).
But you can use Ghostscript commandline to embed missing fonts in retrospect to PDFs which have not embedded them:
gs \
-sFONTPATH=/path/to/fonts:/another/dir/with/more/fonts \
-o output-pdf-with-embedded-fonts.pdf \
-sDEVICE=pdfwrite \
-dPDFSETTINGS=/prepress \
input-pdf-where-some-fonts-are-not-embedded.pdf
One important thing is that the missing fonts are all available in one of the directories pointed to by the -sFontPath=... switch.