For a deck of lecture slides, I have extracted several vector illustrations from a PDF-file. I did this by highlighting the relevant area in Preview.app, copying, and opening a new file from the clipboard.
The figures look just fine, even though I noticed that the files are a little large. When I open them in Illustrator, I can see what's described in the screenshot – that all of the page content is still there, it's just hidden because it lies outside the crop area.
Now I could simply remove everything except the relevant figures in Illustrator, but I would much rather automate the process, since I have a large number of figures.
How can I automate this process such that everything outside the crop area is discarded and everything inside it is preserved as a vector image?
