Engineering books are very expensive in my country. I want to give calculus a spin. Spivak is a hundred dollars.
Check with a lady named "Anna" on the interwebs for ebook versions of those books which you need but cannot afford.
Show HN: Free textbook on engineering thermodynamics
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Re: Show HN: Free textbook on engineering thermodynamics
#52Earlier quoted context omitted.
Probably the main thing you could look at is what pixel density you want in your images. For example, there's a 1 megabyte image of a tanker trailer that is displayed at about 1.5 x 3 inches, you could get rid of 3/4 of those pixels (going from ~400 ppi to ~200 ppi) and not really change the quality of the image for a casual reader.
that’s a really good place to start, thank you!
One week later, a follow-up. I went through the largest JPG files and was able to shave 7 MB off the final PDF file size, with no noticeable drop in quality, as far as I can tell:
https://framagit.org/olivier/thermodynamique/-/commit/063038...
As for the PNG files, I gave up after spending a whole day on them. I was able to compress them losslessly to save 6 MB, but this did not carry over into the PDF, where they are not embedded but re-encoded. The best way to save space here would be to switch to SVG, but this is too much work and last time I tried 12 years ago it did not work well. Alternatively, removing transparency would help (and anyway the source SVG is given for each file). But that’s not very future-proof and somewhere I know there’s a teacher who just is going to right-click-save a diagram and will get a nice crisp transparent-background PNG they can instantly reuse. Verdict: at this point, I am calling it good enough. :-)
Re: Show HN: Free textbook on engineering thermodynamics
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