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Old 03-25-2011, 03:49 PM   #1
Sciamano
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Math formulas conversion help

Hi!
I'm trying to convert a PDF about Fermat's last theorem ("no three positive integers a, b, and c can satisfy the equation a^n + b^n = c^n for any integer value of n greater than two")

The problem is that the MOBI converted file loses most of the mathematical format. All exponents will become "normal" numbers and letters.
For example, in the converted file the above equation gets written as:

an + bn = cn

You can imagine it's impossible to read a mathematical text where the mathematical parts are not correctly formatted.

Any ideas?

Thanks
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Old 03-25-2011, 04:01 PM   #2
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The problem is that you are trying to convert a PDF. There is no way to get mathematical formulas from a PDF into another format. If you have the document in some other format I would recommend you use that.
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Old 03-25-2011, 04:03 PM   #3
Sciamano
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Unfortunately I only have a PDF.
So there is no solution at all?

(Thanks for the great software, by the way, Kovid!)
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Old 03-25-2011, 04:05 PM   #4
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You're welcome and no I know of no way to convert math formulae in a PDF. You can try various PDF cropping/resizing, PDF to image tools that might make your original PDF readable on the Kindle, but converting is not likely to happen.
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Old 03-25-2011, 04:17 PM   #5
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Marcel Weiher's TextLightning.app will attempt to convert positional information in a .pdf into text formatting and write out an .rtf --- it works surprisingly well, but not perfectly due to the difficulty of the task.

William
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Old 03-25-2011, 04:23 PM   #6
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Quote:
Originally Posted by WillAdams View Post
Marcel Weiher's TextLightning.app will attempt to convert positional information in a .pdf into text formatting and write out an .rtf --- it works surprisingly well, but not perfectly due to the difficulty of the task.

William
You do realize that Dr. Knuth wrote TEX (and MetaFont) because he was tired of his Math textbooks being mangled ?
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Old 03-25-2011, 05:42 PM   #7
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Thanks William, I'll try to convert to rtf with that app you talked about. Maybe it works.
I'll let you know.
Thanks everyone.

[edit]
Scratch that... just found out it's for Mac. I have no access to any Mac unfortunately.
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Old 03-31-2011, 08:16 AM   #8
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theducks, yes, I know about TeX, but Dr. Knuth wasn't working from .pdf originals, so I don't see why mentioning it here now is useful. FWIW, I have one of his (physical) reward checks and have published papers in TUGboat and edited the 2003 proceedings issue.

If the OP had access to the original source instead of the .pdf, this discussion would be different.

Sciamano, I believe Marcel has ported TextLightning to Windows and Linux using GNUstep --- you should contact him to see.

William
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Old 03-31-2011, 10:43 AM   #9
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Thanks Will. I tried googling for the windows version but couldn't find anything.
I've contacted Marcel, will let you know what he says.
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Old 04-01-2011, 05:34 PM   #10
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Question: Is there an app that can convert the formulas into embedded images and the whole document- into a supported format so that we can easily turn it into mobi with the Calibre?

Last edited by Kindle3fan; 04-01-2011 at 05:46 PM.
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Old 06-22-2011, 06:33 AM   #11
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I just got my Kindle last week and reading mathematic and lecture PDFs from university on it was the main reason for buying it. Although I'm okay with how it works (though there could be more options to pan, zoom and navigate, especially if a drawing is divided across the 3 zoom areas you get in landscape mode), I also tried to convert a few of those PDFs with Calibre to .mobi out of curiosity.

It's not only math formulas but also drawings that get misconverted. My idea is to improve heuristics to optionally detect drawings and render them to images instead and do the same for any formulas. Detecting formulas in LaTeX-generated PDFs could work quite well based on a recognition of the embedded fonts being used (simply by their embedded name?). Drawings could be detected by image recognition (render PDF page or paragraphs from it to image, run detection algorithm on that image to tell drawings/images from text and then decide how to convert it). It would of course be very slow but since you would convert a book only once, that should be okay. I'm sure a detection algorithm for text vs. graphics already exists in many implementations (OCR or OpenCV).

I'm not sure if anyone attempted to implement a detection/heuristic like that already. If I had some more spare time at the moment I would take a look at it; unfortunately I'm currently too busy, so I don't think I may come up with improvements any time soon. If anyone started/starts doing something like that, I'd be glad to know about it (maybe drop me a PM).

Last edited by EnQ; 06-22-2011 at 06:38 AM.
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