EPUB -> PDF: Image Rather Than Text

claytoncarney · 01-02-2013, 12:36 PM

I've only been using calibre a few hours, so please bear with me if my questions seem obvious...

Background: I have my technical library in PDF files. I use Foxit Reader to read, highlight, and annotate my books. In order to highlight, the PDF files must contain embedded text, as opposed to an image of text. Sometimes desired books are not available in PDF, only EPUB. I'm seeking to use calibre to make the necessary conversion.

As a start, I converted the calibre Quick Start Guide EPUB. After tweaking the conversion preferences, I got a functional PDF. I obviously have much to learn, but so far, so good.

However, when I convert a technical book EPUB with the same preferences, I encounter an odd problem. The resulting PDF appears to be mostly an image, rather than embedded text. Only certain types of headings or mono-spaced fonts are converted to text. The remainder of the content appears to convert to an image of text, rather than actual text.

I've looked at the Debug dump. The OEBPS HTML files in the input, parsed, structure, and processed directories all clearly have the content text intact. Yet, the converted PDF appears to be almost completely an image.

The only possible clue I see is that the technical book EPUB includes several OTF font files. The calibre Quick Start Guide EPUB does not. Outside of that, I'm lost as to why I get such drastically different results from the same conversion preferences.

Any suggestions are greatly appreciated...

kovidgoyal · 01-02-2013, 12:56 PM

THe problem is caused by the fonts, and it will be fixed in the next release.

kovidgoyal · 01-03-2013, 04:32 AM

Actually, it turns out that it cannot be fixed as yet, on windows. It will not happen if you convert on linux or OS X, but Qt on windows has no support for Postscript fonts (it uses GDI instead of DirectWrite). The only way to fix it would be to drop support for Windows versions earlier than Vista SP2, which is not something that is worth the tradeoff at this time.

So you will have to either replace the otf fonts with truetype version of run the conversion ona linux or os x system.

claytoncarney · 01-03-2013, 12:15 PM

Thank you for the excellent support!

Ran the conversion using calibre 0.9.12 on Fedora 17 with no problem.

Also used FreeFontConverter to convert otf to ttf, edited the various otf references, rezipped the epub, and ran the conversion using calibre 0.9.12 on Windows 7 with no problem.

calibre rocks! Many thanks for this great product...

01-02-2013, 12:36 PM	#1
claytoncarney Junior Member Posts: 4 Karma: 10 Join Date: Jan 2013 Device: none	EPUB -> PDF: Image Rather Than Text I've only been using calibre a few hours, so please bear with me if my questions seem obvious... Background: I have my technical library in PDF files. I use Foxit Reader to read, highlight, and annotate my books. In order to highlight, the PDF files must contain embedded text, as opposed to an image of text. Sometimes desired books are not available in PDF, only EPUB. I'm seeking to use calibre to make the necessary conversion. As a start, I converted the calibre Quick Start Guide EPUB. After tweaking the conversion preferences, I got a functional PDF. I obviously have much to learn, but so far, so good. However, when I convert a technical book EPUB with the same preferences, I encounter an odd problem. The resulting PDF appears to be mostly an image, rather than embedded text. Only certain types of headings or mono-spaced fonts are converted to text. The remainder of the content appears to convert to an image of text, rather than actual text. I've looked at the Debug dump. The OEBPS HTML files in the input, parsed, structure, and processed directories all clearly have the content text intact. Yet, the converted PDF appears to be almost completely an image. The only possible clue I see is that the technical book EPUB includes several OTF font files. The calibre Quick Start Guide EPUB does not. Outside of that, I'm lost as to why I get such drastically different results from the same conversion preferences. Any suggestions are greatly appreciated...

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01-02-2013, 12:56 PM	#2
kovidgoyal creator of calibre Posts: 43,843 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	THe problem is caused by the fonts, and it will be fixed in the next release.

01-03-2013, 04:32 AM	#3
kovidgoyal creator of calibre Posts: 43,843 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Actually, it turns out that it cannot be fixed as yet, on windows. It will not happen if you convert on linux or OS X, but Qt on windows has no support for Postscript fonts (it uses GDI instead of DirectWrite). The only way to fix it would be to drop support for Windows versions earlier than Vista SP2, which is not something that is worth the tradeoff at this time. So you will have to either replace the otf fonts with truetype version of run the conversion ona linux or os x system.

01-03-2013, 12:15 PM	#4
claytoncarney Junior Member Posts: 4 Karma: 10 Join Date: Jan 2013 Device: none	Thank you for the excellent support! Ran the conversion using calibre 0.9.12 on Fedora 17 with no problem. Also used FreeFontConverter to convert otf to ttf, edited the various otf references, rezipped the epub, and ran the conversion using calibre 0.9.12 on Windows 7 with no problem. calibre rocks! Many thanks for this great product...

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