01-30-2018, 05:57 AM | #1 |
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Indesign to fixed layout epub very slow
Hello
I have a problem with a fixed layout epub that I've tried to solve for a long time to no avail, thought maybe asking for help here would be a good idea. I'm converting a ~600-page maths textbook to fxl epub. I have the design in Indesign, interactions work and all displays very nicely. However there's a problem when opening the epub in any tablet reader (I have an older iPad 2 and a Lenovo pad for testing). Each page takes a few seconds to load on tablets. The epub itself is very large - around 40MB, since all the formulas and math symbols are represented as png pictures and it's quite heavy on them. I have two main suspects - both stemming from Indesign:
Example page: https://pastebin.com/vGqVatD5 I'm using Indesign CC2017 and Sigil. Using Indesign is mandatory for this project, since it holds the design and re-doing the 600 page maths textbook and realigning all formulas etc. in some other program is just not worth the time. Sigil was for cleanup, it actually reduced the file size Can anyone point me to some direction - I might not have thought about everything yet which might make the reading experience slow. |
01-30-2018, 05:23 PM | #2 |
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Here is one suggestion. Forget using PNG for your math formulas. You can try SVG. The link below is a site that lets you create math formulas and save them as SVG.
https://www.codecogs.com/latex/eqneditor.php |
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01-31-2018, 12:27 AM | #3 |
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Thank you for the suggestion. The thing is, that the PNGs get created automatically by exporting from Indesign - I already have all of the formulas and special cases as *.eps files. It's a conversion of already existing printed textbook, which was originally designed in Indesign - there are around 8000 of them, so it doesn't seem too reasonable to replace them with svg-s manually.
Is there a significant performance boost by using svg instead of png? If I have to do it, I'd really rather know that it would help. I guess another thing that could be done would be to re-do everything in Sigil, just design it in Indesign, now that I have all formatting design questions solved. But again, I'd really rather do it only if I know that I cannot use Indesign's exported epub somehow, this issue seems kind of silly. |
01-31-2018, 09:42 AM | #4 |
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There can be a significant increase in clarity with SVG. I have no idea if SVG will be faster or not. But, SVG scales much better to any resolution screen.
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01-31-2018, 08:13 PM | #5 |
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02-01-2018, 06:44 AM | #6 |
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02-01-2018, 07:41 AM | #7 |
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Given that the OP is not using MathML, Jon, and presumably has no intention of re-writing his book to use it (a significant task, given that he states that there are 8000 equations in the book), it's rather a moot point which renderers do or don't support it. It's not an answer to the OP's problem.
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02-01-2018, 10:33 AM | #8 |
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If your "chapter" xhtml files are large and hold many many images, consider splitting them into separate files for each section. Assuming numeric section numbering, having and using a separate file xhtml file for each major section within a chapter, should greatly speed loading on all devices.
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02-01-2018, 10:38 AM | #9 | |
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Quote:
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02-01-2018, 10:41 AM | #10 |
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I missed that! Wow 93,000 line CSS file would definitely kill loading times. Perhaps he could make a copy of the file for each xhtml file and then link it to just one xhtml file and then strip out any and all CSS rules that are not used in that particular xhtml file?
What on earth would need that many rules? |
02-01-2018, 10:50 AM | #11 |
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Remember, InDesign makes a rather sloppy CSS. I've seen this in many ID created ePub. And I would think with something this complex, it owuld make even more of a mess.
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02-01-2018, 01:36 PM | #12 |
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Thank you for your ideas so far.
I tried and researched a little bit more - splitting up the css surprisingly did not help. It seems it's the combination of both every element (and word) being absolutely positioned, scaling and css issues - I redid manually a few first pages in Sigil to take control over the source code and that one loads nicely and fast. Which is a real shame for Indesign. I also looked into MathML, for performance and size issues would like to get rid of as much images and redundant css as possible - I guess there is no fast way of doing it. The fastest way to get nearly anything acceptable seems to be lots of regex and still get MathML going - most of the symbols are actually not that complicated, having {a over b} and later replacing them all with mathml syntax will indeed mean lot's of work but also finally a solution. As for splitting up the "chapters" - if it's fixed layout, each page is a separate xhtml anyway, no? |
02-01-2018, 02:40 PM | #13 |
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Yes, a page per file. That said, why does InDesign not simply position an entire text line or text box instead of positioning every single word?
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02-01-2018, 03:26 PM | #14 |
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With fixed layout, what happens if someone wants the text to be fairly large?
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02-01-2018, 03:44 PM | #15 |
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Fixed layout means exactly that. It’s like a PDF: fixed content on a page. You can zoom in on it, but it doesn’t reflow.
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