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# Home / Question about zoom in ebook UI

Gunivortus

Sorry to border, the search option here did not provide me an answer.

After installing Sumatra PDF at my Samsung Galaxy W703 tablet, I want to use it as my eReader program. But the option + to zoom in, to get the font bigger, does not work, neither in laptop mode (with the external keyboard), nor in tablet mode with the virtual keyboard.
How can in zoom in and zoom out now? With bad eyes, I really need that option.

kjk

Currently the ebook UI doesn’t have zoom.

You can switch ebook UI to traditional UI by setting EbookUI [ UseFixedPageUI = true ] in Settings -> Advanced Settings.. and then zoom will be available.

Gunivortus

Thank you for your answer.
That did work.
However, zooming in till I get it convenient readable for me, I do not get it all fitting at the screen anymore. Is there a setting which keeps the text at the screen without scrolling horizontally, despite the bigger font size? So, just less text at a page.

kjk

I guess there is no such option but I don’t really understand the issue.

A window size and font size determine how much text can be shown.

If you can’t change the font size, then make the window bigger.

If the window takes full space and it’s still not enough, then it’s physically impossible to show more text with changing the font size.

Gunivortus

Concerning the issue…
Just to compare… If ADE is used as eReader program, then zooming in increases the font size but it does not affect the page width. If in a smaller size 20 words were on one line, then after zooming, 14 words are on that line, the page width is kept. That also is how it is handled at an eReader. It means that the amount of pages of an eBook increases this way.

In the classic view of Sumatra I can resize the font, but it also affects the page width … the same 20 words are kept on the one line, and to see them all I have to scroll horizontally.

But if this fixed page width with less words on a line is not possible in Sumatra, I assume, I have to use ADE or the Calibre Reader, although I would prefer Sumatra because of its good PDF handling which isn’t good in ADE.

SumatraPeter

Just to compare… If ADE is used as eReader program, then zooming in increases the font size but it does not affect the page width. If in a smaller size 20 words were on one line, then after zooming, 14 words are on that line, the page width is kept. That also is how it is handled at an eReader. It means that the amount of pages of an eBook increases this way.

What you want is for the text to re-flow on zooming in. Different document readers/editors behave differently in this regard. Take MS Word for example - if you select all the text (Ctrl+A) and increase the font size (Ctrl+]), the page width remains unaffected but naturally less text fits on each line and thus the text re-flows. However if you simply press Ctrl and scroll the mousewheel up, the document view is zoomed, thus increasing the page width such that eventually you’ll see a horizontal scrollbar. Sumatra behaves the same way while zooming, especially since it doesn’t offer any means to change the font size of displayed text through the UI and the only way to do it is for EbookUI via Advanced Options:

[
FontName = Georgia
FontSize = 12.5
]
Gunivortus

Thank you for clarifying. Yes, re-flow was the term I did not find.
I have to try it out some more with EPUB and PDF using Fontsize = 16.
At first glace the re-flow seems to work with EPUB, the page width is kept, no horizontal scrolling.
But with PDF it doesn’t yet, but I 've to try it out some more.
Thanks again.

SumatraPeter

That’s because PDFs are displayed using FixedPageUI, which doesn’t have any font related options.

Gunivortus

Thanks.
Indeed, I see in the Advanced settings the options for EbookUI and ChmUI to set UseFixPageUI to false but not for PDF.
Pity.

kjk

Indeed, I see in the Advanced settings the options for EbookUI and ChmUI to set UseFixPageUI to false but not for PDF.

That is the nature of the PDF. The format was designed for printing so it relies on pixel-perfect reproduction of the content.

Doing things like changing layout/reflowing of the PDF is impossible in general case and very hard to do even when PDF is mostly text, which is why Sumatra doesn’t do it.

Gunivortus

OK, I can understand that reason. But then, the Calibre e-book reader can read PDFs with reflow when the font size is increased. For me, being visually handicapped, is that really practical.
Would like if Sumatra would get that option too.

HerbM

thanks that (UseFixedPageUI = true) worked.

Is there a way to reset/reload the document to display in the new form without explicitly closing and re-opening it?

Re-opening (separately) isn’t awful, but it would be nice to just refresh options or something.

GitHubRulesOK

With latest versions 3.2 and more recent you don’t need to edit FixedUI=true

Debug > Toggle ebook UI [checked] is the same as EbooukUI use fixed = true so you can open txt files etc.
Each time you Toggle it you need to also press R manually it would be nice if it was automatic.

For whatever reason i.e. using 3.1.2 changing manually then Press R for Refresh / Reload

Using R in recent versions has a known small bug that it may slightly shift the view port in some documents