More Margin Questions

[enuddleyarbl]

Originally Posted by bookman156

You mean your Kobo has an approximately 1em margin even when it's set at zero? Does that change if you set margin to 0.5em in the CSS or does it remain the same?

Well, this is interesting. I set up a fake book with margins all around of 0, 0.5em and 5.0em. In the Calibre Editor and Viewer, they all reflect their margin settings. On my Kobo, the margin I set on the device overrides the margin set in the book. IOW, they all look identical on the Kobo and reflect what I've set the Kobo to display. All of the below are screenshots instead of actual pictures of the Forma. But, that's exactly what shows on screen.

With margin set to 0:


With margin set to 0.5:


With margin set to 5.0em:


And, here's a link to one of the books:
https://drive.google.com/file/d/1NdG...ew?usp=sharing

[bookman156]

Well, this is interesting. I set up a fake book with margins all around of 0, 0.5em and 5.0em. In the Calibre Editor and Viewer, they all reflect their margin settings. On my Kobo, the margin I set on the device overrides the margin set in the book. IOW, they all look identical on the Kobo and reflect what I've set the Kobo to display.

Much as I suspected. Thanks.

[enuddleyarbl]

Originally Posted by bookman156

Much as I suspected. Thanks.

Of course, in Calibre's Viewer, the margins set in the book override those set in the viewer. So, the issue still remains.

EDIT: Also, I only tested using a kepub on the standard kepub viewer on the Forma. I have no idea how things behave with epubs or other viewers that might be on the device.

[bookman156]

Of course, in Calibre's Viewer, the margins set in the book override those set in the viewer. So, the issue still remains.

The issue is really whether setting a margin on body other than 0 prevents any reader from overriding it. It was stated that this is the case for Kobo, but you have shown that it is not.

EDIT: I only make epub3. I don't know much about kepub but apparently epub3 can only be read by the kepub reader on Kobo.

[DNSB]

Originally Posted by bookman156

EDIT: I only make epub3. I don't know much about kepub but apparently epub3 can only be read by the kepub reader on Kobo.

That is correct. The epub3 renderer on a Kobo ereader is selected by using the .kepub.epub file extension. The RMSDK renderer handles some epub3 features but is not a true epub3 renderer.

Kobo could use the file version to trigger selecting the renderer but that would also require handling an epub3 file with Adobe DRM.

[bookman156]

Kobo could use the file version to trigger selecting the renderer but that would also require handling an epub3 file with Adobe DRM.

Not quite sure what you're saying there. What happens to a non-DRM epub3 on a Kobo? Does it trigger the kepub renderer?

[DNSB]

Originally Posted by bookman156

Not quite sure what you're saying there. What happens to a non-DRM epub3 on a Kobo? Does it trigger the kepub renderer?

No. The file extension is the only selector in use. The issue is that you can receive an epub3 with Adobe encryption which the webkit based renderer would not be able to open so it is not as simple as checking the epub version in the .opf file to decide which renderer to use.

There are also differences in font handling, CSS support, etc. between the two renderers. This has led to near religious arguments over which is better though for the most part, most people would probably not notice all that much difference (IMNSHO).

[bookman156]

I see. So though Kobo supports epub3, it wouldn't be able to tell whether an epub3 with Adobe encryption was epub 2 or 3. But for an epub3 without any DRM no problem.

[j.p.s]

What happens when margin is not specified at all for body text?

[DNSB]

Originally Posted by bookman156

I see. So though Kobo supports epub3, it wouldn't be able to tell whether an epub3 with Adobe encryption was epub 2 or 3. But for an epub3 without any DRM no problem.

Not quite right. The .opf file is not encrypted so you can still check for the version="" to see if it was an epub2 or epub3. Then you would check for encryption.xml and rights.xml files in the META-INF directory and parse them to see if the book itself is encrypted (you need to parse the files since encryption.xml is also used for font obfuscation and I have had a couple of downloaded library books without DRM that had those files).

Basically, using the file extension to decide which renderer to use is simpler and allows you to force which renderer to use.

[enuddleyarbl]

Originally Posted by j.p.s

What happens when margin is not specified at all for body text?

I removed my @page and body classes entirely from the stylesheet (so no margins or anything else set to anything specific). AFAICS, it looks the same on my Forma as it did with the @page and body styles present. So, for kepubs on a Forma, it looks like the margin settings on the device override those set in the book. Heck, it looks like the Forma overrides everything I had in my body classes.

Also, with my previous testing, I had an html set of styles set in that stylesheet (it was set on the body styling):

https://www.mobileread.com/forums/sh...d.php?t=348891

With that present, the Calibre Viewer used the margins set in the book over the margins set for the Viewer. But, when I removed the html styles, the behavior became the same as for the Kobo: the Calibre Viewer used its margin settings instead of the books'.

[JSWolf]

Originally Posted by DNSB

That is correct. The epub3 renderer on a Kobo ereader is selected by using the .kepub.epub file extension. The RMSDK renderer handles some epub3 features but is not a true epub3 renderer.

Kobo could use the file version to trigger selecting the renderer but that would also require handling an epub3 file with Adobe DRM.

Kobo would need to install the latest RMSDK in order to handle ePub 3 with DRM properly.

[DNSB]

Originally Posted by bookman156

The issue is really whether setting a margin on body other than 0 prevents any reader from overriding it. It was stated that this is the case for Kobo, but you have shown that it is not.

EDIT: I only make epub3. I don't know much about kepub but apparently epub3 can only be read by the kepub reader on Kobo.

The issue with margins on a Kobo is that if you set a 2em left and right margins, your Kobo ereader using the RMSDK renderer can increase those margins but not reduce them.

[DNSB]

Originally Posted by JSWolf

Kobo would need to install the latest RMSDK in order to handle ePub 3 with DRM properly.

Depends on what epub3 features are used. Most of the ebooks and library ebooks I get these days are epub3. RMSDK disregards the accessibility bits and bobs and renders them quite happily despite them being DRMmed.

[JSWolf]

As was said by @DNSB, the margins for ePub are not overridden. You can only add to them. So if you have say a 1em L/R margin, that becomes your minimum margin. So please, leave the margins alone and set them to 0.