Question about validation and items referenced in css

[ldolse]

I just saw this thread about a particular epub crashing Nooks:
https://www.mobileread.com/forums/showthread.php?t=97542

And just for the hell of it decided to check what Sigil's epub validation said about the matter.

The only error was an issue with the SVG definition, easily enough fixed.

There were thee warnings about manifested but unreachable items though - the creator of the epub embedded his fonts and a background gif, all defined in the css, the items looked like this:

@font-face {
  font-family: "Goudy";
  src : url('../Fonts/OFLGoudyStM.otf')
}

@font-face {
  font-family: "Goudy Italic";
  src : url('../Fonts/OFLGoudyStM-Italic.otf')
}

#content h3 {
	text-transform: uppercase;
	text-align: center;
	margin: 1.5em 0 1.5em 0;
	font-size: 1.8em;
	line-height: 1.5em;
	letter-spacing: .1em;
	padding-bottom: 0.75em; /* space between text and image */
	background: url('../Images/underline.gif') no-repeat bottom center;	
}

So they are all technically 'reachable' at least from ADE's and QTWebkit's perspective - i.e. they were rendered. I was able to remove the two warnings for the fonts by changing 'src :' to 'src:'. I don't see a way to remove the warning about the background url.

Is this an example of the validation being too strict, or is the css written incorrectly?

This is all purely academic, just trying to understand how things work a bit better.

[Valloric]

These are probably bugs. Report them on the FlightCrew issue tracker (NOT on the Sigil tracker).

[cuthbert19]

I can't actually find the "background: url(...)" in the epub standard specificications (here) ... is it actually admissible? Maybe that's why the nook freezes?

[Perkin]

Shouldn't there not be a space between 'src' and ':' in the lines

src : url('../Fonts/OFLGoudyStM.otf')

AND

src : url('../Fonts/OFLGoudyStM-Italic.otf')

Edit:
Disregard as OP had done that already.

[Valloric]

"background: url..." is valid, but I'll have to check the CSS specs to see if whitespace is allowed between the colon and the "src".

[Perkin]

I read somewhere that having comments in the css could cause validation fails, if you remove the comment, does it check out OK then?

Edit:
See topic here, for more info
https://www.mobileread.com/forums/sho...d.php?t=108954

[ldolse]

The comments aren't contributing to the failure, though I did go ahead and try deleting them just to double-check for you. Valloric just posted a fix for this, looks like background and background-image weren't explicitly called out before in the reachability analysis.

[Jellby]

Originally Posted by Valloric

"background: url..." is valid, but I'll have to check the CSS specs to see if whitespace is allowed between the colon and the "src".

Actually, as cuthbert19 says, the spec lists "background-color", but not "background" (or "background-image"), which means it is not supported. Although it is strictly not an error, because in CSS unsupported properties are just ignored, so, from an ePUB perspective, it is like a harmless comment (except that it might be recognized by some readers).

As for the space, the CSS spec says:

A declaration is either empty or consists of a property name, followed by a colon (:), followed by a property value. Around each of these there may be white space.

[Valloric]

Originally Posted by Jellby

Actually, as cuthbert19 says, the spec lists "background-color", but not "background" (or "background-image"), which means it is not supported. Although it is strictly not an error, because in CSS unsupported properties are just ignored, so, from an ePUB perspective, it is like a harmless comment (except that it might be recognized by some readers).

True, but both Sigil and FlightCrew wouldn't be hurt by preparations for EPUB3. Yes, that spec is still a work in progress, but it won't be for long. I'd hate to start adding checks that I'll have to remove in a few months.

Originally Posted by Jellby

As for the space, the CSS spec says:

A declaration is either empty or consists of a property name, followed by a colon (, followed by a property value. Around each of these there may be white space.

Yes, I read that too after my last comment. I was pretty sure the space was allowed, but checking the spec can't hurt.

[Jellby]

Originally Posted by Valloric

True, but both Sigil and FlightCrew wouldn't be hurt by preparations for EPUB3. Yes, that spec is still a work in progress, but it won't be for long. I'd hate to start adding checks that I'll have to remove in a few months.

If I were doing a validator, I would issue a warning (not an error) at the use of any CSS property or value not supported in the spec. It shouldn't be too hard to later add an option to validate against other versions of the spec.

In Sigil, it would be nice if unsupported properties could be disabled, so that they don't show in the book view.