Kindle for iOS (AZK format) - line height issue

[heulwen.jones]

Hi there,

I am having an issue when I convert my Kindle to AZK format (for iOS) where within some paragraph there is a variation in line height from one line to the next.

This happens when a paragraph contains a quote which extends at least the full length of a line. To provide more detail:
1) Quotes appear in a span tag like <span class="Quote"> within the paragraph (paragraph enclosed in a <p> tag)
2) The font size of a quote (set in the CSS) is smaller than the font size of the paragraph, and the font is bold.
3) line-height is set on the paragraph class (<p> tag) but not on the quote class (<span> tag)
4) In this example the paragraph <p> font-size is 0.95em and line-height is 1.287em; quote <span> font-size is 0.803em

The Kindle Fire etc. is obeying the line-height of the paragraph regardless of span tags within the paragraph. However it appears to me that Kindle for iOS is not obeying the line-height of the <p> tag if the text in the <span> tag extends the full length of a line. Possibly it still does use the line-height set in the <p> tag (eg. 1.287em) but because all the text on the line is 0.0803em (instead of 0.95em) it recalculates the line-height based on this lower font-size value??

In other words it is like the Kindle Fire calculates line-height a paragraph at a time while Kindle for iOS calculates line-height a line at a time??

Does anyone have any ideas how to solve or workaround this issue?

Many thanks in advance for your help. Heulwen

[Notjohn]

The default line height on the Kindle platform is 1.2, I believe. (Whatever it may be, there IS a default line height.) Therefore I think it's unwise to specify a line height at all in your style sheet.

Keep it simple and let the defaults rule!

[heulwen.jones]

Unfortunately in this case I do need to specify line height : (

It seems to work fine on most Kindle devices, just an issue on Kindle for iOS?

[dgatwood]

Kindle actually (spottily) enforces a hard minimum of 1.2 for the line height, and ignores any line height that is smaller.

Worse, IIRC, some Kindle devices implement that limit incorrectly on some devices, resulting in the line height being calculated incorrectly if the font's ascender and descender don't add up to the em square, causing it to increase the line height to even more than 1.2x the font size because of the incorrect font height calculation.

If your line height is at least 1.2, I would suggest taking your fonts and running them through Fontographer or any other program that can automatically recompute the font metrics. (I think Adobe's font SDK might even be able to do this on its own.) See if that fixes the problem.

If you are trying to specify a line height less than 1.2, you'll have to find a different way to achieve the desired effect.

[JSWolf]

And then there are some fonts who's metrics can give you a smaller line height with a Kindle. So the suggestion to ignore line-height is a very good one.

[heulwen.jones]

Thanks guys for your help.

I suspect (I haven't tested yet) that even if I don't specify line height I am still going to have the same problem on the Kindle for ios - ie. lines within some paragraphs will have a smaller line height than other lines in the same paragraph when a span tag extends at least the full length of a line (containing a quote with a smaller font size), so the line height for that line is being calculated as less. This means I will still have varying line height across lines in a single parapgraph which is not so pretty : )

[dgatwood]

Originally Posted by JSWolf

And then there are some fonts who's metrics can give you a smaller line height with a Kindle. So the suggestion to ignore line-height is a very good one.

Hence my recommendation to open it in Fontographer and have it recompute the metrics.

[dgatwood]

Originally Posted by heulwen.jones

Thanks guys for your help.

I suspect (I haven't tested yet) that even if I don't specify line height I am still going to have the same problem on the Kindle for ios - ie. lines within some paragraphs will have a smaller line height than other lines in the same paragraph when a span tag extends at least the full length of a line (containing a quote with a smaller font size), so the line height for that line is being calculated as less. This means I will still have varying line height across lines in a single parapgraph which is not so pretty : )

You definitely should be using line height to fix that. However, it sounds like you're inadvertently setting it to less than 1.2x the (probably incorrectly) computed line height for one of the fonts. Try a larger value and see if the problem goes away.