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[csswg-drafts] [css-inline] A question for the procedure to compute the used value of "line-height" (#3749)

From: joonghunpark via GitHub <sysbot+gh@w3.org>
Date: Wed, 20 Mar 2019 00:23:35 +0000
To: public-css-archive@w3.org
Message-ID: <issues.opened-423011864-1553041414-sysbot+gh@w3.org>
joonghunpark has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-inline] A question for the procedure to compute the used value of "line-height" ==
I have a question about the procedure to compute the used value of "line-height".
I'm currently making a change on blink in
https://chromium-review.googlesource.com/c/chromium/src/+/1522053/3.
This change is for "line-height" to return used value instead of "normal keyword"
as resolved value.

In case of WebKit, fontMetrics().lineSpacing() value is used instead of 'normal' as below.

int RenderStyle::computedLineHeight() const
{
    const Length& lh = lineHeight();
    // Negative value means the line height is not set. Use the font's built-in spacing.
    if (lh.isNegative())
        return fontMetrics().lineSpacing();
    if (lh.isPercentOrCalculated())
        return minimumValueForLength(lh, computedFontPixelSize());
    return clampTo<int>(lh.value());
}

And Firefox returns used value "px" instead of "normal" also.

But I'm not sure what is the exact procedure to compute the used value for "line-height",
because I coundn't find that in spec.

Is it ok to use font metircs linespacing value like WebKit, or is there a exact procedure to compute the used value?

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/3749 using your GitHub account
Received on Wednesday, 20 March 2019 00:23:36 UTC

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