[webkit-reviews] review granted: [Bug 136907] Text laid out with the SVG -> OTF font converter does not have the same metrics as with the SVG font code path : [Attachment 238287] Patch

[bugzilla-daemon at webkit.org]

Darin Adler <darin at apple.com> has granted Myles C. Maxfield
<mmaxfield at apple.com>'s request for review:
Bug 136907: Text laid out with the SVG -> OTF font converter does not have the
same metrics as with the SVG font code path
https://bugs.webkit.org/show_bug.cgi?id=136907

Attachment 238287: Patch
https://bugs.webkit.org/attachment.cgi?id=238287&action=review

------- Additional Comments from Darin Adler <darin at apple.com>
View in context: https://bugs.webkit.org/attachment.cgi?id=238287&action=review


> Source/WebCore/svg/SVGToOTFFontConversion.cpp:221
> +    // If the font parser sees an ascent or descent of 0, it thinks that
something
> +    // bad happened and takes a different path. We want it to believe us.
> +    if (!ascent)
> +	   ascent = 1;
> +    if (!descent)
> +	   descent = 1;

Nothing in this comment makes it clear why “1” is a suitable value to use
instead of 0. Also “want it to believe us” is a vague comment. It would be more
useful to say something brief and clear about how specifying a 1 FUnit value
gives us the behavior we want.

> Source/WebCore/svg/SVGToOTFFontConversion.cpp:226
> +    // WebKit's SVG codepath hardcodes the line gap to be 1/10th of the font
size (see SVGFontData.cpp). We should match that.

This comment is missing the “why”. Why should we match that?

> Source/WebCore/svg/SVGToOTFFontConversion.cpp:683
> +    if (!advanceAttribute.isEmpty()) {

Why the special case for the empty string? The code would do the right thing
without a special case and I’d like this code better without a local variable
for advanceAttribute.

> Source/WebCore/svg/SVGToOTFFontConversion.cpp:702
>	       auto& advanceAttribute =
glyph.fastGetAttribute(SVGNames::horiz_adv_xAttr);

This code has the same issues as the copied/pasted version of it that I
commented on above.