Bug 239693 – locale:zh-*** causes text emphasis marks to draw too far from their base text

• Status: NEW
• Component: Layout and Rendering

[Bobby (Fu-Hsin) Tung]

Created attachment 458218 [details]
test case with multiple languages and fonts

Hello,

When I tested CSS property 'text-emphasis' in Japanese and Chinese language. I found that layout will be adjust to let the dot above/aside close to base text with certain fonts: Hiragino Mincho and Hiragino Sans. When I changed the value to sesame and circle, some other Japanese fonts may work. But it didn't apply to Traditional Chinese and Simplified Chinese.

Without the layout adjustment, the dot may far away from base text, even make line-height expand with a proper value 1.7 / 1.8.

I'm not sure this behavior related to font, or Webkit had a whitelist to adjust those fonts.

text-emphasis is not only used in Japanese, It's official punctuation in China[1] for Simplified Chinese. And it also occasionally used in Traditional Chinese books published in Taiwan, especially translated from Japanese.

I'd like this layout adjustment able to apply for more language and fonts. 

Regards, 

Bobby

[1]: In China National Standard GB/T 15834—2011.

[Radar WebKit Bug Importer]

<rdar://problem/92567329>

[Myles C. Maxfield]

I'm having trouble understanding this bug report. Is this bug report about the size of the circle in this:

<p class="hiraginosans">それは<em class="circle">傍点</em>という記号。（hiragino sans）</p>

compared to the size of the circle in this:

<p class="yumincho">それは<em class="circle">傍点</em>という記号。（yu mincho）</p>

?




Or is this bug report about the distance from the dot to the base text in this:

<p class="source">それは<em>傍点</em>という記号。（source serif jp）</p>

compared to the distance from the dot to the base text in this:

<p lang="zh-Hant-TW">這是<em>著重號</em>。（songti tc）</p>

?

[Bobby (Fu-Hsin) Tung]

Hello Myles, 

Size and Distance are different between font. But distance from the dot to base text is more important because in real case of Tradition Chinese ebook. It will expand line-height with a normal value 1.7.

Size of the dots (dot / circle / sesame...) varies with fonts. Some are to small to be noticed by reader. I'd like to figure out what made the difference. But apparently, It may not layout engine's issue.

Regards,

Bobby

[Myles C. Maxfield]

> distance from the dot to base text is more important

Okay, thanks for the clarification. I'll retitle this bug to make this a bit more clear.

> I'd like to figure out what made the difference.

The shape you see is a glyph from the font. It's the font file's responsibility to size the glyph.

In https://drafts.csswg.org/css-text-decor/#propdef-text-emphasis-style the spec indicates:
> circle
> Display large circles as marks. The filled circle is U+25CF '●', and the open circle is U+25CB '○'.