Text opacity shows glyph overlap

[r12a]

This issue is likely to apply to all cursive script text.

When opacity is applied to text, Gecko and Blink produce dark patches where the cursive glyphs overlap, but Webkit and Legacy Edge don't. See the test.

For more details, see this GitHub issue, which is being used to track this gap.

[r12a]

The first comment in this issue contains text that will automatically appear in one or more gap-analysis documents as a subsection with the same title as this issue. Any edits made to that comment will be immediately available in the document. Proposals for changes or discussion of the content can be made in comments below this point.

Relevant gap analysis documents include: Adlam • Arabic/Persian • Kashmiri • N'Ko • UIghur

[svgeesus]

I would like permission to use the above image, or (better) the image in 3.4.7.2 Transparency, as an illustration in CSS Color 4, 13. Transparency: the opacity property. This is in response to the i18n review which suggested this be mentioned.

[shervinafshar]

@svgeesus, no objections here. Editors, please chime in if otherwise.

[r12a]

Updated the topic text to add a pointer to the CSS Fonts edit.

[svgeesus]

On https://w3c.github.io/i18n-tests/results/cursive#text_opacity instead of linking to https://drafts.csswg.org/css-color-3/#transparency it would be better to link to https://www.w3.org/TR/css-color-4/#transparency for several reasons:

• Color 4 is the current implementation target
• Color 4 is vastly better specified than Color 3
• Color 4 explicitly addresses glyph overlap and opacity, and has the arabic text example