Bug 257746

Summary: Text opacity shows glyph overlap for cursive scripts
Product: WebKit Reporter: r12a <ishida>
Component: TextAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal CC: mmaxfield, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: Safari 16   
Hardware: Unspecified   
OS: macOS 12   
Description Flags
N'Ko text showing no overlaps in opaque cursive text none

Description r12a 2023-06-06 07:07:08 PDT
Created attachment 466603 [details]
N'Ko text showing no overlaps in opaque cursive text

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

Text in 'cursive' writing systems is joined by overlapping glyphs with the appropriate joining forms. If those glyphs are made opaque, the joins should not become apparent. For example, N'Ko should look like shown in the attached image.

css-color was updated to clarify that opacity should be applied to a whole element, not to individual letters, so that this shouldn't happen.

WebKit works as expected for Arabic, Devanagari, Syriac & N'Ko, but not for Adlam (Fulah), Mongolian, or Hanifi Rohingya.

It seems that a fix has been applied for certain scripts, but needs to be extended for those mentioned (plus Mandaic).


Interactive test, Applying opacity to cursive text doesn't produce dark patches where glyphs overlap

I18n test suite, Text opacity
Comment 1 Radar WebKit Bug Importer 2023-06-13 07:08:17 PDT