Bug 260342

Summary: clip-path on SVG content should default to using the border-box (aka stroke-box)
Product: WebKit Reporter: Philip Rogers <pdr>
Component: SVGAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal CC: sabouhallawa, simon.fraser, webkit-bug-importer, zalan, zimmermann
Priority: P2 Keywords: InRadar
Version: Safari Technology Preview   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Testcase showing two clip-paths that should render the same none

Description Philip Rogers 2023-08-17 04:34:24 PDT 
Created attachment 467305 [details]
Testcase showing two clip-paths that should render the same

In the attached testcase we have 2 stroked green boxes with clip-paths of "inset(0)" and "inset(0) border-box". These should render the same due to the following lines in http://www.w3.org/TR/css-masking-1/#the-clip-path:
1. If no reference box is specified, the border-box will be used as
  reference box.
2. For SVG elements without an associated CSS layout box, the used
  value for ... border-box and margin-box is stroke-box.

I found this while working on bringing Chromium's clip-path implementation up to speed and found no engines agree on this. I plan to land two new WPT tests covering this behavior (css/css-masking/clip-path-svg-content/clip-path-inset-stroke-001.svg and css/css-masking/clip-path-svg-content/clip-path-inset-stroke-002.svg).
Comment 1 Radar WebKit Bug Importer 2023-08-24 04:35:15 PDT 
<rdar://problem/114375393>