w3c/csswg-drafts

[cssom-view] It is unclear when offsetX/Y are calculated

Open

#1,070 opened on Mar 1, 2017

View on GitHub
 (22 comments) (0 reactions) (0 assignees)HTML (3,546 stars) (545 forks)batch import
Help Wantedcssom-view-1

Description

https://drafts.csswg.org/cssom-view/#extensions-to-the-mouseevent-interface

The spec says "return the x[y]-coordinate of the position where the event occurred relative to the origin of the padding edge of the target node, ignoring the transforms that apply to the element and its ancestors, and terminate these steps."

blink and webkit cache the value at the first access, Edge seems to cache it when event is created and Gecko calculates it always. My reading is that Gecko does it right, bz' reading is that Edge does it right, but then, blink/webkit model is the fastest.

Contributor guide

Tech stack
javascripthtmlcss
Domain
frontenddocumentationapi
Issue type
documentation
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
unclear
Prerequisites
CSSOM View specbrowser event modelspecification process
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
15
Research direction
Examine the CSSOM View specification at https://drafts.csswg.org/cssom view/#extensions to the mouseevent interface. Review browser source code to understand caching behavior in Blink, WebKit, Edge, and Gecko. Comment on the spec to clarify when offsetX/Y should be computed relative to padding edge ignoring transforms.