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The spec states "For historical reasons, the coordinates must be interpreted relative to the displayed image, even if it stretched using CSS or the image element's width and height attributes." This wording is ambiguous about various scaling mechanisms and how they do or do not affect scaling of image map regions. Images may be scaled by HTML attributes, author CSS, user CSS, browser zoom, and perhaps other mechanisms. The HTML accessibility task force could not achieve a common interpretation of which scaling mechanisms would be applied before overlaying the image map with the areas relative to the resized image, vs which scaling mechanisms would be applied in such a way that imagemap areas would scale along with the image. If this is interpreted inconsistently, it will lead to major accessibility and usability problems on sites. Therefore this statement needs clarification and expansion to address all use cases clearly. We will attempt to provide suggested wording as a follow-on comment to this bug.
I think the correct approach here is: - Scaling from CSS width/height (regardless of source) and the img width and height attributes is applied before interpreting the image map coordinates. - Scaling from CSS transforms or UA-controlled zoom features (such as a UI-level full-page zoom feature, or something like iOS punch-to-zoom) are applied after interpreting the image map coordinates. The reason for applying UA features after interpreting the image map is that sites have no way to account for this. The reason for applying CSS transforms after interpreting the image map is that there is no legacy behavior to preserve in this case, and CSS transforms can also impose translation, rotation and skew which should definitely *not* be applied.
mass-move component to LC1
EDITOR'S RESPONSE: This is an Editor's Response to your comment. If you are satisfied with this response, please change the state of this bug to CLOSED. If you have additional information and would like the editor to reconsider, please reopen this bug. If you would like to escalate the issue to the full HTML Working Group, please add the TrackerRequest keyword to this bug, and suggest title and text for the tracker issue; or you may create a tracker issue yourself, if you are able to do so. For more details, see this document: http://dev.w3.org/html5/decision-policy/decision-policy.html Status: Accepted Change Description: see diff given below Rationale: Concurred with comment 1.
Checked in as WHATWG revision r6503. Check-in comment: Be more precise about what counts as scaling for image map coordinates. http://html5.org/tools/web-apps-tracker?from=6502&to=6503