"Zoomed text node is not clipped with CSS overflow" [59br37]: Failed Example 3, 4, 5 satisfy the SC

[Jym77]

In a recent clarification to Understanding 1.4.4, this paragraph was added to the Intent:

Content satisfies the Success Criterion if it can be scaled up to 200% using at least one text scaling mechanism supported by user agents.

where the "text scaling mechanism[s] supported by user agents." are described in the previous paragraph as:

a number of mechanisms - including zoom (of the entire page's content), magnification, text-only resizing, and allowing the user to configure a size for rendered text.

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Failed Example 3 of Zoomed text node is not clipped with CSS overflow uses a media query to trigger a clipping at the 640×512px viewport, corresponding to 200% zoom of 1280×1024px "standard" viewport.

However, when increasing font size (in Chrome chrome://settings/font, in Firefox through the "zoom text only" setting), the viewport size does not change and the text does not clip, even up to 200% percent or more.

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See also w3c/wcag#3558 for a similar discussion in the other direction ("failed" examples that only fail by increasing font size, not by zooming, and therefore shouldn't fail).

[Jym77]

Looking a bit more into it.
Out of the 5 Failed examples, I feel that only Failed Example 2 is really "good", with Failed Example 1 being "correct".

Failed Example 1 is already clipping its text without any zoom. It is true that zooming does clip even more content (because more is pushed on the second line that is clipped). So it is a WCAG failure. But I think we should craft it so that there is no content loss at 100%, but there is some at 200%. Otherwise, it is not really a "real world" example; I feel these would be caught early in visual regression tests, typically.

Failed Example 4, and 5 are already clipping their text without any zoom. Zooming (e.g. using Chrome built-in zoom) does not really clip more of it (the size are smalls and some step effect sometimes occurs, but by making the container a bit larger this disappear). Since the zoom doesn't clip more than what is already clipped, I'm doubting that this actually fails 1.4.4 (There is no "loss of content" due to resizing since that content is already lost).