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Zoom content updates

From: Alastair Campbell <acampbell@nomensa.com>
Date: Thu, 25 May 2017 23:45:07 +0000
To: WCAG <w3c-wai-gl@w3.org>
Message-ID: <DB6PR0901MB091966CC4873850B08B224DEB9FF0@DB6PR0901MB0919.eurprd09.prod.outlook.com>
Hi everyone,

Based on the call earlier I've made some updates to the SC text:
https://github.com/w3c/wcag21/issues/77

The main change is to switch from saying "allow for this much zoom", to saying "ensure it works at this width".

The main reason for this is for testability, as soon as you say it should not create horizontal scrolling then you need to define either: 
- The starting size (e.g. 1280px) and the zoom factor (400%), or
- The end size (e.g. 320px).

None of these values were in the SC text, so for testability we'd have to include either:
"Starting at 1280px zoom content by 400% without loss of...", or
"Content can be displayed at a minimum width of 320 CSS pixels without loss of..."

I think the second approach is more effective, and if it starts with "Zoom content", it still has a connection to the user-requirement. It also side-steps the (perceived) issue of how you test on smaller screens.

So the SC text is now:
------------------
Content can be displayed at a minimum width of 320 CSS pixels without loss of content or functionality, and without requiring scrolling in the direction of text except for parts of the content which require two-dimensional layout for usage or meaning.

Note: The width of 320 CSS pixels is equivalent to a browser width of 1280 pixels wide at 400% zoom.

Note: Examples of content which require two-dimensional layout are images, maps, diagrams, video, games, presentations, data tables, and interfaces where it is necessary to keep toolbars in view while manipulating content.
------------------

I just added the first note, I'm not wedded to it, do you think we need it or can we explain that in the understanding?

Any comments here please:
https://github.com/w3c/wcag21/issues/77

Cheers,

-Alastair
Received on Thursday, 25 May 2017 23:46:12 UTC

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