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Re: Any official clarification on Text-only zoom and RWD?

for

From: Jonathan Avila
Date: Feb 29, 2016 10:28AM

> I'd be careful with the terminology, the browser does not 'change the width of the window', although I think I know what you mean.

What I meant was the window.innerWidth property changes when you zoom. It's equivalent to resizing the window with the caveat below.

> Think of zoom as basically increasing the CSS pixels, so if the browser
(inner) window is 1000px wide, and you zoom to 200%, the window will show 500px of the content.

The innerWidth will change AND the window.devicePixelRatio will also increase. This will cause the text size to increase even when a breakpoint has not been reached. So browser zoom such as the zoom in Chrome causes both a scale change and inner width change that in my opinion could cause unexpected issues in between breakpoints. That's why you'd need to test for zoom even when responsive design is used. You can see this by simply resizing your window and the innerWidth will change but the devicePixelRatio will not.

> Also, I think the wording of the current success criteria would still make that a fail, if you zoom in and the text doesn't increase in size, that's a fail.

Agreed.

>> I totally support text resize without zoom and believe it is a user
>> requirement and need.

> I am still not convinced, it is one of my questions to the Low Vision Task Force [3].

What I meant was I totally support and see the need for zoom without horizontal scrolling. It doesn't matter to me how it's done either through zoom or text resize -- as long as the text can be resized without horizontal scrolling. I think we agree on that.

Jonathan

Jonathan Avila
Chief Accessibility Officer
SSB BART Group
<EMAIL REMOVED>
703.637.8957 (o)
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