Re: [csswg-drafts] [css-fonts-5] Dynamic text size (#3708)

@tabatkins wrote:

> As @clshortfuse says, desktop browsers all respect the user's default font-size, and have for decades. Some pages break, but most are fine. 

I'd disagree that most are fine. Browsers all used to have an "enlarge text" method that most have abandoned because web sites implemented it so poorly. Now most browsers (including Safari) default to viewport zoom on the entire page, scaling images and block layout, too. The desktop viewport zoom you've mentioned ("most [sites] are fine") is directly equivalent to mobile viewport zoom, and so it's irrelevant to the font size discussion. This feature is already available on mobile via "pinch to zoom", "double-tap to zoom", and other ways.

Safari for Mac also retains a way to view the old "enlarge text only" behavior. Try it, and you'll see how much these CSS additions are needed. Either hold down "Option" while expanding the View menu, or use the hotkeys: Cmd+Opt+Shift+Plus/Minus. 

Almost every site I tried has overlapping text, and often horribly broken layouts, when you enlarge the text to its largest size: Yahoo, New York Times, Gmail, ESPN, Netflix, Hulu, CNN, Wikipedia, Amazon, etc. They're all broken. Only one of the sites I tried, BBC, adjusted its layout reasonably, and it took a page refresh to get it right. Some layouts would not be possible to adjust properly, even with current techniques of responsive web design.

> Is the mobile web so substantially different in this regard?

Yes, substantially, because the viewports and screens are so much smaller than desktop displays.

Standard viewport zoom is already available to mobile users through "pinch to zoom" and other means. Mobile browsers could automatically zoom the viewport to match the current system font size, but that would 1) cause excessive amounts of horizontal scrolling, and 2) provide absolutely no utility over existing methods of viewport zooming. 

If mobile browsers applied extra large system font sizes to mobile, it would break the layout of almost all web sites. The experience would be so bad that users would have to turn off the feature entirely while using the web. 

Native apps on mobile would similarly be broken if the large sizes were forced on them, so they aren't applied to apps automatically. App developers need to opt-in to supporting the larger font sizes. WWDC 2017 had a iOS-focused session on this called [Building Apps with Dynamic Type](https://developer.apple.com/videos/play/wwdc2017/245/).

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Received on Sunday, 31 March 2019 07:48:28 UTC