le accidental occurrence

The touch-enabled sliderControl covered earlier is an easy UI widget to select a value from a set or a range of numbers.  It can be easily modified to function as a slide-to-unlock contorl that you see on the iPhone.  Enter the slideToAction control:

mySlider6 = new slideToAction('#slider6', ['slide to unlock'], {
	onchange: function(){
		alert('unlocked'); // some useful action!
	}
});

Markup:

<div id="slider6" class="slider"></div>

When the thumnail is moved all the way to the end, the onchange handler gets called.  Simple.  slideToAction inherits all of sliderControl’s kenetics and emulates the spotlight effect of iPhone’s control.

slideToAction is included as part of sliderControl.  See item #6 ‘single value slider’ on the demo page.

(The thumbnail looks better on the iPhone browser!)

The spotlight effect of the label text is achieved using -webkit-mask-* CSS attribute and animating the -webkit-mask-position property.  Here’s the CSS:

.sliderAction .sliderLabel {
	font-size:18px;
	font-weight:normal;
	text-shadow:none;
	color: #fff;
	-webkit-mask-image: -webkit-gradient(linear, 35% top, 65% top,
           from(rgba(0,0,0,.20)), color-stop(.5,rgba(0,0,0,1)), to(rgba(0,0,0,.20)));
	-webkit-mask-size: 50%;
	-webkit-mask-repeat: none;

	-webkit-animation-name: spotlight;
	-webkit-animation-timing-function: linear;
	-webkit-animation-duration: 1500ms;
	-webkit-animation-iteration-count: infinite;
}

using the animation keyframes:

@-webkit-keyframes spotlight {
    from {-webkit-mask-position: 0;}
    to {-webkit-mask-position: 100%;}
}

The  -webkit-mask-position property is animated on desktop Safari 4.x and Chrome 4.x.  It isn’t supported on iPhone OS 3.1.2 browser… but hopefully it will under 3.2.

Update: (11 March 2010)

New version 0.1a has an updated slideToAction() that looks more like the real thing.  Here’s a screenshot.

Seems like SDK developers have been trying to get this feature implemented as well.  See here and here.