CSS3 Pullout Menu

This demo is for a folding pull-out menu that uses CSS3 elements and JavaScript only. It uses no images or flash to produce the effect although they could be used to enhance the natural feel.

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The Idea

I’ve seen this effect used before but most recently in a tech demo for Microsoft’s “Courier”. Below is a snippet of how this menu system works:
Pullout Menu Design
My Idea was to build this using DHTML only. No Flash, Canvas or SVG but pure HTML, CSS and JavaScript.

The Basis

The Pullout menu comprises of five HTML elements a,b,c,d and a handle. Elements a,b,c,d are positioned and then skewed to give the effect of a folding object.
folding object
When the handle is pulled outwards the width of the elements is stretched and the skew becomes less. This and some colouring effects in JavaScript give the effect of a fold.

Final Effects

I added a simple “on complete” event that detects when the menu is fully opened. The event can be used to trigger any JavaScript you like. I also tinkered with a revert animation that was triggered if the menu was released without being fully open, although this was cool it made it impossible to view the code frame-by-frame in firebug.

Folding Improvements

The animation I used doesn’t seem natural to me, this was down to my lack of understanding in perspective drawings and transitions. Im sure someone with a better understanding could make a much better example from this concept. Maybe if images, gradients and shadows were introduced the effect would start to feel more natural.

Finally

If anyone does improve the menu could you let me know. I’d be really interested to see it.

Flipping Crazy – CSS3

This is a pseudo way to flip HTML elements on their backs. This is a way of doing it now without waiting for a possible introduction of 3D Transforms from webkit.

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About Flipping

I first used flipping a few years ago when building touch screen HTML applications for kiosks. The animation would basically make the elements width 0 whilst moving the elements position right. This would give the effect that the element had been “sort of” flipped. It was a very simple solution and would only work if the animation was fast. Tricking the human eye into thinking it was actually flipped.

So what’s changed

Well firstly CSS3 allows you to skew, not screw! but skew. Skew allows you to give a simple pseudo 3D effect. It’s not ideal for this example but until 3D Transforms come in, it greatly adds to the effect of tricking the eye into thinking the element has been flipped.

The Process

The animation works in three steps:

The first step goes from: [width: curWidth, left: 0, skew: 0deg 0deg] to: [width: 0, left: initialWidth/2, skew: 0deg 20deg]. This gives the effect that the element has been flipped like a playing card onto its thinnest edge, essentially you cannot see it at this stage.

The second step triggers any javaScript you want to happen. In my examples I add a class to the element called “toggleTrue” which can be used to change the CSS properties of the box. Potentially videos, images or text could be inserted creating a sort of flipping lightbox.

The third and final step animates the element from it’s side to it’s back-facing plane. The animation goes from: [width: 0, left: initialWidth/2, skew: 0deg -20deg] to: [width: initialWidth, left: 0, skew: 0deg 0deg]. Notice the skew changes from step one’s finishing position to a negative value, without doing this it looks as if the card has gone 90deg and back again.

Flipping an element with background-image set:

When I initially did this a few years ago I would use an image tag and just flip that. This was because changing the width of an image stretches the image and using background-image wouldn’t do that, until now that is. By using the CSS3 property “background-size” I can set the width to 100%, this makes the background-image stretch as the container does.

Why not use CSS3 animation in webkit?

I did experiment with CSS3 animations and failed quite quickly. The problem i found was the absence of a javaScript callback method. There might be one but I couldn’t work out how and without a callback, CSS animations seem quite useless to me.

I also tried using CSS3 3D transforms. This looks much better than skew because the element is actually flipped – No moving the elements position, no tricks of the eye, no fakery! The problem was that JavaScript manipulation of these CSS3 3D transforms seemed to create some crazy artefacts in the picture.

Finally

Take a look at the code in firebug and see how it works. If you know how to use firebug’s console try setting the effects speed using “effectSpeed = 1000;”. This slows the animation down. Please leave your comments and thoughts below.