art with code

2011-08-29

Canvas image filter library

Here's a small image filter library for the canvas element: github.com/kig/canvasfilters

It's based on the HTML5Rocks Canvas Image Filters article.

2011-08-27

WebGL Filesystem Visualizer


I put the HTML5WOW 3D filesystem visualizer demo online at fhtr.org/wfsv. Works only on Chrome as it uses the file input webkitdirectory attribute to recursively list directory contents.

Use the file input button in the top-left corner to select a directory to visualize. The visualizer tries to generate a model of the full directory tree, so it only works on small dir trees (less than 500 files or so). Use the console to navigate by clicking on file names. You can also use some shell commands like ls, cp, rm and mv. The filesystem contents aren't modified though, only the visualization.

Here's a video of the visualizer in action from the Google I/O 2011 "HTML5: The Wow and the How"-presentation:

2011-08-19

Ken Burns effect using CSS


The Ken Burns effect is a special effect used in documentaries when you only have a static photograph of an interesting item. To add some movement and life to the photograph, you zoom into the photo and pan towards a point of interest. It's named the Ken Burns effect because it was used a lot by a documentary film maker named Ken Burns.

Anyhow.

You can achieve the Ken Burns effect using CSS animations. It's not even particularly difficult. Just create a div with overflow:hidden to hold the image, then change the image's CSS transform property. Or if you want to be totally retro and backwards-compatible, you could also achieve the effect by changing the image's top, left, width and height using a JS setInterval.

So, CSS:

.kenburns {
overflow: hidden;
display: inline-block;
}
.kenburns img {
transition-duration: 5s;
transform: scale(1.0);
transform-origin: 50% 50%;
}
.kenburns img:hover {
transform: scale(1.2);
transform-origin: 50% 0%; /* pan towards top of image */
}


And the corresponding HTML:

<div class="kenburns" style="width:640px; height:480px;">
<img src="image.jpg" width="640" height="480">
</div>


If you hover over the image, it will slowly zoom in and pan towards its top edge.

You can see the effect in action here. And a more complex version with a JS-driven lightbox here.

The (quick, hacky) code is on GitHub.

2011-08-11

Spinner library


Ok, uploaded the spinner library to GitHub. There's a demo page too. It's a wee bit buggy though. I think the transition events are not firing when the page is hidden.

Even getting it to the current phase was a pain, the interaction between CSS transitions and animations, the DOM, JavaScript and events is flaky at the edges. Once I get an animation or transition going, it works well. But if I want to change some CSS properties in JS with the intent to trigger an animation or transition, it's pretty much guesswork whether it will actually work without glitches.

Hmm... As a workaround, I think I could just create a new element on every show/hide-cycle. That way the animation can't possibly fire one 100% frame before starting from 0%, right?? (This happened on Firefox... or maybe it was an unanimated frame or something. I ended up switching from animations to transitions because of that.)

On Chrome Canary, border-radius and overflow:hidden don't behave like you'd expect. Instead of clipping the contents to the rounded box, it clips on the rectangular box. I don't know why. And sometimes the rendering flickers when using transforms that toggle HW compositing for the page.

About Me

My photo

Built art installations, web sites, graphics libraries, web browsers, mobile apps, desktop apps, media player themes, many nutty prototypes, much bad code, much bad art.

Have freelanced for Verizon, Google, Mozilla, Warner Bros, Sony Pictures, Yahoo!, Microsoft, Valve Software, TDK Electronics.

Ex-Chrome Developer Relations.