Mike Chambers

code = joy

Archive for the ‘javascript’ tag

Timing issues when animating with CSS3 Transitions

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I have been playing around a lot lately with motion graphics created using HTML5 and / or CSS3. One of my favorite new features is CSS Transitions, which makes it super simple to animate element properties between two states.

However, I ran into a gotcha the other day, and wanted to make a quick blog post in case anyone else runs into it in the future. Basically, if you change a property that a CSS Transition is monitoring in the same script loop that you add the element to the DOM, the CSS Transition will not take affect. Instead, the element will be drawn with the new properties, and will not animate to those properties.

Here is an example that shows the issue, as well as how to fix it.
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Written by mikechambers

July 20th, 2011 at 12:54 pm

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JavaScript Voronoi port

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I have always been amazed by some of the digital art work that Mario Klingemann (aka @Quasimondo has created using with Voronois. After doing some searching, I found an early ActionScript 1 Voronoi implementation that Mario did, and I ported it to JavaScript.

I wanted to share the results:
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Written by mikechambers

March 24th, 2011 at 12:19 pm

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JavaScript QuadTree Implementation

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Last week I was playing around with a little EaselJS experiment which required me to do collision detection against all items on the screen. This worked fine with a small number of items, but of course, the more items I added, the slower everything became.

I knew that I needed to optimize the code, and pare down the number of collision checks. I have done this before with a grid (even held a contest for it) and was going to port that AS3 code to JavaScript. However, Ralph Hauwert suggested I look at implemented a QuadTree, which should be more efficient.
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Written by mikechambers

March 21st, 2011 at 9:24 am

Example : Creating spiral designs with Canvas, JavaScript and EaselJS

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I have been having fun playing around with JavaScript, the HTML5 Canvas element and EaselJS lately, and have been building a lot of small experiments. I wanted to share a simple one I created, which creates spiral designs.

 

 

The example was pretty simple to put together, but is fun to play with, and can make some pretty nice patterns / spirals. I have uploaded a couple of images that I have created using the example:
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Written by mikechambers

February 9th, 2011 at 12:20 am

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PixelFlow : EaselJS / Canvas Dynamic Graphics Example

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If you have happen to have been watching my Flickr feed for the past week or two, you have probably noticed that I have been playing around with creating some graphics using Canvas and EaselJS. What started as a simple EaselJS experiment, quickly morphed into an excuse to build a mini app / example and play around with some of the new HTML5 and CSS3 features.

PixelFlow

 

The example I created (named PixelFlow) is a simple example / app that allows you to choose an image, and then create some designs using the colors from the image. The core drawing functionality is built about the HTML5 canvas element and the EaselJS library. It also leverages CSS3 transitions and transformation for animating the UI elements (loading and unloading).

You can play around with the example yourself at:
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Written by mikechambers

February 2nd, 2011 at 10:54 pm

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Detecting Canvas.toDataURL Support in Browsers

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I am wrapping up a code example that uses the Canvas.toDataURL API to save canvas data to an image. I am almost done, and was doing a final round of browser testing when I noticed that my example wasnt working on my Android based Google Nexus One Device (2.2.2). After some debugging, and then Googling, I discovered that the Canvas.toDataURL API is not implemented on Android (you can view the bug report here).

Well, after some cursing, I put together a simple method for detecting whether the API is supported on any particular device. I wanted to share it in case anyone else might run into a need for it. So, here it is:
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Written by mikechambers

February 1st, 2011 at 5:09 pm

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Setting the background color when generating images from Canvas.toDataURL

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One of the cool features of the HTML5 canvas element is the toDataURL method. This returns a Base64 encoded image in the form of a data url string. Among other things, this can be displayed directly within an IMG element on the page, or sent to the server so the image can be saved.

However, one thing that I found out this weekend is that there is no background color for the image returned from toDataURL. Looking at the actual canvas draft specification, I found this:
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Written by mikechambers

January 31st, 2011 at 1:37 pm

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EaselJS / Canvas Generative Graphics Flickr Set

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Just a quick note, but I have created a Flickr set which contains some of the generative graphics I have been creating using canvas, JavaScript and EaselJS.

You can view the set here.

I havent released all of the code used to create all of the examples, but I will release the code / examples as I finish them. Ill post new images on the set whenever I create something I think is interesting.

Written by mikechambers

January 26th, 2011 at 2:36 pm

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Layering Multiple Canvas Elements using JavaScript and EaselJS

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If you run my EaselJS Drone Follow example from yesterday on any non-Android / iOS computer / device, you may notice that a graphic is drawn between the mouse touch point and the current position of the drone. This is done by managing and drawing to two canvas elements and is provided to help make it clear what the drone is following (your mouse) and which direction it is currently heading.

Why use two canvas elements, instead of just drawing to one? Well, there are two primary reasons I architected the example like this.
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Written by mikechambers

January 25th, 2011 at 12:54 pm

Getting Started with the Canvas Element and EaselJS

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One of the features of HTML5 that developers are most excited about is the Canvas element. The Canvas element essentials provides a bitmap canvas for dynamically rendering shapes and bitmap graphics. It is very similar to the Flash Player’s Bitmap and BitmapData classes.

However, working with the Canvas element can be difficult, especially if you need to manage, update and or / animate multiple shapes and bitmaps. Unlike the Flash Player, the Canvas element does not have a concept of a display list or individual items to render. Instead, it provides a single Canvas on which to draw, and it is up to the developer to determine what needs to be rendered and when.

Grant Skinner has release a JavaScript library named EaselJS, which attempts to provide a Flash like DisplayList API in order to make it easier to work with the Canvas element. The library is just an alpha release, but is surprisingly full featured at this early stage. If you are interested in experimenting with the Canvas API, this is a great way to get started.
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Written by mikechambers

January 19th, 2011 at 3:48 pm

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