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HTML5 assault on Adobe Flash heats up with ClickToFlash

Porting Flash to the mobile

Existing Flash projects will require some additional work to get them on the iPhone; Adobe notes the iPhone's 320x480 resolution is not the target resolution of most Flash apps aimed at web users, and that touch navigation will not work with content designed around the use of a precise mouse pointer.

"Certain behaviors that you may often employ in desktop application development will not necessarily apply to the iPhone," writes Adobe spokesman Aditya Bansod in a blog posting announcing the new tools. He also warns, "The iPhone is most decidedly not a desktop computer. It has very powerful and sophisticated hardware, but there is a wide spectrum of capabilities between the different generations of device, the amount of memory available, and the amount of processing power your application has at its disposal."

Adobe's Applications for iPhone FAQ further notes, "The iPhone and iPod touch have processors significantly slower than those found on most desktop PCs and Macs. Thus, content may run slower than it does when running on a desktop personal computer. However, the exact differences will depend on the specific content."

The many faces of Flash

Adobe also states that any Flash content intended for conversion to an iPhone app must use ActionScript 3.0, which debuted with Flash 9. Previous versions of Flash used ActionScript 1.0 or 2.0, which are run using an entirely different virtual machine compared to ActionScript 3.0. The desktop Flash plugin supplies two different virtual machines, one for playing existing ActionScript 1/2 bytecode, and a second for executing ActionScript 3.0.

Adobe's existing version of Flash Lite 3.0 for mobiles only supports ActionScript 2.0, which means Flash Lite can't run modern Flash 9 or 10 content. The new Flash 10 player Adobe is aiming at mobile users over the next year will only run ActionScript 3.0, which conversely means that legacy Flash content designed to work with Flash Lite won't work on new devices.

This diversity helps balloon the desktop version of Flash, which makes no effort to force the adoption of modern Flash content because it has the resources available to run legacy content using multiple virtual machines. But that doesn't translate to the mobile realm, where battery life and processing power constraints make the fat desktop Flash plugin and its pair of virtual machines unworkable.

Adobe's plans to ship a "full" mobile version of Flash 10 that only supports new 3.0 bytecode will suddenly obsolesce all existing Flash content that is more than a couple years old. That includes anything designed to work with Flash Lite, Adobe's current mobile strategy. That will force mobile Flash developers to rewrite all of their Flash code in order for their content to work with the new mobile player, undermining a key reason for wanting to use Flash in the first place: its wide installed base.

History of Flash Player

Additionally, with the iPhone consuming around half of all mobile web traffic, mobile Flash developers will have to contemplate whether it's worth it to rewrite all their existing Flash content in ActionScript 3.0 just to target the non-iPhone platforms that should be able to run Flash Player 10 by sometime over next year.

The alternative is to build HTML5 apps using standard JavaScript, which already runs on the iPhone and on other WebKit mobile browsers such as those for Nokia's Symbian, Google's Android, RIM's BlackBerry OS, and Palm's WebOS.

Such open content will not only work on the iPhone and BlackBerry, but will also run on desktop browsers including WebKit browsers such as Safari and Chrome; Mozilla's Firefox; Opera; and even Internet Explorer using Google's Chrome Frame plugin.

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Daniel Eran Dilger is the author of "Snow Leopard Server (Developer Reference)," a new book from Wiley available now for pre-order at a special price from Amazon.