With Metro, Windows 8 will be giving app developers a whole new platform and a new UI to work with. However, these apps should always offer their users good performance as well. In the latest post on Microsoft"s official Windows 8 app developer blog, the company"s Dave Tepper gives some tips to app makers on how to avoid some performance problems in their Metro-based creations.
Tepper first gives some general advice to increase an app"s performance, such as having the app load local images and files, rather than having them load over a network. He also says that if an image is supposed to be viewed well at multiple resolutions, it"s best to have multiple versions of that image "unless you have a strong reason not to."
He also states that a Metro app should have content appropriate to the user"s resolution, stating, "Loading content that is too small for a user’s resolution has reduced fidelity. Loading content that is too large for a user’s resolution puts an unnecessary strain on the resources of the system."
When creating Windows 8 Metro apps in JavaScript, Tepper says that having thumbnails in place, via using the Windows Runtime thumbnail APIs, will help make the app run faster. He posts some example code to show how this feature will work. Keeping communication between the DOM and the JavaScript engine down to a minimum will also help increase a JavaScript-based app"s performance.
If an app maker is using XAML for his Metro creation, Tepper says that only loading the XAML code that is needed to get through the startup process will speed up performance, saying, "The easiest thing to do is load only pages needed to display the first visual. Carefully examine the XAML of your first page to make sure it contains everything it needs. If you reference a control or style that is defined somewhere else, the framework parses that file too."