Semantic zoom is a control used by apps in Windows 8 for displaying large sets of content in a truly user friendly format. Semantic Zoom is unique in that it provides an easy to navigate, touch optimized view of the data you present to users.
In designing Windows 8 we wanted to ensure users wouldn't have to pan tediously through large sets of content with touch. Semantic Zoom is our solution to this problem; it gives users the capability to jump quickly to sections in the view.
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