About Deep Zoom Composer
With Deep Zoom Composer, you can take a collection of images of various resolutions (including large, high-resolution images) and arrange them into a composition. You can then export or publish the composition as either a single high-resolution image or a set of individual images with different resolutions. Once you export or publish your composition, you can use a standard broadband connection to quickly display and navigate a large, detailed image or a panorama of images that might otherwise be extremely slow to view.
A Deep Zoom image in a browser
What is Deep Zoom Composer used for?
There are many things you can do with Deep Zoom Composer, from artistic applications, such as complex photo mosaics, to business applications, such as photo galleries for real estate sites. Here are just a few potential uses:
Interactive online ads.
For more Deep Zoom examples online, see Seadragon Ajax on Microsoft Live Labs .
How does the Deep Zoom technology work?
Deep Zoom Composer uses the Deep Zoom technology found in Microsoft Silverlight and Seadragon Ajax. When you view an image created in Deep Zoom Composer in a browser, the browser downloads only the portion of the image that you are actually viewing on your screen at that time, and at a resolution appropriate to the scale of the image. Downloading only part of the image data at a time decreases the time it takes to load the image and optimizes the viewing experience.
For more information about Silverlight and Seadragon Ajax, see Exporting a composition.
When you first view a Deep Zoom image, your browser displays a scaled-up version of a low-resolution version of the image, and then blends in higher-resolution images as they are downloaded. This is the reason for the blurry-to-crisp experience when you view an image created in Deep Zoom Composer. It is also the reason that the Deep Zoom images open quickly regardless of the file size of the image. The blurry-to-crisp behavior that you see during loading also occurs when you interact with the Deep Zoom image (for example, zooming or panning the image), and it enables you to smoothly pan and zoom a Deep Zoom image the way you would an online map, such as Microsoft Live Earth.
Image pyramids and tiles
Each image in a Deep Zoom Composer composition is partitioned (or sliced up) into tiles. During the tiling process, Deep Zoom Composer creates an image pyramid of various resolutions. An image pyramid has the highest-resolution image, composed of multiple tiles, at the base of the pyramid, and the lowest-resolution image at the top of the pyramid, as a single tile. In Deep Zoom Composer, each tile at each level in the pyramid is 256x256 pixels. This tiling process happens at design time as part of the Deep Zoom Composer exporting process.
At run time (when you are viewing the image in a browser), one of the lower-resolution image tiles loads first to decrease wait time and download size so you can see the image as quickly as possible, instead of waiting for the entire image to load. As you pan and zoom the image, other pieces of image data are loaded as needed. For example, if you zoom in to see only the highlighted middle part of the image, your browser loads only the highlighted tiles, rather than the higher-resolution tiles of the entire image.
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