Thursday, March 13, 2008

Using Expression DeepZoom

The key tool for building out MultiScaleImages we will use in Silverlight is Expression DeepZoom. DeepZoom is a Simple tool like Encoder for example that allows you to import images and produce the multi-layer image collections and tile structure used by DeepZoom (MultiScaleImages) in Silverlight to produce the coolness we are looking for.

DeepZoom (talk about double entendre) then creates a DeepZoom Project lets you import all the high resolution images you want to use. Then you can compose your collection of images and then it will export and build all of your multilayer image collections, tiles and other bits as configured. With that then we can embed these into Silverlight work with multilayered images.
We learn how to use the application by opening Expression DeepZoom and getting familiar with the user interface.

Currently the interface is pretty simple. We have our splash screen that pops up. That shows existing projects or lets you open new ones etc. We also can see the tabs which are basically the 3 steps to building a Multi layered image collection and getting it ready for Silverlight. From the top file menu we can open the project dialog.

Once we give our project a name and select the type (Seadragon Project) we then can start adding images to our multi-layered image collection. On the import tab in the UI we can see we have a view area and then a scrolllist of our images. At first this will be blank and at the bottom we have a button called 'Add Image.' If you click the 'Add Image' button you can use the standard windows API file dialog to find a cool high resolution image that you want to multi layer. If you add several you will see them on the design surface.

Now that we have added some images we can start arranging them in our collection. Start by click on the tab '2. Compose' at the top of the interface. Then you can drag the images from the right on to our design surface.

Let us take a look at the interface. At the top of the UI we can see a tool bar at the top and there are 5 tools which by default will have the first one selected. The first three icons represent the cursor state on the compose view of the application. The default is for dragging our icons onto the surface. Selecting second icon you can drag the design surface.

You can see how the map in the lower left of the composition surface has moved showing what the pan functionality looks like and this map shows you where on the surface that you are. The third icon on the compose tool bar is for zooming. This allows you to drill into any given location on the composition surface.

Looking closely we can see the drop down menus for the last two icons on the composition tool bar. You can see the second icon from the right is alignment items (i.e. left, right, top, bottom etc). if you select one then all your images get laid out in the collection accordingly. The menu for the last button that distributes images horizontally or vertically.

Once we get all our images on our composition surface we are ready to export our collection. There are a number of settings but for DeepZoom in Silverlight we are good with just having a location and exporting. We do this by clicking the export button.

DeepZoom then builds our Silver Dragon (SDI) file and builds out all over tiled images. If we are just going to use it for Silverlight and are using one image we can just grab its corresponding structure including the .bin, xml and the tile jpg's. Now we are ready to actually do Seadragon, er I mean SilverDragon, er I mean DeepZoom(MultiScaleImages).

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