None ：The content preserves its original size.
保持原始尺寸。
Supported by Silverlight for Windows Phone
Fill： The content is resized to fill the destination dimensions. The aspect ratio is not preserved.
縮放到目標尺寸，寬高比不會保留。
Supported by Silverlight for Windows Phone
Uniform：The content is resized to fit in the destination dimensions while it preserves its native aspect ratio.
縮放到目標尺寸之內，並保持原始寬高比。
Supported by Silverlight for Windows Phone
UniformToFill：The content is resized to fill the destination dimensions while it preserves its native aspect ratio. If the aspect ratio of the destination rectangle differs from the source, the source content is clipped to fit in the destination dimensions.
保持原始寬高比進行縮放，以填充。如果兩者的寬高比不同，源會被剪切掉多餘的部分。