AspectRatioGets the aspect ratio used by the viewportHeightGets or sets the height dimension of the viewport on the render-target surface, in pixels.MaxDepthGets or sets the maximum depth of the clip volume.MinDepthGets or sets the minimum depth of the clip volume.TitleSafeAreaReturns the title safe area of the current viewport.WidthGets or sets the width dimension of the viewport on the render-target surface, in pixels.XGets or sets the pixel coordinate of the upper-left corner of the viewport on the render-target surface.YGets or sets the pixel coordinate of the upper-left corner of the viewport on the render-target surface.
x,y起点位置   height,width宽度和高度, maxdepth,mindepth，Z值深度缓存、