Gets the position of the top edge of the viewpoint in the text rendering coordinate system.
Assembly: Microsoft.VisualStudio.Text.UI (in Microsoft.VisualStudio.Text.UI.dll)
This property is read-only. The value can be either positive or negative. When the viewport layout is only partially changed, ViewportTop is increased or decreased by the number of pixels up or down that the view has been scrolled. When the viewport layout is completely changed (such that all of the lines of the previous layout are changed), ViewportTop is reset to 0.0.