The range of valid values for both the X and Y components is between 0.0 and 1.0, inclusive, and represent a vector expressed relative to the upper left corner of the area in which the gradient is displayed.
A value of zero represents the leftmost/topmost point of the area in which the gradient is displayed; a value of one represents the rightmost/bottommost point.
Any value between 0 and 1 is interpreted as a ratio which describes the location as relative to the top left corner of the area in which the gradient is displayed.
For example, given an area that is 100 pixels square, a value of (0.5, 0.25) coincides with the coordinate (50, 25).
In the absence of an explicit setting, the value of this property resolves to (1.0, 0.0).
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2