ShapeDrawingOptions Draw methods do not allow transparent background
When drawing on the map, particularly with PointType = tkPointSymbolType.ptSymbolPicture, the image is, by default, drawn with transparent background. However, when drawing directly to a specific device context through the ShapeDrawingOptions DrawPoint (or DrawPointVB) methods, you have to specify a background color, and there is no option to draw with a transparent background.
Recommendation: Add an optional parameter to the various Draw methods, allowing for a specific background alpha value, to be applied to the already specified background color. The parameter should default to 255, fully opaque, so that current behavior is not modified for existing applications that do not specify the new parameter.
Implementation: All public Draw methods exposed by the ShapeDrawingOptions class now support an additional optional parameter, being a byte alpha value. This new parameter defaults to 255 so that the solid background behavior is not changed for existing applications.
The primary reason to use this new parameter would be to set a transparent background for the image/drawing, and this could have been done with a simple boolean value indicating whether or not to draw with a transparent background. However, it seemed that allowing for the alpha component provided the most flexibility to the caller.