Man muss das auch etwas relativieren, da auch Microsoft das offenbar nicht konsistent umsetzt:
Zitat:
When an application calls the Rectangle function, the system draws the rectangle, excluding the right and lower sides if no world transformation is set for the given device context.
If a world transformation has been set by using the SetWorldTransform or ModifyWorldTransform function, the system includes the right and lower edges.
https://docs.microsoft.com/de-de/win...ing-rectangles