The usage of IWindowSystem become fullfiled with problems when switches between GAPIs. The main reason is differences between back buffers implementations per GAPI. For DirectX it makes no sense, but OpenGL works with client area only.
So the solution is to clarify and unify pipeline of usage GetWidth and GetHeight for IWindowSystem. Now they will mean client area's sizes and outter sizes of the window will be bigger.
Description
The usage of IWindowSystem become fullfiled with problems when switches between GAPIs. The main reason is differences between back buffers implementations per GAPI. For DirectX it makes no sense, but OpenGL works with client area only.
So the solution is to clarify and unify pipeline of usage GetWidth and GetHeight for IWindowSystem. Now they will mean client area's sizes and outter sizes of the window will be bigger.