any special code when deal with Width but not Height? when resize window by Width the object behave different from resizing by Height...

any special code when deal with Width but not Height? when resize window by Width the object behave different from resizing by Height…
eg. when only resize by Width, esp. when the window width reach and become smaller than the object’s width, the object not scaled and the left/right part of the object was not seen in the window.
but only resize by Height, the above will never happen, as the object will scale down to make sure the whole object is always seen in the window no matter how small the window is.
Thanks!