Nearest Non-Null (by nearest x scale value)
TimeValue
CPU
----
RAM
----
Nearest Non-Null (by 30px proximity)
Value
--
Value
--
Value
--
Value
--
Value
--
Nearest Non-Null (by 15px proximity only when hovered val === null)
Time
--
Value
--
Value
--
Snap hover points and cursor to previous non-null
Value
--
foo
--