[R] interactive image graphic

[Abelian]

Dear All
I want to plot a kind of figures, which can interactive with user.
For example, i have a matirx which can be showed by image function.
i.e. we can compare the value depend on different colors.
However, the change of colors depend on the range of value.
Nowaday, i want to set a bar, which can be moved by user such that the
user can obtain the appropriate range.
Does anyone suggest me which function can be applied to solve this
problem?
Thanks