Customizing Rest

[今井雄治]

Hi users.

I want to customize rest by its duration, as following
    r4 --> black circle
    r8 --> black circle with under line

I tried following code.

--------
RestIV = {
    \once \override Rest #'stencil = #ly:text-interface::print
    \once \override Rest #'text = \markup {
        \halign #-0.7 \draw-circle #0.6 #0 ##t
    }
}

RestVIII = {
    \once \override Rest #'stencil = #ly:text-interface::print
    \once \override Rest #'text = \markup {
        \combine
        \halign #-0.7 \draw-circle #0.6 #0 ##t
        \filled-box #'(-0.2 . 1.0) #'(-1.4 . -1.1) #0
    }
}

\relative {
    e4. \RestVIII r8 e4 \RestIV r4
}
--------

I want to write like following.

--------
\relative {
    \CustomizeRest {
        e4. r8 e4 r4
    }
}
--------

Thank you.