Changing numbering style in subfigure 更改subfigure編號方式

Q. How to change numbering style in subfigure?

1. in subfigure show 12.1:, 12.2:, in ref show 12.1, 12.2.
#put the following code in preamble.

\renewcommand{\thesubfigure}{\roman{subfigure}}
\makeatletter
\renewcommand{\@thesubfigure}{(\thesubfigure)\space}
\renewcommand{\p@subfigure}{\thefigure}
\makeatother

2. in subfigure show (i), (ii), in ref show 12i, 12ii.
#put the following code in preamble.

\renewcommand{\thesubfigure} {\thefigure.\arabic{subfigure}}
\makeatletter
\renewcommand{\@thesubfigure}{\thesubfigure:\space}
\renewcommand{\p@subfigure}{}
\makeatother