format args doesn't take effect in visual mode

[xtrats]

my config:

let g:neoformat_enabled_c = ['astyle']
let g:neoformat_c_astyle = {
            \ 'exe': 'astyle',
            \ 'stdin': 1,
            \ 'args': [
            \     '--style=linux',
            \     '--pad-oper',
            \     '--add-braces',
            \     '--convert-tabs',
            \     '--align-pointer=name',
            \     '--break-return-type',
            \     '--attach-return-type-decl',
            \     '--pad-header',
            \     '--unpad-paren',
            \     '--max-code-length=120' ],
            \ }

when I use :Neoformat in normal mode (format the whole buffer), it works fine.

    if (t1 == 10)
        return 1;

formats to:

    if (t1 == 10) {
        return 1;
    }

But when I select some lines in visual mode and format (:'<,'>Neoformat), it works too, but don't use my format args.

the code mentioned above formats to:

if (t1 == 10)
{
    return 1;
}