button class tc-btn-rounded for button widget

[A Gloom]

I didn't see 'tc-btn-rounded' listed along with

Tip: Set class to tc-btn-invisible tc-tiddlylink to have a button look like an internal link.

works with images such as TW core svg's

<$button class='tc-btn-rounded' style="margin:2px 0px; padding:5px; border:solid 2px;"><$action-navigate $to="#Create new bookmark"/> {{$:/core/ui/Buttons/new-tiddler}}</$button>

recreates the new tiddler button (with the + icon) found above the search bar but with your own button action

also works with text to create circle or oval buttons:

<$button class='tc-btn-rounded' style="margin:2px 0px; padding:5px; border:solid 2px;"><$action-navigate $to="#Create new bookmark"/>555</$button>

creates an oval button labeled 555

the dimensions/shape of the circle/oval determined by:

a single character produces a circle

a single line of several characters produces an oval, width determined by length of word

additional lines of text would increase the height of the oval as would adfusting the padding of the style attribute

the circle/oval size/shape can also be fine tuned using padding-top, padding-bottom, padding-right, padding-left