v150 · CSS · demo

Shape Explorer

Choose a polygon shape and adjust the corner radius. The round <length> parameter softens every vertex of a polygon() uniformly — watch the shape and the CSS update together.

Checking polygon() round support…
Shape
Corner radius
0px
Tightest effective radius 0px No clamping at this radius.

Without round

With round

round unit boundary

Polygon coordinates may be percentages, but the rounding slot itself is a CSS length. These probes run the exact clip-path: polygon() forms that separate the two.

clip-path: polygon(0% 0%, 100% 0%, 50% 100%) checking
clip-path: polygon(round 12px, 0% 0%, 100% 0%, 50% 100%) checking
clip-path: polygon(round 10%, 0% 0%, 100% 0%, 50% 100%) checking

Waiting for CSS parser results…

see also

implementation reference

Need the exact API surface, compatibility boundaries, errors, lifecycle, and source links? Read the matching gendn reference ↗