Free tool
Menu frame tester.
Drop in a frame image, set the slice and width, and see how 9-slice scaling wraps it around any page size without distorting the corners. New to 9-slice? Read the explainer. More free tools: the QR code generator and the menu contrast checker.
Frame asset
Expected source: 1200 x 1200 px
Slice and width
Distance from each edge of the source where the corners end. Same value on all four edges.
Rendered frame thickness on the page. Scale = frameWidth / frameSlice.
Page
Page size (px), synced with preview