Add a rounded box path at position (x, y) with size (w, h) and a separate
radius for each corner listed in clockwise order, so that cr0 = top left,
cr1 = top right, cr2 = bottom right, cr3 = bottom left;
this is a low level drawing function: the path must be stroked or filled
to become visible.
The D Programming Language's Unofficial Docs
beta
Add a rounded box path at position (x, y) with size (w, h) and a separate radius for each corner listed in clockwise order, so that cr0 = top left, cr1 = top right, cr2 = bottom right, cr3 = bottom left;
this is a low level drawing function: the path must be stroked or filled to become visible.