Where is rebol fill-pen documented (to get glow effect on a round rectangle) ?

Question

There is some discussion here about fill-pen http://www.mail-archive.com/[email protected]/msg02019.html

But I can't see documentation about cubic, diamond, etc... effect for fill-pen in rebol's official doc ?

I'm trying to draw some round rectangle with glowing effect but don't really understand the parameters I'm playing with so I can't get exactly what I'd like (I'd like the glow effect starting from the center not from the dark left top corner):

view layout [
    box 278x185 effect [ ; default box face size is 100x100
      draw [
        anti-alias on
        ; information for the next draw element (not required)
        line-width 2.5 ; number of pixels in width of the border
        pen black      ; color of the edge of the next draw element

        ; fill pen is a little complex:
        ;fill-pen 10x10 0 90 0 1 1 0.0.0 255.0.0 255.0.255
        fill-pen radial 20x20 5 55 5 5 10 0.0.0 55.0.5 55.0.5

        ; the draw element
        box     ; another box drawn as an effect
          15     ; size of rounding in pixels
          0x0 ; upper left corner
          278x170 ; lower right corner
      ]
    ]
]

Answer 1

Finally I made it so not sure how I did manage to get :)

view banner: layout/size [
    ;layout (window client area) size is 278x170 at the end of the spec block
    at 0x0 ;put the banner on the top left corner
    box 278x170 effect [ ; default box face size is 100x100
      draw [
        anti-alias on
        ; information for the next draw element (not required)
        line-width 2.5 ; number of pixels in width of the border
        pen black      ; color of the edge of the next draw element

        ; fill pen is a little complex:
        ;fill-pen 10x10 0 90 0 1 1 0.0.0 255.0.0 255.0.255
        ;fill-pen radial 100x50 5 55 5 5 10 55.0.5 30.10.10 55.0.5
        ;fill-pen radial 100x50 5 55 5 10 10 55.0.5 30.10.10 71.0.6
        fill-pen radial 100x50 5 55 5 10 10 71.0.6 30.10.10 71.0.6

        ; the draw element
        box     ; another box drawn as an effect
          15     ; size of rounding in pixels
          0x0 ; upper left corner
          278x170 ; lower right corner
      ]
    ]
    pad 30x-150
    Text "Experiment" font [name: "Impact" size: 24 color: white]
    image http://www.rebol.com/graphics/reb-logo.gif
] 278x170