Vignette added

I've wanted to be able to add a vignette (a darkening of the corners and edges) to a fractal as is common in photo editing software, so finally I wrote one. It's Vignette in jlb.ucl.

It's a direct coloring, producing a layer with white at the center and grays to black at the edges. It is meant to be used as a top layer, with Multiply. Here are the parameters:

radius: inside this radius, there is no effect. Vignette uses screen-relative coordinates, from -1 to 1, so values can range from 0 to 2. (It's only a real radius if the shape is 2 and the fractal is square.)

shape: 2 makes a circular or elliptical shape. Higher values approach a square, 1 makes a diamond, lower values an astroid.

smoothness: 0 makes a sharp edge, higher values make a smooth transition.

brightness: 0 makes the corners black. A larger value makes the corners a shade of gray.

Here's an example with two vignette layers added:

VignetteExample {
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  szebVGp+QTV1rKX1z8oK7Y5Km8ud345pEKJPz/vEnq5KF3j/ErqVy99+moQdOLCh8OzFnOrM
  /Vyem31nFoRm3xLEq+M/PKq8er8C/N0bDw3SQE0b+Iri3PZkggfYs/ubMwNlNn1qEN1zKMx3
  rpllLUPnhhKVx7OxraK4ZVXkKRr8Zwk6cTx4zs+ezxvjV33y641qsn5gpKWbro+0QRAr8uM0
  tQ6YnqzI7upspDwzMurYPJ0+xhoEsHr4LX6NJxrUI51QHk5/JFrug1Vc4SZlvHkuunz8/TxT
  cJ0Ni6eRB/urHjSIX1N1cv+GpoILkEngTRwvd30cR5GrUUzZdLjmgjnV+vIf4wlc51KPNs81
  5p94jHnMYGZtHLPmLhBzhHPeiXz7E5O2zbkNdw8R7YIJf3XhojnrmHxC3zqFeJ0OWh4SfG6Q
  Cdm1+zsWeW4MLtNfTTHHoLhDD4vCW3dzJdigW1Mm6raagLga+orRxM3W2n4JqL4Pll6ZOmZo
  xnhp2SDBJmLAGb4o44YCmO6K0OWK1yQM67gTp0k4kgRPJh2FGRstg3u04AnoDR2WoRzwHSTA
  QRT+icbcHLpBbWfCyuVJY7TEhsd9JhO4dGek4otrfqd07TtP/7jj3s+7pJ2RTjstEsd/vnY3
  t7xO4xzhHEHCvSCvAPINN/mZdzIC0VhLYa8jF5wvKy9/fROHNugX14eVj7XdNu7BREu8B4es
  tGntg2KqX7RHwxR4EENIIkiQ04YaEmeL+AKhGiIppBajhRIoPNycJHCDRwFX67NXFZ1ng1Yx
  J0NU/IR00Xg63smZ494eFrTZEZbPO8KOx8/HYCJo7BFI5/sWZBHwBTL0hgXiuZVVJ1Icqzx4
  5+DDKifywefYUq5djid+6+w4Rr89biH1f9pWpt+VRr+DHez7IuWorgdR1YmYL77yLFng59B0
  IaQEecQVxkSdOywvfvedw8ZZI3JF5j5IvE+eTBMtGyywjPygsYidSv+dax05cm8h7me44QXP
  SYLQ48tCbvufxwB/4w06LHLD7a7tWOWOYZFFmbmTd8ExP2hA5aau7v/3P+5OW7nHd7vS0Odn
  t3rXqu2d2RAlTbrdekOh1espssnrQZrml2j/dfOTyRZ4Nhi3CK8SbOvtpXr4469J9R6PMvRs
  OcBTNO7Xx5gnw1ROcuIZoN7H80V71hGM1Sa6cim+pE48gd4PLnu0nVAbweLiyh8s8On7WFIe
  DgLZOLnOEnl/F8mlvF02qHpBWb1G5KptKwrcWpomJ/XTaLi2d/TLvu0mdEbwbLDzh4sdPn5W
  HKeLoL5ObvOkndALYPbnLov1PXD8369zVCcdoGG8nuLNFdd9FrF4cWxbz9pCsXeK0GMN2dbq
  RXR27hHbvcY62bSid2kFjDstQS2aPeszBFH5sI+PYRWYhDn1uTcWtOc7FpJ2NPJwxCFv9i0R
  BOrd7wjJbX/AkN+AnxHst52EP1O69hYnFpTdr/LaT6/BkodA7A==
}

The images below show the fractal before and after vignetting.

Looks interesting, Jim. Many thanks for this.

Looks great, thanks for posting about it here!

I used it on this image on Deviant Art:
https://www.deviantart.com/velvet--glove/art/Nocturne-845015115

I find it quite handy having a vignette layer that auto-adjusts to whatever shape and size the image is rather than having to work out the x-y image ratio manually. Yes, I'm lazy like that.

Thanks again!

PS. I've tried twice to post that link but it doesn't seem to be clickable. Sorry.

The link worked now for me. Happy that this was useful.