images.UnsharpMask

The sigma argument is used in a gaussian function and affects the radius of effect. Sigma must be positive. The sharpen radius is approximately 3 times the sigma value.

The amount argument controls how much darker and how much lighter the edge borders become. Typically between 0.5 and 1.5.

The threshold argument controls the minimum brightness change that will be sharpened. Typically between 0 and 0.05.

Usage

Create the filter:

{{ $filter := images.UnsharpMask 10 0.4 0.03 }}

Apply the filter using the images.Filter function:

{{ with resources.Get "images/original.jpg" }}
  {{ with . | images.Filter $filter }}
    <img src="{{ .RelPermalink }}" width="{{ .Width }}" height="{{ .Height }}" alt="">
  {{ end }}
{{ end }}

You can also apply the filter using the Filter method on a Resource object:

{{ with resources.Get "images/original.jpg" }}
  {{ with .Filter $filter }}
    <img src="{{ .RelPermalink }}" width="{{ .Width }}" height="{{ .Height }}" alt="">
  {{ end }}
{{ end }}

Example

Original

Processed