mirror of https://github.com/gohugoio/hugo
41 lines
1.0 KiB
Markdown
41 lines
1.0 KiB
Markdown
---
|
|
title: images.Sigmoid
|
|
description: Returns an image filter that changes the contrast of an image using a sigmoidal function.
|
|
categories: []
|
|
keywords: []
|
|
action:
|
|
aliases: []
|
|
related:
|
|
- functions/images/Filter
|
|
- methods/resource/Filter
|
|
returnType: images.filter
|
|
signatures: [images.Sigmoid MIDPOINT FACTOR]
|
|
toc: true
|
|
---
|
|
|
|
This is a non-linear contrast change useful for photo adjustments; it preserves highlight and shadow detail.
|
|
|
|
The midpoint is the midpoint of contrast. It must be in the range [0, 1], typically 0.5.
|
|
|
|
The factor indicates how much to increase or decrease the contrast, typically in the range [-10, 10] where 0 has no effect. A positive value increases contrast, while a negative value decrease contrast.
|
|
|
|
## Usage
|
|
|
|
Create the filter:
|
|
|
|
```go-html-template
|
|
{{ $filter := images.Sigmoid 0.6 -4 }}
|
|
```
|
|
|
|
{{% include "functions/images/_common/apply-image-filter.md" %}}
|
|
|
|
## Example
|
|
|
|
{{< img
|
|
src="images/examples/zion-national-park.jpg"
|
|
alt="Zion National Park"
|
|
filter="Sigmoid"
|
|
filterArgs="0.6,-4"
|
|
example=true
|
|
>}}
|