add dithering example

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David Eisinger
2024-02-12 17:15:43 -05:00
parent 4012b4dc03
commit 0669cd273b
5 changed files with 42 additions and 5 deletions

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@@ -46,7 +46,14 @@ Most of what I post on this site are these monthly [dispatches][6] that start wi
I tried treating the full-size images with ImageMagick on the command line and then letting Hugo resize the result, but I wasn't happy with the output -- there's still way too much data in a dithered full-sized image, so when you scale it down, it just looks like a crappy black-and-white photo. Furthermore, the encoding wasn't properly optimizing for two-color images and so the files were larger than I wanted.
I needed to find some way to scale the images to the appropriate size and _then_ apply the dither. Fortunately, Hugo has the ability to [fetch remote images][9], which got me thinking about a separate image processing service. After a late night of coding, I've got a solution I'm quite pleased with. Read on for more details, and if you want to follow along, you'll need to have Ruby installed (I recommend [asdf][10] if you're on a Unix-y OS) as well as ImageMagick and OpenSSL.
I needed to find some way to scale the images to the appropriate size and _then_ apply the dither. Fortunately, Hugo has the ability to [fetch remote images][9], which got me thinking about a separate image processing service. After a late night of coding, I've got a solution I'm quite pleased with.
Here's a picture of me, before and after dithering:
{{<thumbnail race_121539.jpg "782x900" />}}
{{<dither race_121539.jpg "782x900" />}}
Read on for more details, and if you want to follow along, you'll need to have Ruby installed (I recommend [asdf][10] if you're on a Unix-y OS) as well as ImageMagick and OpenSSL.
[9]: https://gohugo.io/content-management/image-processing/#remote-resource
[10]: https://asdf-vm.com/
@@ -86,7 +93,7 @@ end
### 2. Build a tiny image server
I wrote a [very simple image server][13] using [Sinatra][14] and [MiniMagick][15] that takes a path to an image and an optional geometry string and returns a dithered image. I won't paste the entire file here but it's really pretty short and simple.
I made a [standalone image server][13] using [Sinatra][14] and [MiniMagick][15] that takes a path to an encrypted image and an optional geometry string and returns a dithered image. I won't paste the entire file here but it's really pretty short and simple.
[13]: https://github.com/dce/davideisinger.com/blob/bf5238dd56b6dfe9ee2f1d629d017b2075750663/bin/dither/dither.rb
[14]: https://sinatrarb.com/
@@ -112,9 +119,8 @@ Then, assuming you have an encrypted image at `content/path/to/file.jpg.enc`, yo
We need to tell Hugo where to find our image server, which we'll supply with an environment variable. First, we'll give Hugo access to `DITHER_SERVER` in `config.toml`:
```toml
[security]
[security.funcs]
getenv = ['DITHER_SERVER']
[security.funcs]
getenv = ['DITHER_SERVER']
```
Then start Hugo like this:

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