update draft

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John Bowdre 2024-02-18 21:28:07 -06:00
parent 36c0b53180
commit cf63314218
3 changed files with 74 additions and 11 deletions

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@ -1,5 +1,5 @@
---
title: "Dynamic Opengraph Images With Hugo"
title: "Dynamic OpenGraph Images With Hugo"
date: 2024-02-18
# lastmod: 2024-02-18
draft: true
@ -7,7 +7,7 @@ description: "This is a new post about..."
featured: false
toc: true
comments: true
thumbnail: thumbnail.png
thumbnail: hugo-logo-wide.png
categories: Backstage
tags:
- hugo
@ -144,19 +144,34 @@ If it's the homepage, I'll set `$text` to hold the site description:
```jinja-html
{{- if .IsHome }}
{{ $text = .Site.Params.Description }}
{{ $text = .Site.Params.Description }}
{{- end }}
```
{{- if .IsPage }}
{{ $text = .Page.Title }}
{{ end }}
If it's a standard post page, then I want to use the page title instead:
```jinja-html
{{- if .IsPage }}
{{ $text = .Page.Title }}
{{ end }}
```
Now we get to some more interesting stuff. If the page has a `thumbnail` defined in the front matter, I'll use `$.Resources.Get` to grab the image. Note that the [`resources.Get` function](https://gohugo.io/functions/resources/get/) I used earlier works on global resources, like the image and font I had stashed in the sites `assets/` directory. The [`Resources.Get` method](https://gohugo.io/methods/page/resources/) is used for loading page resources, like the file indicated by the page's `thumbnail` parameter. Since I'm calling this method from within a `with` branch I have to put a `$` in front since the `.` would otherwise refer directly to the `thumbnail` parameter (which isn't a page and so doesn't have the method available). Hugo scoping is kind of wild.
Anyhoo, once I've got the thumbnail I use the [`Fit` image processing](https://gohugo.io/content-management/image-processing/#fit) to scale down the thumbnail (while preserving the aspect ration) and then the [`images.Overlay` function](https://gohugo.io/functions/images/overlay/) to stick it at the top right corner of the `og_base.png` image.
```jinja-html
{{- with .Params.thumbnail }}
{{ $thumbnail := $.Resources.Get . }}
{{ with $thumbnail }}
{{ $img = $img.Filter (images.Overlay (.Process "fit 300x250") 875 38 )}}
{{ end }}{{ end }}
{{ $thumbnail := $.Resources.Get . }}
{{ with $thumbnail }}
{{ $img = $img.Filter (images.Overlay (.Process "fit 300x250") 875 38 )}}
{{ end }}
{{ end }}
```
Then I can apply the desired text:
```jinja-html
{{ $img = $img.Filter (images.Text $text (dict
"color" "#d8d8d8"
"size" 64
@ -166,6 +181,50 @@ If it's the homepage, I'll set `$text` to hold the site description:
"font" $font
))}}
{{ $img = resources.Copy (path.Join $.Page.RelPermalink "og.png") $img }}
```
### All together now
Now I just need to merge my code in with the existing `layouts/partials/opengraph.html`
```jinja-html
// torchlight! {"lineNumbers": true}
{{ $img := resources.Get "og_base.png" }} <!-- [tl! **:2] -->
{{ $font := resources.Get "/FiraMono-Regular.ttf" }}
{{ $text := "" }}
<meta property="og:title" content="{{ .Title }}" />
<meta property="og:description" content="{{ with .Description }}{{ . }}{{ else }}{{if .IsPage}}{{ .Summary }}{{ else }}{{ with .Site.Params.description }}{{ . }}{{ end }}{{ end }}{{ end }}" />
<meta property="og:type" content="{{ if .IsPage }}article{{ else }}website{{ end }}" />
<meta property="og:url" content="{{ .Permalink }}" />
<meta property="og:locale" content="{{ .Lang }}" />
{{- if .IsHome }} <!-- [tl! **:2] -->
{{ $text = .Site.Params.Description }}
{{- end }}
{{- if .IsPage }}
{{- $iso8601 := "2006-01-02T15:04:05-07:00" -}}
<meta property="article:section" content="{{ .Section }}" />
{{ with .PublishDate }}<meta property="article:published_time" {{ .Format $iso8601 | printf "content=%q" | safeHTMLAttr }} />{{ end }}
{{ with .Lastmod }}<meta property="article:modified_time" {{ .Format $iso8601 | printf "content=%q" | safeHTMLAttr }} />{{ end }}
{{ $text = .Page.Title }} <!-- [tl! ** ] -->
{{ end }}
{{- with .Params.thumbnail }} <!-- [tl! **:start] -->
{{ $thumbnail := $.Resources.Get . }}
{{ with $thumbnail }}
{{ $img = $img.Filter (images.Overlay (.Process "fit 300x250") 875 38 )}}
{{ end }}
{{ end }}
{{ $img = $img.Filter (images.Text $text (dict
"color" "#d8d8d8"
"size" 64
"linespacing" 2
"x" 40
"y" 300
"font" $font
))}}
{{ $img = resources.Copy (path.Join $.Page.RelPermalink "og.png") $img }} <!-- [tl! **:end] -->
<meta property="og:image" content="{{$img.Permalink}}">
<meta property="og:image:width" content="{{$img.Width}}" />
@ -181,3 +240,7 @@ If it's the homepage, I'll set `$text` to hold the site description:
<meta property="og:video" content="{{ . | absURL }}" />
{{ end }}{{ end }}
```
And it works!
![Black background with text "Dynamic Opengraph Images With Hugo", a command prompt "[runtimeterror.dev] $", and colorful hexagon shapes with "HUGO" letters.](og-demo.png)

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