Introduces the Crop method for image processing which implements gift.CropToSize. Also allows a smartCrop without resizing, and updates the documentation.
Fixes#9499
In Hugo 0.90.0 we introduced remote support in `resources.Get`.
But with remote resources comes with a higher chance of failing a build (network issues, remote server down etc.).
Before this commit we always failed the build on any unexpected error.
This commit allows the user to check for any error (and potentially fall back to a default local resource):
```htmlbars
{{ $result := resources.Get "https://gohugo.io/img/hugo-logo.png" }}
{{ with $result }}
{{ if .Err }}
{{/* log the error, insert a default image etc. *}}
{{ else }}
<img src="{{ .RelPermalink }}" width="{{ .Width }}" height="{{ .Height }}" alt="">
{{ end }}
{{ end }}
```
Note that the default behaviour is still to fail the build, but we will delay that error until you start using the `Resource`.
Fixes#9529
This allows for constructs ala:
```
{{ $overlay := $img.Filter (images.Overlay $logo 50 50 )}}
```
Or:
```
{{ $logoFilter := (images.Overlay $logo 50 50 ) }}
{{ $overlay := $img | images.Filter $logoFilter }}
```
Which will overlay the logo in the top left corner (x=50, y=50) of `$img`.
Fixes#8057Fixes#4595
Updates #6731
This commit pulls most of the image related logic into its own package, to make it easier to reason about and extend.
This is also a rewrite of the transformation logic used in Hugo Pipes, mostly to allow constructs like the one below:
{{ ($myimg | fingerprint ).Width }}
Fixes#5903Fixes#6234Fixes#6266
The main motivation of this commit is to add a `page.Page` interface to replace the very file-oriented `hugolib.Page` struct.
This is all a preparation step for issue #5074, "pages from other data sources".
But this also fixes a set of annoying limitations, especially related to custom output formats, and shortcodes.
Most notable changes:
* The inner content of shortcodes using the `{{%` as the outer-most delimiter will now be sent to the content renderer, e.g. Blackfriday.
This means that any markdown will partake in the global ToC and footnote context etc.
* The Custom Output formats are now "fully virtualized". This removes many of the current limitations.
* The taxonomy list type now has a reference to the `Page` object.
This improves the taxonomy template `.Title` situation and make common template constructs much simpler.
See #5074Fixes#5763Fixes#5758Fixes#5090Fixes#5204Fixes#4695Fixes#5607Fixes#5707Fixes#5719Fixes#3113Fixes#5706Fixes#5767Fixes#5723Fixes#5769Fixes#5770Fixes#5771Fixes#5759Fixes#5776Fixes#5777Fixes#5778
