mehl.mx/themes/hugo-snap-gallery/README.md

# hugo-easy-gallery

**2019-01-20: I'm looking for people to help maintain this project - e.g. review and approve pull requests, which I no longer have time to do. Please contact me if you are interested. Thanks!**

Automagical css image gallery in [Hugo](https://gohugo.io/) using shortcodes, with optional lightbox/carousel gadget using [PhotoSwipe](http://photoswipe.com/) and jQuery.

**New:** Create a gallery of all images in a directory with just one line of shortcode, see [demo](https://www.liwen.id.au/heg/#gallery-usage).

**Need help?**
- Post your question at https://github.com/liwenyip/hugo-easy-gallery/issues.
- Include a link to a test page that demonstrates the issue you are having
- Include your source code for the test page
- Please be patient (I have a busy day job as that has nothing to do with web development or computer science, so every time I look at issues/PRs it takes me a while to get back up to speed); I will respond eventually. Please DO NOT email me asking for help, you are very unlikely to get a response from me this way.

**Fixed an issue or made an improvement?**
- Please submit a pull request
- Include a link to a test page
- Include your source code for the test page
- Let me know if you are in Sydney and I will thank you with beer :-)

## Demo

- Feature demonstration at https://www.liwen.id.au/heg/
- Real-life example at https://www.liwen.id.au/arduino-rf-codes/

## Image Gallery Features

- Custom `{{< figure >}}` shortcode that enables new features but is backwards-compatible with Hugo's built-in `{{< figure >}}`shortcode
- Use the `{{< figure >}}` shortcode by itself to enable pretty captions
- Put multiple `{{< figure >}}` shortcodes inside a `{{< gallery >}}` to create a pretty image gallery
- **Point `{{< gallery >}}` at a directory to generate a gallery of all images in that directory**
- Gallery is responsive, images are scaled/cropped to fill square (or other evenly-sized) tiles
- Pretty captions appear/slide/fade upon hovering over the image 
- Optionally make gallery images zoom, grow, shrink, slide up, or slide down upon hover
- Only requires 3.6kB of CSS (unminified; you can minify it if you want)
- CSS is automatically loaded the first time you use the `{{< figure >}}` shortcode on each page

## PhotoSwipe Features

- Load PhotoSwipe by calling the `{{< load-photoswipe >}}` shortcode anywhere in your post
- Loads all of the `<figure>` elements in your post, regardless of where in your post they appear, into a lightbox/carousel style image gallery
- Works with any existing `<figure>` elements/shortcodes in your posts
- Does not require you to [pre-define the image sizes](http://photoswipe.com/documentation/faq.html#image-size) (the initialisation script pre-loads the image to determine its size; you can optionally pre-define the image size if you want to avoid this pre-loading)
- Loads PhotoSwipe js and css libraries from `cdnjs.cloudflare.com`

## Installation
Put files in following places:

- /layouts/shortcodes/figure.html
- /layouts/shortcodes/gallery.html
- /layouts/shortcodes/load-photoswipe.html
- /static/js/load-photoswipe.js
- /static/css/hugo-easy-gallery.css

**NB `load-photoswipe.html` loads jQuery from `cdnjs.cloudflare.com`.**

- If your template already loads jQuery in the header, you can delete the jQuery link in `load-photoswipe.html`.
- If your template already loads jQuery in the footer,  you should `load-photoswipe.js` from the footer instead of in `load-photoswipe.html`.

If you want, you could (depending on a front matter param) conditionally load `load-photoswipe.html` or its contents from the footer of your template.  But I've consciously chosen to load PhotoSwipe using a shortcode so that you don't have to modify your template if you don't want to.

## Theme integration

Put files in the relevant folders within your theme.

Delete `/layouts/shortcodes/load-photoswipe.html`.

Rename `/layouts/shortcodes/load-photoswipe-theme.html` to `/layouts/shortcodes/load-photoswipe.html`.

Add the following lines to the footer of your template, just before `</body>`:

(Omit the jQuery line if jQuery is already loaded elsewhere in your template; just make sure that jQuery is loaded **before** this code.)

```html
<!-- Load PhotoSwipe js if the load-photoswipe shortcode has been used -->
{{ if ($.Scratch.Get "photoswipeloaded") }}
<script src="https://code.jquery.com/jquery-1.12.4.min.js" integrity="sha256-ZosEbRLbNQzLpnKIkEdrPv7lOy9C27hHQ+Xp8a4MxAQ=" crossorigin="anonymous"></script>
<script src="/js/load-photoswipe.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/photoswipe/4.1.1/photoswipe.min.js" integrity="sha256-UplRCs9v4KXVJvVY+p+RSo5Q4ilAUXh7kpjyIP5odyc=" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/photoswipe/4.1.1/photoswipe-ui-default.min.js" integrity="sha256-PWHOlUzc96pMc8ThwRIXPn8yH4NOLu42RQ0b9SpnpFk=" crossorigin="anonymous"></script>
{{ end }}
```

## `{{< figure >}}` shortcode usage

Specifying your image files:

- `{{< figure src="thumb.jpg" link="image.jpg" >}}` will use `thumb.jpg` for thumbnail and `image.jpg` for lightbox
- `{{< figure src="image.jpg" >}}` or `{{< figure link="image.jpg" >}}` will use `image.jpg` for both thumbnail and lightbox
- `{{< figure link="image.jpg" thumb="-small" >}}` will use `image-small.jpg` for thumbnail and `image.jpg` for lightbox

Optional parameters:

- All the [features/parameters](https://gohugo.io/extras/shortcodes) of Hugo's built-in `figure` shortcode work as normal, i.e. src, link, title, caption, class, attr (attribution), attrlink, alt
- `size` (e.g. `size="1024x768"`) pre-defines the image size for PhotoSwipe. Use this option if you don't want to pre-load the linked image to determine its size.
- `class` allows you to set any custom classes you want on the `<figure>` tag.

Optional parameters for standalone `{{< figure >}}` shortcodes only (i.e. don't use on `{{< figure >}}` inside `{{< gallery >}}` - strange things may happen if you do): 

- `caption-position` and `caption-effect` work the same as for the `{{< gallery >}}` shortcode (see below). 
- `width` defines the [`max-width`](https://www.w3schools.com/cssref/pr_dim_max-width.asp) of the image displayed on the page. If using a thumbnail for a standalone figure, set this equal to your thumbnail's native width to make the captions behave properly (or feel free to come up with a better solution and submit a pull request :-)). Also use this option if you don't have a thumbnail and you don't want the hi-res image to take up the entire width of the screen/container. 
- `class="no-photoswipe"` prevents a `<figure>` from being loaded into PhotoSwipe. If you click on the figure you'll instead a good ol' fashioned hyperlink to a bigger image (or - if you haven't specified a bigger image - the same one).

## `{{< gallery >}}` shortcode usage

To specify a directory of image files:

```
{{< gallery dir="/img/your-directory-of-images/" />}}`
```

- The images are automatically captioned with the file name.
- `[image].jpg` is used for the hi-res image, and `[image]-thumb.jpg` is used for the thumbnails.
- If `[image]-thumb.jpg` doesn't exist, then `[image].jpg` will be used for both hi-res and thumbnail images.
- The default thumbnail suffix is `-thumb`, but you can specify a different one e.g. `thumb="-small"` or `thumb="_150x150"`.

To specify individual image files:

```
{{< gallery >}}
  {{< figure src="image1.jpg" >}}
  {{< figure src="image2.jpg" >}}
  {{< figure src="image3.jpg" >}}
{{< /gallery >}}
```

Optional parameters:

- `caption-position` - determines the captions' position over the image. Options:
  - `bottom` (default)
  - `center`
  - `none` hides captions on the page (they will only show in PhotoSwipe)
- `caption-effect` - determines if/how captions appear upon hover. Options:
  - `slide` (default)
  - `fade`
  - `none` (captions always visible)
- `hover-effect` - determines if/how images change upon hover. Options:
  - `zoom` (default)
  - `grow`
  - `shrink`
  - `slideup`
  - `slidedown`
  - `none`
- `hover-transition` - determines if/how images change upon hover. Options:
  - not set - smooth transition (default)
  - `none` - hard transition

## PhotoSwipe usage

- Call `{{< load-photoswipe >}}` **once** on each page where you want to use PhotoSwipe.
- It doesn't matter where on the page.
- If you don't load PhotoSwipe, each figure will instead have a good ol' fashioned hyperlink to a bigger image (or - if you haven't specified a bigger image - the same one).

You can optionally have different captions on page vs in PhotoSwipe:

- `{{< figure src="image.jpg" alt="This is a caption">}}` or `{{< figure src="image.jpg" caption="This is a caption">}}` will use the same caption both on the page and in PhotoSwipe.
- `{{< figure src="image.jpg" caption="A short caption" alt="This is a much longer, verbose, comprehensive caption that will be used in PhotoSwipe">}}` will use a different caption in PhotoSwipe.

## CSS Hackers

`hugo-easy-gallery.css` is designed to provide square tiles in a container with `max-width: 768px`.

Here are some pointers if you want to adapt the CSS:

 - Change `.gallery {max-width: 768px;}` if you want a gallery wider than 768px.
 - Change `min-width` in the `@media` styles to change the screen widths at which the layout changes
 - Change `min-width: 9999px` in the last `@media` style to something sensible if you want to use a 4-tile layout
 - If you want more than 4 tiles per row, set `width` = 100% / number of tiles per row
 - `padding-bottom` = `width` gives square tiles. Change padding-bottom if you want some other aspect ratio, e.g. `width: 33.3%; padding-bottom: 25%` gives a 4:3 aspect ratio.

## Issues

I've tested this with the [beautifulhugo](https://github.com/halogenica/beautifulhugo) theme. If things don't work properly with other themes, raise an issue on GitHub, or even better fix the issue and submit a pull request :-)

## Credits

These blog posts helped me immensely:

- http://www.dwuser.com/education/content/creating-responsive-tiled-layout-with-pure-css/
- http://www.thehome.dk/article/photoswipe-gallery-hugo/
- https://webdesign.tutsplus.com/tutorials/the-perfect-lightbox-using-photoswipe-with-jquery--cms-23587