Custom Image Sizes/How does picturefill_wp_add_image_size() really work?

Reporting back. Upon inspecting the code further I pulled up the plugins functions. This is what I saw.

function picturefill_wp_add_image_size($name, $width = 0, $height = 0, $crop = false, $insert_before = 'thumbnail'){
  if('@2x' === substr($name, -3)){
    return false;
  }
  add_image_size($name, $width, $height, $crop);
  add_image_size($name . '@2x', $width * 2, $height * 2, $crop);

  $picturefill_wp_helpers = new Picturefill_WP_Function_Helpers();
  $picturefill_wp_helpers->add_image_to_responsive_queue($image_size, $insert_before);
}

First off – this confirms that we don’t need to use the built in add_image_size function as picturefill_wp_add_image_size will pass that info on nicely for us. A concern here would be if a user had defined custom sizes with this code and then disabled the plugin for whatever reason then add_image_size would not be run – but perhaps that will be considered for the next revision.

With that in mind – the documentation needs edited here:

$image_size_array = array('custom_small_size', 'thumbnail', 'extra-large');
/* All image sizes included in the $image_size_array
   must allready exist, either by default (thumbnail,
   medium, and large) or by the add_image_size function.
   Image sizes should be listed from smallest to largest
   and should not include '@2x' sizes, these will be
   added automatically. */
picturefill_wp_set_responsive_image_sizes($image_size_array);

Particularly the part that says “… or by the add_image_size function”. To clear up any confusion this should read “… or by the picturefill_wp_add_image_size function”.

Let’s move on. The line in particular in question is lines 43-44 in functions-picturefill-wp.php

$picturefill_wp_helpers = new Picturefill_WP_Function_Helpers();
$picturefill_wp_helpers->add_image_to_responsive_queue($image_size, $insert_before);

As we can see “$image_size” is being asked for by this function, but not provided anywhere. I assumed this meant I could interchange it for $name, since that seemed to be the authors intent with the variable, but was once again met with page hangs and endless loading.

Is this a bug or is $image_size intentional? I’m trying to figure out more but if the author is around your input would be excellent! ??

-Zach

Hi Zack, thanks very much for the thoughtful feedback. You are touching on a few of the more difficult design challenges that have come up with this plugin.

First, you are absolutely right about the misnamed attribute in the add_image_to_responsive_queue method on line 44 of functions-picturefill-wp.php. This issue was also brought up by hguiney on GitHub and should be corrected in the latest version 1.3.4.

One of the biggest challenges with a plugin like this is the user interface. I have decided to go in a different direction than many other similar plugins by not having an admin UI and keeping all of the configuration with code in the theme files. I believe this more closely reflects the WordPress philosophy by keeping design considerations segregated in the theme and left to the discretion of the theme designer/implementer. As you’ve struck on here, creating a flexible code based UI is challenging. I’m very often surprised by the use cases that come up. I’m dedicating most of my energy around this to Picturefill.WP 2, which is going to be a separate plugin using the new Picturefill 2.x syntax. I’m planning on maintaining both plugins, but updates to Picturefill.WP 1.3.x are going to be limited mostly to bug-fixes.

You have made good suggestions regarding documentation, and I will be sure to work those in as I re-evaluate the docs. Please continue to let me know when the documentation seems confusing or incomplete. It can be hard to read these things outside your own head, and external feedback is always welcome.

Thanks again very much for the detailed feedback.

Thanks for the quick response! Installing 1.3.4 now and excited to see how it runs. Glad you enjoy the feedback, it’s a truly powerful plugin that more people should really be learning. I am currently writing a blog post on the best way to optimize wordpress and will be featuring this plugin alongside some basic instructions for set up with bootstrap 3.

Some of my issues also may have come from using the upBootWP bootstrap 3 framework but a quick look over didn’t lead to anything sticking out as a problem. I’m setting up now and will let you know how it goes shortly.

Thanks again,

-Zach

Resolved.