Editor: incorrect poster dimensions being returned

[swissspidy]

Bug Description

Lucky found this obscure bug where the checklist in the editor shows a warning about incorrect poster dimensions, even though the poster definitely has the right size.

I tracked this down to some unexpected behavior in WordPress that boils down to honoring $content_width.

This only happens in the admin and not when accessing the REST API in an other way.

Here's how it works:

1. In the editor we preload REST API responses, such as the one for the current story (which is handled by Stories_Controller)
2. \Google\Web_Stories\REST_API\Stories_Controller::get_story_poster() calls wp_get_attachment_image_src()
3. wp_get_attachment_image_src() in turn calls image_downsize
4. image_downsize in turn calls image_constrain_size_for_editor
5. image_constrain_size_for_editor then reduces the width and height because we're in the admin (is_admin() is true because of the REST API preloading)

To work around this, I think we have to call image_get_intermediate_size() to get the actual size ourselves, and if that returns false (because the size does not exist), get the original size from wp_get_attachment_metadata().

But there might be other options.

Notes:

• This same issue theoretically exists in \Google\Web_Stories\Model\Story::load_from_post()
• We could just use the Story model in Stories_Controller, so we can delete the redundant get_story_poster method there

Aside:

I find it unexpected that wp_get_attachment_image_src() honors $content_width like this. Maybe worth opening a Trac ticket?

Expected Behaviour

There should be no incorrect warning.

Steps to Reproduce

1. Activate Twenty Twenty theme
2. Create a new story and add a few pages
3. Add a poster image by uploading a new image that needs to be cropped & crop it
4. Save the story
5. Reload the page
6. Notice the checklist warning about incorrect poster dimensions

Screenshots

Additional Context

• Plugin Version:
• WordPress Version:
• Operating System:
• Browser:

[spacedmonkey]

We have a filter in image_constrain_size_for_editor called editor_max_image_size. I wonder if this can be used the expected results.

Maybe worth opening a Trac ticket?

I think it is a good call.

[swissspidy]

Hmm I guess we could do something like this with that filter:

add_filter( 'editor_max_image_size', $constrain_dimensions );
$poster_src = wp_get_attachment_image_src( $thumbnail_id, Image_Sizes::POSTER_PORTRAIT_IMAGE_SIZE );
remove_filter( 'editor_max_image_size', $constrain_dimensions );

That seems to work

[spacedmonkey]

I am trying to think of a solution that would work with BC in mind. I was thinking about adding a filter before the preload and remove after preload is finished. Which might fix other issues in the future.

[swissspidy]

So basically doing that at a higher level (before the preload) vs. within the controller?

[spacedmonkey]

So basically doing that at a higher level (before the preload) vs. within the controller?

Yeah, I would have done it in edit-story.php.

[swissspidy]

I suppose that could work