Setting default quality doesn't always work

[markoheijnen]

Due to a misplaced if statement in [28879] the quality doesn't get set for non JPG images.
Setting quality for Imagick also failed. Added unit tests to check for default behaviour.

[johnbillion]

Line 259 of class-wp-image-editor.php in 29856.diff​ is this:

if ( $quality == null ) {

Should that have a strict equality check?

[markoheijnen]

Yes, it does.

[SergeyBiryukov]

In 29834:

Fix setting default quality in WP_Image_Editor.

props markoheijnen.
fixes #29856 for trunk.

[ocean90]

#29903 was marked as a duplicate.

[tomauger]

This patch broke image multiresizing on a live multisite (that was accidentally using Trunk rather than stable ooops).

Essentially, using WP_Image_Editor_GD, setting quality on load() set the quality of all image sizes to 1.

It should also be noted that the direct call to set_quality() bypasses all the quality filters. I'm not sure whether this is an issue, but it threw me for a loop as I was trying to log the quality setting and the filters were just not being called at all.

Interestingly, I am not seeing the issue on a Vanilla install with Twentythirteen and no plugins. However, I did disable all plugins and used Twentyten on the multisite and the issue occurred consistently. A mirror dev site using the same database and configuration, but the stable 4.0 instead of trunk was not experiencing the issue.

[markoheijnen]

I'm unsure why this would fail for you. set_quality() would fallback to the property default_quality because the value passed is null. So the quality would be 90 then. I do see the issue of filters not getting passed.

[markoheijnen]

Move running filters to set_quality method.

[markoheijnen]

I added an additional patch that moves all the logic from get_quality() to set_quality(). This way the filters will run always.
So as a developer I expect that calling set_quality() will always go to the default value which I can filter with 'wp_editor_set_quality'.

[tomauger]

That's fantastic Marko - I'll test the patch and report back if there's anything weird, but I can't imagine there would be.

[samhotchkiss]

works for me

[tomauger]

Everything seems in order here.

[DrewAPicture]

@markoheijnen, @SergeyBiryukov: What's left here for 4.1? Is 29856.3.diff​ the agreed-upon solution?

[SergeyBiryukov]

In 30788:

Move the logic from WP_Image_Editor::get_quality() to WP_Image_Editor::set_quality(), so that 'wp_editor_set_quality' and 'jpeg_quality' filters run when setting the default value.

props markoheijnen.
fixes #29856.

[kirasong]

Tests and Docs to clarify filter precedence.

[kirasong]

Was going through the unit tests for this, and found several edge cases that needed a bit of further testing.

While doing so, noticed that it's not clear in docs that if you instantiate an editor, then either quality filter is applied, it does not affect the quality of any further images saved by that editor (unless set_quality is directly called with a null parameter).

Would be great to get the docs changes in 4.1 if it's still an option. Unit tests, of course, also help, but can wait if it's too much for the milestone.

The attached patch​ contains both changes, but I can split them out if it's helpful.

[markoheijnen]

The attached patch look good and is ready to go in. We could even explain more by mentioning that when set_quality is called with a null that it reverts back to the default value. Which is filterable.

[johnbillion]

In 30873:

Add tests which ensure the wp_editor_set_quality and jpeg_quality filters only apply if they are added before the corresponding WP_Image_Editor is instantiated.

Props DH-Shredder
See #29856

[johnbillion]

The inline docs for the wp_editor_set_quality and jpeg_quality filters still aren't great, but I can't come up with anything better.

[johnbillion]

In 30874:

Clarify the behaviour of the wp_editor_set_quality and jpeg_quality filters.

Props DH-Shredder
See #29856

[johnbillion]

In 30875:

Add tests which ensure the wp_editor_set_quality and jpeg_quality filters only apply if they are added before the corresponding WP_Image_Editor is instantiated.

Merges [30873] to the 4.1 branch.

Props DH-Shredder
See #29856

[johnbillion]

In 30876:

Clarify the behaviour of the wp_editor_set_quality and jpeg_quality filters.

Merges [30874] to the 4.1 branch.

Props DH-Shredder
See #29856