media.php image interlace filter

[bobbravo2]

in wp-includes/media.php:448

imageinterlace($newimage, apply_filters('image_interlace',false);

See the pull request on github:
​https://github.com/bobbravo2/WordPress/pull/new/patch-1?quick_pull=1

[bobbravo2]

*Here is the public patch on github:*

Public ​https://github.com/bobbravo2/WordPress/commit/218d3ba7020854fe7daab7f3f8db8b1528d794e5

[markjaquith]

I think we should pass in $orig_type as a second parameter to the filter so that people can interlace only for certain image types.

Also, please space out your code a bit, like so:

imageinterlace( $newimage, apply_filters( 'image_interlace', false, $orig_type ) );

[bobbravo2]

Replying to markjaquith:

I think we should pass in $orig_type as a second parameter to the filter so that people can interlace only for certain image types.

Also, please space out your code a bit, like so:

imageinterlace( $newimage, apply_filters( 'image_interlace', false, $orig_type ) );

Done

[bobbravo2]

I can confirm that this filter works as intended for PNG, JPG, but NOT gif because "Underlying library (GD) does not support this feature."

To verify that the interlace bit has been set on JPG and PNG images, use ImageMagick

verify -verbose IMAGE_NAME.png/jpg

However, the filter does not cause any error on attempting to set the imageinterlace bit on a GIF

[nacin]

Would it make sense to perhaps pass $newimage by reference to an action, then any number of functions could be run on it? Or would that give unnecessary control?

[bobbravo2]

Replying to nacin:

Would it make sense to perhaps pass $newimage by reference to an action, then any number of functions could be run on it? Or would that give unnecessary control?

I think that's not necessary, as I see this filter as being defined once by a theme that heavily uses WordPress image_resize function. I think it may give too much control.

[SergeyBiryukov]

Version field indicates when the enhancement was initially suggested.

[bobbravo2]

Replying to SergeyBiryukov:

Version field indicates when the enhancement was initially suggested.

Thanks! I'm still learning my way around.

[bobbravo2]

Bump — any guidance on getting this added to the next release?

[SergeyBiryukov]

Related: #21668

[markoheijnen]

Duplicate of #21668.