[wp-trac] [WordPress Trac] #33642: Improve default Imagick compression settings

[WordPress Trac]

#33642: Improve default Imagick compression settings
-------------------------+------------------------
 Reporter:  joemcgill    |       Owner:  joemcgill
     Type:  enhancement  |      Status:  assigned
 Priority:  normal       |   Milestone:  4.5
Component:  Media        |     Version:
 Severity:  normal       |  Resolution:
 Keywords:  has-patch    |     Focuses:
-------------------------+------------------------

Comment (by joemcgill):

 [attachment:33642.4.patch] renames the `_resize()` method from
 [attachment:33642.3.patch] to `thumbnail_image()`.

 I've added feature detection for `getimagedepth()`, `setimagedepth()`,
 `setinterlacescheme()`, and `unsharpmaskimage()` to in the `test()` method
 and conditionally checks for the `getImageAlphaChannel()` Imagick method
 before applying it since it's not available on older versions ImageMagick
 and the functionality is not a requirement for the editor to work.

 This version no longer sets an sRGB colorspace, since retaining colors is
 one of the benefits of using ImageMagick over GD.

 I've limit to 8bits on resized files since this is only being applied to
 our resized images and seems to be the default way a few image editors
 (including Photoshop) handles optimizing images for web (even PNG24s).
 However, this version checks to see if the bit depth is greater than 8
 before applying the new bit depth so we don't add bits to a grayscale
 image that is only using 2–4 bits per channel.

 I've also added a new filter, `image_strip_meta` to override the stripping
 of image profiles and properties from resized images. This filter will
 only apply to sites using Imagick since GD always strips
 profiles/properties from images when resizing.

--
Ticket URL: <https://core.trac.wordpress.org/ticket/33642#comment:36>
WordPress Trac <https://core.trac.wordpress.org/>
WordPress publishing platform