[wp-trac] [WordPress Trac] #55036: Sharpen thumbnails with Imagick adaptiveSharpenImage()
WordPress Trac
noreply at wordpress.org
Wed Feb 2 04:58:14 UTC 2022
#55036: Sharpen thumbnails with Imagick adaptiveSharpenImage()
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Reporter: galbaras | Owner: (none)
Type: enhancement | Status: new
Priority: normal | Milestone: Awaiting Review
Component: Media | Version: 5.9
Severity: normal | Keywords:
Focuses: |
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The Imagick function `resizeImage()` often produces thumbnails with a low
visual quality (blurry/grainy). The world is moving to small high-
resolution devices, where visual quality makes a difference, and we need
something better.
Fortunately, `adaptiveSharpenImage()` (see
https://www.php.net/manual/en/imagick.adaptivesharpenimage.php) sharpens
the subject/foreground of the image, while not sharpening the background
(as much).
I've tested it with various `sigma` values, and `1` got me a nice enough
result (`radius` was `0` == auto). However, it would be good to test
ranges of image sizes and ranges of scaling ratios (original size /
thumbnail size) to find out more.
For even more flexibility, there should be filters on the default values
of `radius` and `sigma`. This will allow developers to have finer control
on specific sites that need a bit more.
Alternatively, `add_media_size()` can be extended to accept `radius` and
`sigma`, which can then be used during thumbnail generation. This will
also be a convenient way for developers to update the sharpening settings
of existing media sizes.
Option: when Imagick is used, add `radius` and `sigma` fields to the
definition of image sizes in Settings > Media -OR- in the customizer for
site-specific control without coding.
See also: #40415
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Ticket URL: <https://core.trac.wordpress.org/ticket/55036>
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