A WordPress plugin to automatically save the dominant color and a color palette for an attachment image into post_meta.

Uses ksubileau/color-thief-php as it's core, and shares that project's requirements:

• PHP >= 7.2
• Fileinfo extension
• One or more PHP extensions for image processing:
  • GD >= 2.0
  • Imagick >= 2.0 (but >= 3.0 for CMYK images)
  • Gmagick >= 1.0

The dominant color and color palette is automatically saved on upload and edit to post meta.

The dominant color can be overridden in the media gallery with any color from the palette in the media gallery.

You need to then use our function get_color_data() to retrieve the "dominant_color_hex" or "dominant_color_rgb" meta key. hex returns a string, including the #, rgb returns an array with key 0 as red, 1 as green, and 2 as blue.

You can also use the meta keys "color_palette_rgb" and "color_palette_hex" to get an array of 8 colors that feature prominently in the image.

My fellow brits: This was originally called "Dominant Colour", but given that the world we code in uses color, it makes more sense.