Same name and namespace in other branches

1. 4.0.x modules/field_example/src/Plugin/Field/FieldFormatter/ColorBackgroudFormatter.php \Drupal\field_example\Plugin\Field\FieldFormatter\ColorBackgroudFormatter::lightness()

Determine lightness of a color.

This might not be the best way to determine if the contrast between the foreground and background colors is legible. But it'll work well enough for this demonstration.

Logic from https://stackoverflow.com/a/12228730/8616016.

Parameters

string $color: A color in hex format, leading '#' is optional.

Return value

float Percentage of lightness of the provided color.

1 call to ColorBackgroudFormatter::lightness()

ColorBackgroudFormatter::viewElements in modules/field_example/src/Plugin/Field/FieldFormatter/ColorBackgroudFormatter.php

Builds a renderable array for a field value.

File

modules/field_example/src/Plugin/Field/FieldFormatter/ColorBackgroudFormatter.php, line 129

Class

ColorBackgroudFormatter

Plugin implementation of the 'field_example_color_background' formatter.

Namespace

Drupal\field_example\Plugin\Field\FieldFormatter

Code

protected function lightness(string $color) {
    $hex = ltrim($color, '#');
    // Convert the hex string to RGB.
    $r = hexdec($hex[0] . $hex[1]);
    $g = hexdec($hex[2] . $hex[3]);
    $b = hexdec($hex[4] . $hex[5]);
    // Calculate the HSL lightness value and return that as a percent.
    return (max($r, $g, $b) + min($r, $g, $b)) / 510.0 * 100;
}