Skip to main content

RAL colors and matching

RALColor represents a color from the RAL classic system. Internally it holds a RAL code and resolves it against a built-in lookup table that maps each code to a hex value.

Creating a RAL color​

use Renfordt\Colors\RALColor;

$ral = RALColor::create(3020);  // accepts int or numeric string
echo $ral->ral;  // 3020

The RAL code is stored as-is without range validation. Converting a code that is not present in the lookup table will fail when the table is accessed.

Converting from RAL​

RAL colors convert to hex through the lookup table, and to other formats through hex:

$ral = RALColor::create(3020);

$hex = $ral->toHex();  // HexColor
$rgb = $ral->toRGB();  // RGBColor
$hsl = $ral->toHSL();  // HSLColor
$hsv = $ral->toHSV();  // HSVColor

Finding the closest RAL color​

findClosestColor() takes a HexColor and returns the RALColor whose entry in the lookup table is nearest to it. Distance is the Euclidean distance between the two colors in RGB space:

$ral     = RALColor::create(3020);
$target  = HexColor::create('#FF5500');

$closest = $ral->findClosestColor($target);  // RALColor
echo $closest->ral;

The method compares the target against every entry in the table and returns the closest match. It returns null only if the lookup table is empty, which does not occur with the built-in table.