# rgbToLab function Null safety

List<num> rgbToLab(
1. num r,
2. num g,
3. num b
)

Convert a RGB color to CIE-L*ab.

## Implementation

``````List<num> rgbToLab(num r, num g, num b) {
r = r / 255.0;
g = g / 255.0;
b = b / 255.0;

if (r > 0.04045) {
r = pow((r + 0.055) / 1.055, 2.4);
} else {
r = r / 12.92;
}
if (g > 0.04045) {
g = pow((g + 0.055) / 1.055, 2.4);
} else {
g = g / 12.92;
}
if (b > 0.04045) {
b = pow((b + 0.055) / 1.055, 2.4);
} else {
b = b / 12.92;
}

r = r * 100.0;
g = g * 100.0;
b = b * 100.0;

num x = r * 0.4124 + g * 0.3576 + b * 0.1805;
num y = r * 0.2126 + g * 0.7152 + b * 0.0722;
num z = r * 0.0193 + g * 0.1192 + b * 0.9505;

x = x / 95.047;
y = y / 100.0;
z = z / 108.883;

if (x > 0.008856) {
x = pow(x, 1 / 3.0);
} else {
x = (7.787 * x) + (16 / 116.0);
}
if (y > 0.008856) {
y = pow(y, 1 / 3.0);
} else {
y = (7.787 * y) + (16 / 116.0);
}
if (z > 0.008856) {
z = pow(z, 1 / 3.0);
} else {
z = (7.787 * z) + (16 / 116.0);
}

return [(116.0 * y) - 16, 500.0 * (x - y), 200.0 * (y - z)];
}``````