Color class

An immutable color value in ARGB format.

Consider the light teal of the Flutter logo. It is fully opaque, with a red r channel value of 0.2588 (or 0x42 or 66 as an 8-bit value), a green g channel value of 0.6471 (or 0xA5 or 165 as an 8-bit value), and a blue b channel value of 0.9608 (or 0xF5 or 245 as an 8-bit value). In a common CSS hex color syntax for RGB color values, it would be described as #42A5F5.

Here are some ways it could be constructed:

const Color c1 = Color.from(alpha: 1.0, red: 0.2588, green: 0.6471, blue: 0.9608);
const Color c2 = Color(0xFF42A5F5);
const Color c3 = Color.fromARGB(0xFF, 0x42, 0xA5, 0xF5);
const Color c4 = Color.fromARGB(255, 66, 165, 245);
const Color c5 = Color.fromRGBO(66, 165, 245, 1.0);

If you are having a problem with Color.new wherein it seems your color is just not painting, check to make sure you are specifying the full 8 hexadecimal digits. If you only specify six, then the leading two digits are assumed to be zero, which means fully-transparent:

const Color c1 = Color(0xFFFFFF); // fully transparent white (invisible)
const Color c2 = Color(0xFFFFFFFF); // fully opaque white (visible)

// Or use double-based channel values:
const Color c3 = Color.from(alpha: 1.0, red: 1.0, green: 1.0, blue: 1.0);

Color's color components are stored as floating-point values. Care should be taken if one does not want the literal equality provided by operator==. To test equality inside of Flutter tests consider using isSameColorAs.

See also:

• Colors, which defines the colors found in the Material Design specification.
• isSameColorAs, a Matcher to handle floating-point deltas when checking Color equality.