Color class
An immutable 32 bit color value in ARGB format.
Consider the light teal of the Flutter logo. It is fully opaque, with a red
channel value of 0x42 (66), a green channel value of 0xA5 (165), and a blue
channel value of 0xF5 (245). In the common "hash syntax" for colour values,
it would be described as #42A5F5.
Here are some ways it could be constructed:
Color c = const Color(0xFF42A5F5);
Color c = const Color.fromARGB(0xFF, 0x42, 0xA5, 0xF5);
Color c = const Color.fromARGB(255, 66, 165, 245);
Color c = const Color.fromRGBO(66, 165, 245, 1.0);
If you are having a problem with Color 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:
Color c1 = const Color(0xFFFFFF); // fully transparent white (invisible)
Color c2 = const Color(0xFFFFFFFF); // fully opaque white (visible)
See also:
- Colors, which defines the colors found in the Material Design specification.
- Implementers
Constructors
- Color(int value)
-
Construct a color from the lower 32 bits of an int. [...]
const
- Color.fromARGB(int a, int r, int g, int b)
-
Construct a color from the lower 8 bits of four integers. [...]
const
- Color.fromRGBO(int r, int g, int b, double opacity)
-
Create a color from red, green, blue, and opacity, similar to
rgba()in CSS. [...]const
Properties
- alpha → int
-
The alpha channel of this color in an 8 bit value. [...]
read-only
- blue → int
-
The blue channel of this color in an 8 bit value.
read-only
- green → int
-
The green channel of this color in an 8 bit value.
read-only
- hashCode → int
-
The hash code for this object. [...]
read-only, override
- opacity → double
-
The alpha channel of this color as a double. [...]
read-only
- red → int
-
The red channel of this color in an 8 bit value.
read-only
- value → int
-
A 32 bit value representing this color. [...]
final
- runtimeType → Type
-
A representation of the runtime type of the object.
read-only, inherited
Methods
-
computeLuminance(
) → double - Returns a brightness value between 0 for darkest and 1 for lightest. [...]
-
toString(
) → String -
Returns a string representation of this object.
override
-
withAlpha(
int a) → Color -
Returns a new color that matches this color with the alpha channel
replaced with
a(which ranges from 0 to 255). [...] -
withBlue(
int b) → Color -
Returns a new color that matches this color with the blue channel replaced
with
b(which ranges from 0 to 255). [...] -
withGreen(
int g) → Color -
Returns a new color that matches this color with the green channel
replaced with
g(which ranges from 0 to 255). [...] -
withOpacity(
double opacity) → Color -
Returns a new color that matches this color with the alpha channel
replaced with the given
opacity(which ranges from 0.0 to 1.0). [...] -
withRed(
int r) → Color -
Returns a new color that matches this color with the red channel replaced
with
r(which ranges from 0 to 255). [...] -
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a non-existent method or property is accessed. [...]
inherited
Operators
-
operator ==(
dynamic other) → bool -
The equality operator. [...]
override