Color.fromRGBO constructor Null safety
Create a color from red, green, blue, and opacity, similar to rgba()
in CSS.
r
is red, from 0 to 255.g
is green, from 0 to 255.b
is blue, from 0 to 255.opacity
is alpha channel of this color as a double, with 0.0 being transparent and 1.0 being fully opaque.
Out of range values are brought into range using modulo 255.
See also fromARGB, which takes the opacity as an integer value.
Implementation
const Color.fromRGBO(int r, int g, int b, double opacity) :
value = ((((opacity * 0xff ~/ 1) & 0xff) << 24) |
((r & 0xff) << 16) |
((g & 0xff) << 8) |
((b & 0xff) << 0)) & 0xFFFFFFFF;