Gradient.radial constructor
Creates a radial gradient centered at center
that ends at radius
distance from the center.
If colorStops
is provided, colorStops[i]
is a number from 0.0 to 1.0
that specifies where color[i]
begins in the gradient. If colorStops
is
not provided, then only two stops, at 0.0 and 1.0, are implied (and
color
must therefore only have two entries).
The behavior before and after the radius is described by the tileMode
argument. For details, see the TileMode enum.
If center
, radius
, colors
, or tileMode
are null, or if colors
or
colorStops
contain null values, this constructor will throw a
NoSuchMethodError.
If matrix4
is provided, the gradient fill will be transformed by the
specified 4x4 matrix relative to the local coordinate system. matrix4
must
be a column-major matrix packed into a list of 16 values.
Implementation
Gradient.radial(
Offset center,
double radius,
List<Color> colors, [
List<double> colorStops,
TileMode tileMode = TileMode.clamp,
Float64List matrix4
]) : assert(_offsetIsValid(center)),
assert(colors != null),
assert(tileMode != null),
super._() {
if (matrix4 != null && matrix4.length != 16)
throw new ArgumentError('"matrix4" must have 16 entries.');
_validateColorStops(colors, colorStops);
final Int32List colorsBuffer = _encodeColorList(colors);
final Float32List colorStopsBuffer = colorStops == null ? null : new Float32List.fromList(colorStops);
_constructor();
_initRadial(center.dx, center.dy, radius, colorsBuffer, colorStopsBuffer, tileMode.index, matrix4);
}