createShader method

@override Shader createShader(Rect bounds)

Creates a Shader (i.e. a Gradient) from this object.

Implementation

@override
Shader createShader(Rect bounds) {
  final bool isObjectBoundingBox =
      unitMode == GradientUnitMode.objectBoundingBox;

  Matrix4 m4transform = transform == null
      ? Matrix4.identity()
      : Matrix4.fromFloat64List(transform!);

  if (isObjectBoundingBox) {
    final Matrix4 scale =
        affineMatrix(bounds.width, 0.0, 0.0, bounds.height, 0.0, 0.0);
    final Matrix4 translate =
        affineMatrix(1.0, 0.0, 0.0, 1.0, bounds.left, bounds.top);
    m4transform = translate.multiplied(scale)..multiply(m4transform);
  }

  final Vector3 v3from = m4transform.transform3(
    Vector3(
      from.dx,
      from.dy,
      0.0,
    ),
  );
  final Vector3 v3to = m4transform.transform3(
    Vector3(
      to.dx,
      to.dy,
      0.0,
    ),
  );

  return Gradient.linear(
    Offset(v3from.x, v3from.y),
    Offset(v3to.x, v3to.y),
    colors!,
    offsets,
    spreadMethod,
  );
}