shaderCallback property

Called to create the dart:ui.Shader that generates the mask.

The shader callback is called with the current size of the child so that it can customize the shader to the size and location of the child.

Typically this will use a LinearGradient, RadialGradient, or SweepGradient to create the dart:ui.Shader, though the dart:ui.ImageShader class could also be used.