Creates a new radial gradient pattern between the two
circles defined by (c0, radius0) and (c1, radius1). Before
using the gradient pattern, a number of color stops should
be defined using Pattern.addColorStopRGB() or
Pattern.addColorStopRGBA().
Note: The coordinates here are in pattern space. For a new pattern,
pattern space is identical to user space, but the relationship
between the spaces can be changed with Pattern.setMatrix().
Creates a new radial gradient pattern between the two circles defined by (c0, radius0) and (c1, radius1). Before using the gradient pattern, a number of color stops should be defined using Pattern.addColorStopRGB() or Pattern.addColorStopRGBA().