MetaShadowParams

struct MetaShadowParams {
  int radius;
  int top_fade;
  int x_offset;
  int y_offset;
  guint8 opacity;
}

The MetaShadowParams structure holds information about how to draw a particular style of shadow.

`radius`	The radius (gaussian standard deviation) of the shadow.
`top_fade`	If >= 0, the shadow doesn’t extend above the top of the shape, and fades out over the given number of pixels.
`x_offset`	Horizontal offset of the shadow with respect to the shape being shadowed, in pixels.
`y_offset`	Vertical offset of the shadow with respect to the shape being shadowed, in pixels.
`opacity`	Opacity of the shadow, from 0 to 255