| r | Rectangle determining the size of the graph. |
| eval | Normalized x-position in the range [0; 1] at which the curve should be evaluated. The returned value is expected to be in the range [0; 1] and a value of 0 corresponds to the vertical center of the rectangle that is drawn into. Values outside of this range will be clamped. |
Fills the area between the curve evaluated by the AudioCurveAndColorEvaluator provided and its vertical mirror image with smooth gradients along the edges. Useful for drawing amplitude plots of audio signals.