Parses the input string for a gradient spread value, which indicates what happens if the gradient starts or ends inside the bounds of the target rectangle.
The allowable values are pad | reflect | repeat
Input string to parse
Default Value. If the string is empty, the default value is returned
If the string is empty, the default value (DefValue) is returned.
Possible values are: 'pad', which says to use the terminal colors of the gradient to fill the remainder of the target region, 'reflect', which says to reflect the gradient pattern start-to-end, end-to-start, start-to-end, etc. continuously until the target rectangle is filled, and repeat, which says to repeat the gradient pattern start-to-end, start-to-end, start- to-end, etc. continuously until the target region is filled.
If the attribute is not specified, the effect is as if a value of 'pad' were specified.