The gradient of the button’s border.
- macOS 10.0–10.12Deprecated
The value of this property is a constant that specifies the gradient used for the button's border. See
NSButton for a list of possible values.
If the button has no border, setting this property has no effect on the button’s appearance. A concave gradient is darkest in the top-left corner; a convex gradient is darkest in the bottom-right corner. Weak versus strong is how much contrast exists between the colors used in opposite corners.