an offset in the range [0.0 .. 1.0]
red component of color
green component of color
blue component of color
Note: If the pattern is not a gradient pattern, (eg. a linear or radial pattern), then the pattern will be put into an error status with a status of cairo.types.Status.PatternTypeMismatch.
Adds an opaque color stop to a gradient pattern. The offset specifies the location along the gradient's control vector. For example, a linear gradient's control vector is from (x0,y0) to (x1,y1) while a radial gradient's control vector is from any point on the start circle to the corresponding point on the end circle.
The color is specified in the same way as in cairo.context.Context.setSourceRgb.
If two (or more) stops are specified with identical offset values, they will be sorted according to the order in which the stops are added, (stops added earlier will compare less than stops added later). This can be useful for reliably making sharp color transitions instead of the typical blend.