Adds a translucent 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_set_source_rgba().
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.
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_STATUS_PATTERN_TYPE_MISMATCH.
Adds a translucent 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_set_source_rgba(). 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. 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_STATUS_PATTERN_TYPE_MISMATCH.