Return a new Imlib2::Gradient.
Examples:
# create a blue to green gradient
grad = Imlib2::Gradient.new
grad.add_color 0, Imlib2::Color::BLUE
grad.add_color 100, Imlib2::Color::GREEN
# create a red to yellow to black gradient
colors = [ [0, Imlib2::Color::RED ],
[100, Imlib2::Color::YELLOW ],
[200, Imlib2::Color::BLACK ] ]
grad = Imlib2::Gradient.new *colors
Add a color at the given distance
Examples:
# add the context color with a 100 pixel offset
grad.add_color 100
# add white at a 100 pixel offset
grad.add_color 100, Imlib2::Color::WHITE