Scales

`Scale.alpha_continuous`

using Gadfly
set_default_plot_size(21cm, 8cm)
palettef = Scale.lab_gradient("darkgreen", "orange", "blue")
p1 = plot(x=1:10, y=rand(10), color=1:10, Geom.point,
    Scale.color_continuous(colormap=palettef, minvalue=0, maxvalue=10),
    Guide.title("Scale.color_continuous, Theme(alphas=[0.5])"),
    Theme(alphas=[0.5], continuous_highlight_color=identity,
        point_size=2mm)
)
p2 = plot(x=1:10, y=rand(10), alpha=1:10, Geom.point,
    Scale.alpha_continuous(minvalue=0, maxvalue=10),
    Guide.title("Scale.alpha_continuous, Theme(default_color=\"blue\")"),
    Theme(default_color="blue", discrete_highlight_color=c->"gray",
        point_size=2mm)
)
hstack(p1, p2)

`Scale.alpha_discrete`

using DataFrames, Gadfly
set_default_plot_size(21cm, 8cm)
D = DataFrame(x=1:6, y=rand(6), Shape=repeat(["a","b","c"], outer=2))
coord = Coord.cartesian(xmin=0, xmax=7, ymin=0, ymax=1.0)
p1 = plot(D, x=:x, y=:y, color=:x,  coord,
    Scale.color_discrete, Geom.point, Geom.hair,
    Guide.title("Scale.color_discrete, Theme(alphas=[0.5])"),
    Theme(alphas=[0.5], discrete_highlight_color=identity,
        point_size=2mm)
)
p2 = plot(D, x=:x, y=:y, alpha=:x, shape=:Shape, coord,
    Scale.alpha_discrete, Geom.point, Geom.hair,
    Guide.title("Scale.alpha_discrete, Theme(default_color=\"green\")"),
    Theme(default_color="green", discrete_highlight_color=c->"gray",
        point_size=2mm, alphas=[0.0,0.2,0.4,0.6,0.8,1.0])
)
hstack(p1,p2)

`Scale.color_continuous`

using Gadfly
set_default_plot_size(21cm, 8cm)
xdata, ydata, cdata = rand(12), rand(12), rand(12)
p1 = plot(x=xdata, y=ydata, color=cdata)
p2 = plot(x=xdata, y=ydata, color=cdata,
          Scale.color_continuous(minvalue=-1, maxvalue=1))
hstack(p1,p2)