与牛奶的颜色不透明度

Question

使用Gadfly绘图时是否可以控制alpha属性（不透明度或透明度）？我试图绘制分布的比较。任何信息将不胜感激。

Answer 1

尚未，但它是planned feature that seems close to being added。

Answer 2

Geom.ribbon是可能的。以下代码从nabble.com复制粘贴该图，并使用Geom.ribbon opacity问题on Github：

using Gadfly, DataFrames, Distributions
d1 = Normal(-1);
d2 = Normal(1);
x = -4:0.01:4
y1 = pdf(d1, x);
y2 = pdf(d2, x);
df1 = DataFrame(x = x, y = y1, ymin = 0.0, ymax = y1, d = "d1");
df2 = DataFrame(x = x, y = y2, ymin = 0.0, ymax = y2, d = "d2");
df = vcat(df1, df2)

# No transparency
p1 = plot(df, x = :x, y = :y, ymin = :ymin, ymax = :ymax, color = :d, Geom.line, Geom.ribbon)

# With transparency
p2 = plot(df, x = :x, y = :y, ymin = :ymin, ymax = :ymax, color = :d, Geom.line, Geom.ribbon),
          Theme(lowlight_color=c->RGBA{Float32}(c.r, c.g, c.b, 0.2)))

draw(PNG("test1.png", 12cm, 6cm), p1)
draw(PNG("test2.png", 12cm, 6cm), p2)

没有透明度的图

具有透明度的图