How to place the colorkey legend inside the plot?

[montyvesselinov]

How to place the colorkey legend inside the plot? How to control colorkey legend location?

[darwindarak]

You can adjust the position of the colorkey by setting the key_position argument in the Theme object as :top, :bottom, :left, :right, or :none

plot(x=rand(12), y=rand(12), color=repeat(["a","b","c"], outer=[4], 
     Themes(key_position = :bottom))

To get colors assigned to different data points, you can either reformat your data as a DataFrame

Forces = vcat(
DataFrame(t = t_model, F = data_model, Source = "Model"),
DataFrame(t = t_exp, F = data_exp, Source = "Measured"))

plot(Forces, x = :t, y = :F, color = :Source, Geom.line)

or explicitly specify the color grouping

plot(x = [t_model, t_exp], y = [data_model, data_exp], 
     color = [fill("Model", length(t_model)), fill("Measured", length(t_exp))], 
     Geom.line)

[CorySimon]

+1
The :right position is I think unacceptable for many journals because of the white space that it wastes. The :top is much better, but still it would be great to be able to put the legends inside the plot, like in matplotlib.

[v-i-s-h]

Hi,
when I use :top , entries in the legend gets crowded to left alignment.
Is there any way to nicely spread them out evenly across the horizontal space?

[Mattriks]

using DataFrames, Gadfly, RDatasets
iris = dataset("datasets","iris")

d = Dict{String,String}("setosa"=>"setosa \t","versicolor"=>"versicolor \t", "virginica"=>"virginica \t")
# Add a new variable to the dataframe:
iris[:g] = map(x -> d[x], iris[:Species])

cscale = Scale.color_discrete_manual(colorant"red", colorant"green", colorant"blue")
theme1 = Theme(key_max_columns=3, key_position=:top, guide_title_position=:left)

p = plot(iris, x = :SepalWidth, y = :SepalLength, color = :g, Geom.point, 
    cscale, Guide.colorkey(""),
    theme1
)

[Mattriks]

Now back to the initial question in this issue (again using the iris dataset). Note in the code below its possible to use absolute e.g. context(7,6) or relative e.g. context(0.75w, 0.25h) coordinates to locate the key. If using absolute coordinates note the y-coord doesn't match the plot coords, presumably because of the way the key is rendered for 'outside' use.

using Compose
key = Guide.manual_color_key("Iris", ["setosa","versicolor","virginica"], ["red","green","blue"])
# Try changing ctxs[1] to ctxs[2] or ctxs[3] in the line below
# It seems Gadfly automatically renders 3 possible keys
mykey = render(key, Theme(), Gadfly.Aesthetics())[1].ctxs[1]
# Try changing context(7,6) to context(0.75w,0.25h) in the next line
kctx = compose(context(), (context(7,6), mykey))

p = plot(iris, x = :SepalLength, y = :PetalLength, color = :g, Geom.point, 
    cscale, Theme(key_position=:none),
    Guide.annotation(kctx)
)

[Mattriks]

This feature was added in #1087.
For discussion on overlapping labels see #859.