Bokeh – Customising Legends

The legend of a graph reflects the data displayed in the graph’s Y-axis. In Bokeh, the legends correspond to glyphs. This article how Legends appearing in the bokeh plot can be customized.

We can customize the legend with its several attributes such as location, color, line-color, font-size, font-style line width. We can modify it using the legend attribute with the required property name.

Syntax : legend.property_name=value

Parameter:

Here property name can take the following values

• location
• title
• label_text_font
• label_text_font_style
• label_text_color
• border_line_width
• border_line_color
• border_line_alpha
• background_fill_color
• background_fill_alpha

Approach

• Import module
• Draw a normal plot
• Customize accordingly
• Display plot

Example 1:

Python3

# import module
from bokeh.plotting import figure, show

# create data
currentList = [1, 2, 3, 4, 5]
List1 = [i*2 for i in currentList]
List2 = [i+2 for i in currentList]

# plot data
plots = figure(title=" your Legend Customization")

line = plots.line(
    currentList,
    List1,
    legend_label="Arrays .",
    line_color="blue",
    line_width=2
)

circle = plots.circle(
    currentList,
    List2,
    legend_label="List",
    fill_color="black",
    fill_alpha=0.4,
    line_color="blue",
    size=30,
)

# display legend in top right corner
plots.legend.location = "top_right"

# give title to legend
plots.legend.title = "Your observations"

# customize legend appearance
plots.legend.label_text_font = "times"
plots.legend.label_text_font_style = "italic"
plots.legend.label_text_color = "red"

# customize border and background of legend
plots.legend.border_line_width = 15
plots.legend.border_line_color = "pink"
plots.legend.border_line_alpha = 0.5
plots.legend.background_fill_color = "orange"
plots.legend.background_fill_alpha = 0.3

# display plot
show(plots)

Output :

Example 2 :

Python3

# import module
from bokeh.plotting import figure, show

# create data
currentList = [1, 2, 3, 4, 5]
List1 = [i*2 for i in currentList]
List2 = [i+2 for i in currentList]

# plot data
plots = figure(title="Legend Customization")

line = plots.line(currentList,
                  List1,
                  legend_label="Arrays .",
                  line_color="blue",
                  line_width=2
                 )

circle = plots.circle(
    currentList,
    List2,
    legend_label="List",
    fill_color="black",
    fill_alpha=0.5,
    line_color="blue",
    size=40,
)

# display legend in top left corner
plots.legend.location = "top_left"

#give title to legend
plots.legend.title = "Observation of plot"

#customize legend appearance
plots.legend.label_text_font = "times"
plots.legend.label_text_font_style = "bold"
plots.legend.label_text_color = "black"

# customize border and background of legend
plots.legend.border_line_width = 9
plots.legend.border_line_color = "green"
plots.legend.border_line_alpha = 0.7
plots.legend.background_fill_color = "magenta"
plots.legend.background_fill_alpha = 0.2

show(plots)

Output :

Example 3 :

Python3

# import module
from bokeh.plotting import figure, show

# create data
currentList = [1, 2, 3, 4, 5]
List1 = [i*2 for i in currentList]
List2 = [i+2 for i in currentList]

# plot data
plots = figure(title="Legend Customization")

line = plots.line(currentList,
                  List1,
                  legend_label="Arrays .",
                  line_color="blue",
                  line_width=2
                  )

circle = plots.circle(
    currentList,
    List2,
    legend_label="List",
    fill_color="black",
    fill_alpha=0.5,
    line_color="blue",
    size=50,
)

# display legend in top right corner
plots.legend.location = "top_center"

# give title to legend
plots.legend.title = " Your Observations "

# customize legend appearance
plots.legend.label_text_font = "times"
plots.legend.label_text_font_style = "normal"
plots.legend.label_text_color = "red"

# customize border and background of legend
plots.legend.border_line_width = 3
plots.legend.border_line_color = "grey"
plots.legend.border_line_alpha = 0.8
plots.legend.background_fill_color = "orange"
plots.legend.background_fill_alpha = 0.2

show(plots)

Output