First steps 2: Adding and customizing renderers¶
In the previous first steps guide, you used Bokeh’s
figure()
function to render line charts.
In this section, you will use different renderer functions to create various other kinds of graphs. You will also customize what your glyphs look like.
Rendering different glyphs¶
Bokeh’s plotting interface supports many different glyphs, such as lines, bars, hex tiles, or other polygons.
See also
A full list of all supported glyph methods is available in Bokeh’s reference
guide for the figure()
function. For detailed
information on Bokeh’s glyphs, see Plotting with basic glyphs in Bokeh’s user
guide.
Rendering circles¶
Use the circle()
function instead of
line()
to render circles:
p.circle(x, y3, legend_label="Objects", line_color="yellow", size=12)
Add the circle()
function to your previous
visualization:
from bokeh.plotting import figure, show
# prepare some data
x = [1, 2, 3, 4, 5]
y1 = [6, 7, 2, 4, 5]
y2 = [2, 3, 4, 5, 6]
y3 = [4, 5, 5, 7, 2]
# create a new plot with a title and axis labels
p = figure(title="Multiple glyphs example", x_axis_label="x", y_axis_label="y")
# add multiple renderers
p.line(x, y1, legend_label="Temp.", line_color="blue", line_width=2)
p.line(x, y2, legend_label="Rate", line_color="red", line_width=2)
p.circle(x, y3, legend_label="Objects", line_color="yellow", size=12)
# show the results
show(p)
Rendering bars¶
Similarly, use the vbar()
function to render
vertical bars:
p.vbar(x=x, top=y2, legend_label="Rate", width=0.5, bottom=0, color="red")
Add the vbar()
function to your previous
visualization:
from bokeh.plotting import figure, show
# prepare some data
x = [1, 2, 3, 4, 5]
y1 = [6, 7, 2, 4, 5]
y2 = [2, 3, 4, 5, 6]
y3 = [4, 5, 5, 7, 2]
# create a new plot with a title and axis labels
p = figure(title="Multiple glyphs example", x_axis_label="x", y_axis_label="y")
# add multiple renderers
p.line(x, y1, legend_label="Temp.", line_color="blue", line_width=2)
p.vbar(x=x, top=y2, legend_label="Rate", width=0.5, bottom=0, color="red")
p.circle(x, y3, legend_label="Objects", line_color="yellow", size=12)
# show the results
show(p)
See also
To learn more about bar graphs and other ways Bokeh handles categorical data, see Handling categorical data in the user guide.
Customizing glyphs¶
The different renderer functions accept various arguments to control what your glyphs look like.
Defining properties of new glyphs¶
The circle()
function, for example, lets you
define aspects like the color or diameter of the circles:
fill_color
: the fill color of the circlesfill_alpha
: the transparency of the fill color (any value between0
and1
)line_color
: the fill color of the circles’ outlinessize
: the size of the circles (in screen units or data units)legend_label
: legend entry for the circles
In Bokeh, you can specify colors in several ways. For example:
Use one of the named CSS colors (for example,
"firebrick"
)Use hexadecimal values, prefaced with a
#
(for example"#00ff00"
)Use a 3-tuple for RGB colors (for example,
(100, 100, 255)
Use a 4-tuple for RGBA colors (for example
(100, 100, 255, 0.5)
)
Create circles with the legend label “Objects” and make the circles appear slightly transparent with a red fill color and blue outlines:
from bokeh.plotting import figure, show
# prepare some data
x = [1, 2, 3, 4, 5]
y = [4, 5, 5, 7, 2]
# create a new plot with a title and axis labels
p = figure(title="Glyphs properties example", x_axis_label="x", y_axis_label="y")
# add circle renderer with additional arguments
p.circle(
x,
y,
legend_label="Objects",
fill_color="red",
fill_alpha=0.5,
line_color="blue",
size=80,
)
# show the results
show(p)
Altering properties of existing glyphs¶
If you want to change any property after creating an object, you can define and overwrite the object’s attributes directly.
Take the circles from above, for example. You defined the circles to have a
red color by passing the argument fill_color="red"
.
To change the color of your circles from red to blue, you first need to assign
a variable name (such as circle
) to the new object when you call the
circle()
function.
circle = p.circle(
x,
y,
legend_label="Objects",
fill_color="red",
fill_alpha=0.5,
line_color="blue",
size=80,
)
Next, use that variable to access the object’s glyph
attribute and change
its properties:
glyph = circle.glyph
glyph.fill_color = "blue"
Generate red circles once more, but this time change their color to blue before outputting the plot:
from bokeh.plotting import figure, show
# prepare some data
x = [1, 2, 3, 4, 5]
y = [4, 5, 5, 7, 2]
# create a new plot with a title and axis labels
p = figure(title="Glyphs properties example", x_axis_label="x", y_axis_label="y")
# add circle renderer with additional arguments
circle = p.circle(
x,
y,
legend_label="Objects",
fill_color="red",
fill_alpha=0.5,
line_color="blue",
size=80,
)
# change color of previously created object's glyph
glyph = circle.glyph
glyph.fill_color = "blue"
# show the results
show(p)
See also
For more information about the various visual properties, see Styling glyphs and Customizing visual properties in the user guide.
Each type of glyph has different properties. Refer to
figure()
in the reference guide to see all available
properties for each glyph method.