Put the standard imports for Matplotlib, Numpy and the IPython widgets in the following cell.
In [3]:
from matplotlib import pyplot as plt
import numpy as np
from IPython.display import SVG
from IPython.display import display
from IPython.html.widgets import interactive, fixed
SVG is a simple way of drawing vector graphics in the browser. Here is a simple example of how SVG can be used to draw a circle in the Notebook:
In [4]:
s = """
<svg width="100" height="100">
<circle cx="50" cy="50" r="20" fill="aquamarine" />
</svg>
"""
In [5]:
SVG(s)
Out[5]:
Write a function named draw_circle
that draws a circle using SVG. Your function should take the parameters of the circle as function arguments and have defaults as shown. You will have to write the raw SVG code as a Python string and then use the IPython.display.SVG
object and IPython.display.display
function.
In [6]:
def draw_circle(width=100, height=100, cx=25, cy=25, r=5, fill='red'):
"""Draw an SVG circle.
Parameters
----------
width : int
The width of the svg drawing area in px.
height : int
The height of the svg drawing area in px.
cx : int
The x position of the center of the circle in px.
cy : int
The y position of the center of the circle in px.
r : int
The radius of the circle in px.
fill : str
The fill color of the circle.
"""
circ_image = """
<svg width="%d" height="%d">
<circle cx="%d" cy="%d" r="%d" fill="%s" />
</svg>
"""%(width,height,cx,cy,r,fill)
display(SVG(circ_image))
In [7]:
draw_circle(cx=10, cy=10, r=10, fill='blue')
In [8]:
assert True # leave this to grade the draw_circle function
Use interactive
to build a user interface for exploing the draw_circle
function:
width
: a fixed value of 300pxheight
: a fixed value of 300pxcx
/cy
: a slider in the range [0,300]r
: a slider in the range [0,50]fill
: a text area in which you can type a color's nameSave the return value of interactive
to a variable named w
.
In [11]:
w = interactive(draw_circle,width = fixed(300),height = fixed(300),cx = (0,300),cy = (0,300,10),r = (0,50), fill = "red")
In [12]:
c = w.children
assert c[0].min==0 and c[0].max==300
assert c[1].min==0 and c[1].max==300
assert c[2].min==0 and c[2].max==50
assert c[3].value=='red'
Use the display
function to show the widgets created by interactive
:
In [13]:
display(w)
In [ ]:
assert True # leave this to grade the display of the widget
Play with the sliders to change the circles parameters interactively.