PyCairo – Drawing the Roundrect

In this article, we will learn how we can draw a simple Roundrect shape using PyCairo in python. A roundrect is a rectangle with rounded corners

PyCairo : Pycairo is a Python module providing bindings for the cairo graphics library. This library is used for creating SVG i.e vector files in python. The easiest and quickest way to open an SVG file to view it (read-only) is with a modern web browser like Chrome, Firefox, Edge, or Internet Explorer—nearly all of them should provide some sort of rendering support for the SVG format.  

SVG file is a graphics file that uses a two-dimensional vector graphic format created by the World Wide Web Consortium (W3C). It describes images using a text format that is based on XML. SVG files are developed as a standard format for displaying vector graphics on the web.

Steps of Implementation :

• Import the Pycairo module.
• Create an SVG surface object and add context to it.
• Creating a function to make roundrect shape
• Calling the function with parameters
• Setting color of the context & line width

Below is the Implementation :

Python3

# importing pycairo
import cairo
import math

# Creating function for make roundrect shape
def roundrect(context, x, y, width, height, r):
    context.arc(x+r, y+r, r,
                math.pi, 3*math.pi/2)

    context.arc(x+width-r, y+r, r,
                3*math.pi/2, 0)

    context.arc(x+width-r, y+height-r,
                r, 0, math.pi/2)

    context.arc(x+r, y+height-r, r,
                math.pi/2, math.pi)

    context.close_path()
    # creating a SVG surface
    # here geek95 is file name &
    # 700, 700 is dimension


with cairo.SVGSurface("geek95.svg", 700, 700) as surface:

    # creating a cairo context object for SVG surface
    # using Context method
    context = cairo.Context(surface)

    # setting width of the context
    context.set_line_width(10)

    # setting color of the context
    context.set_source_rgb(0, 0, 0.5)

    # Call the function
    roundrect(context, 100, 100, 400, 200, 50)

    # stroke out the color and width property
    context.stroke()

# printing message when file is saved
print("File Saved")

Output :