Gain insights into computer graphics with Python's Pycairo library. Learn about pixel vs. vector graphics, create complex shapes, work with transforms, text, gradients, and more for VR and game development.

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Pycairo

In this course, you will use Python’s Pycairo library to draw complex shapes. So if you have an appetite for virtual reality, or game development, then this course will serve you well.

You will start with basic concepts like: What is the difference between pixel and vector graphics? After that, you will learn to make basic drawings and then you will move on to complex shapes. Throughout, you will cover important concepts like transform and state, working with text, gradients, and a whole lot more.

By the time you finish this course, you will have a powerful new library at your disposal, and you’ll be able to construct beautiful graphics that users will love.

Computer Graphics in Python and Pycairo

# Arcs
An **arc** is a part of the circumference of a circle. The arc function is called like this: `ctx.arc(cx,cy,r,a1,a2)`

The following image shows how these parameters are used to draw an arc:


The arc is part of a circle, with radius `r` and centered at the point (`cx`, `cy`). It starts at angle `a1` and ends at angle `a2`. Angles are measured from the x-axis and, by default, increase as we move clockwise. Here is an example of the code used to draw an arc:

import cairo
import math

# Set up pycairo
surface = cairo.ImageSurface(cairo.FORMAT_RGB24, 600, 400)
ctx = cairo.Context(surface)
ctx.set_source_rgb(0.8, 0.8, 0.8)
ctx.paint()

# Draw an arc
ctx.arc(300, 200, 150, 0, math.pi/2)
ctx.set_source_rgb(1, 0, 0)
ctx.set_line_width(10)
ctx.stroke()

Angles in Python, as in most computer languages, are measured in radians rather than degrees. The pi radians are exactly 180 degrees. That makes 1 radian equal to approximately 57.3 degrees.

The code given above draws an arc of a circle, with its center located at `(300, 200)`: The middle of the image. The circle radius is 150, and the arc goes from angle 0 to angle pi/2 radians, which is a quarter of a turn. Run the code to see how the image looks.

Learn to make circles and curves with Pycairo.

Introduction

Introduction to Vector Graphics

Basic Drawing Operations

Paths and Complex Shapes

Computer Color

Transforms and State

Working with Text

Gradients and Image Fills

Clipping, Masking and Compositing

Surfaces and Output Formats

Integration with Other Libraries

Conclusion

Circle and Curves

Arcs