Computer graphics in Python by Martin McBride_468 x 60.png

pycairo.tar.gz

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

## Introduction to spaces
Pycairo has two coordinate spaces: **user space** and **device space**. By default, these two spaces are identical, which is why we treat them as one space. However, we can modify user space and get useful results.

User space is the coordinate system that we, as programmers, use to draw things in Pycairo. When we draw a rectangle that is 200 units by 100 units, those units are **user space units**.

Device space is the coordinate system Pycairo uses internally to draw images. If we use Pycairo to create a PNG image, *1 unit in device space* will correspond to *1 pixel of the output image*.

>If we use Pycairo to create a vector output (such as an SVG file), *1 unit in device space* will correspond to *1 “unit” in the vector file.* However, since vector formats like SVG are scalable, this unit can be anything we want it to be.

Once we define a Pycairo `Surface`, the device space is fixed and user space can be changed as per our requirements.

Here is a diagram of user space and device space for a surface that was defined as 550 units by 550 units:

# Introduction to spaces
Pycairo has two coordinate spaces: **user space** and **device space**. By default, these two spaces are identical, which is why we treat them as one space. However, we can modify user space and get useful results.

User space is the coordinate system that we, as programmers, use to draw things in Pycairo. When we draw a rectangle that is 200 units by 100 units, those units are **user space units**.

Device space is the coordinate system Pycairo uses internally to draw images. If we use Pycairo to create a PNG image, *1 unit in device space* will correspond to *1 pixel of the output image*.

>If we use Pycairo to create a vector output (such as an SVG file), *1 unit in device space* will correspond to *1 “unit” in the vector file.* However, since vector formats like SVG are scalable, this unit can be anything we want it to be.

Once we define a Pycairo `Surface`, the device space is fixed and user space can be changed as per our requirements.

Here is a diagram of user space and device space for a surface that was defined as 550 units by 550 units:

In this lesson, we'll cover user and device space in 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

User Space and Device Space

Introduction to spaces