Computer graphics in Python
Computer graphics in Python
Advanced vector graphics using Pycairo and Python
About the Book
The Pycairo library is a Python graphics library. This book covers the library in detail, with lots of practical code examples.
PyCairo is an efficient, fully featured, high quality graphics library, with similar drawing capabilities to other vector libraries and languages such as SVG, PDF, HTML canvas and Java graphics.
Typical use cases include: standalone Python scripts to create an image, chart, or diagram; server side image creation for the web (for example a graph of share prices that updates hourly); desktop applications, particularly those that involve interactive images or diagrams.
The power of Pycairo, with the expressiveness of Python, is also a great combination for making procedural images such as mathematical illustrations and generative art. It is also quite simple to generate image sequences that can be converted to video or animated gifs.
This book is primarily aimed at developers who have at least a small amount of Python experience, who are looking to use Python to create computer graphics for any application. The examples in the book use basic Python constructs, you don't need to be a Python guru to learn Pycairo. No prior knowledge of computer graphics is assumed, although if you have used other graphics systems you should still find this book useful as Pycairo has its own unique quirks and features.
Table of Contents
-
Foreword
- Who is this book for?
- About the author
- Keep in touch
-
1 Introduction to vector graphics
- 1.1 Pixel images
- 1.2 Size and resolution
- 1.3 Resizing pixel images
- 1.4 Drawing on pixel images
- 1.5 Vector graphics
- 1.6 Rendering
- 1.7 Typical uses
- 1.8 Benefits
- 1.9 Disadvantages
- 1.10 Common vector formats
-
2 About Pycairo
- 2.1 Cairo
- 2.2 Capabilities
- 2.3 Version
- 2.4 Installing Pycairo
- 2.5 Checking Pycairo version
-
3 Basic drawing operations
- 3.1 Creating an image with Pycairo
- 3.2 Coordinate system
- 3.3 Rectangles
- 3.4 Fill and stroke
- 3.5 Lines
- 3.6 Polygons
- 3.7 Open and closed shapes
- 3.8 Arcs
- 3.9 Circles
- 3.10 Bezier curves
- 3.11 Line styles
-
4 Paths and complex shapes
- 4.1 Paths
- 4.2 Sub-paths
- 4.3 Lines
- 4.4 Polygons
- 4.5 Arcs
- 4.6 Bezier curves
- 4.7 Function curves
- 4.8 Rectangle
-
5 Computer colour
- 5.1 RGB colour
- 5.2 Pycairo RGB colours
- 5.3 CSS named colours
- 5.4 Transparency
- 5.5 Transparency colour calculation
- 5.6 Transparent images
- 5.7 Greyscale images
- 5.8 Pixel colours
-
6 Transforms and state
- 6.1 User space and device space
- 6.2 Translation
- 6.3 Scaling
- 6.4 Rotation
- 6.5 Save and restore
- 6.6 Rotating about a point
- 6.7 Placing an ellipse
- 6.8 Correcting the effects of unequal scaling
- 6.9 Flipping
- 6.10 Current transform matrix
-
7 Working with text
- 7.1 Text is just shapes
- 7.2 How Pycairo handles text
- 7.3 Fonts
- 7.4 Font size
- 7.5 Font style
- 7.6 Text extents
- 7.7 Text extent examples
- 7.8 Text alignment
-
8 Gradients and image fills
- 8.1 Patterns
- 8.2 SolidPattern
- 8.3 Linear gradient
- 8.4 Linear gradients at different angles
- 8.5 Adding more stops
- 8.6 Extend options
- 8.7 Filling a stroke with a gradient
- 8.8 Filling text with a gradient
- 8.9 Radial gradients
- 8.10 Radial gradient with inner circle
- 8.11 Radial extend options
- 8.12 Loading an image into Pycairo
- 8.13 Using SurfacePattern with an image
- 8.14 SurfacePattern extend options
- 8.15 Using SurfacePattern with vectors
-
9 Clipping, masking and compositing
- 9.1 Clipping
- 9.2 Calling clip multiple times
- 9.3 Resetting the clip region
- 9.4 Clipping functions
- 9.5 Masking
- 9.6 Using an image as a mask
- 9.7 Compositing
- 9.8 OVER operator
- 9.9 Changing the drawing order
- 9.10 Masking operations
- 9.11 Artistic colour adjustments
- 9.12 Specific colour changes
-
10 Surfaces and output formats
- 10.1 Output formats
- 10.2 ImageSurface
- 10.3 SVGSurface
- 10.4 PDFSurface
- 10.5 PSSurface
- 10.6 RecordingSurface
- 10.7 ScriptSurface
- 10.8 TeeSurface
- 10.9 GUI surfaces
-
11 Integration with other libraries
- 11.1 How Pycairo stores image data
- 11.2 PIL (Pillow) integration
- 11.3 Numpy integration
-
12 Reference
- 12.1 Radians
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