Python 2.6 Graphics Cookbook

Python 2.6 Graphics Cookbook

By : Michael J Ohlson

Buy this Book

Python 2.6 Graphics Cookbook

By: Michael J Ohlson

Buy this Book

Overview of this book

Python is a great object-oriented and interactive programming language that lets you develop graphics, both static and animated, using built-in vector graphics functions that are provided with Python. Python 2.6 Graphics Cookbook is a collection of straightforward recipes and illustrative screenshots for creating and animating graphic objects using the Python language. This book makes the process of developing graphics interesting and entertaining by working in a graphic workspace without the burden of mastering complicated language definitions and opaque examples. If you choose to work through all the recipes from the beginning, you will learn to install Python and create basic programs for making lines and shapes using the built-in Tkinter module. The confusing topic of color manipulation is explored in detail using existing Python tools as well as some new tools in the recipes. Next you will learn to manipulate font size, color, and placement of text as placing text exactly where you want on a screen can be tricky because font height, inter-character spacing, and text window dimensions all interfere with each other. Then you will learn how to animate graphics, for example having more than one independent graphic object co-exist and interact using various Python methods. You will also learn how you can work with raster images, such as converting their formats using the Python Imaging Library. Next you will learn how you can combine vector images with raster images so that you can animate the raster images with ease. You will also walk through a set of recipes with the help of which you can handle and manipulate blocks of raw data that may be hundreds of megabytes in size using datastreams, files, and hard drives. You will also learn how you can use Inkscape to dismantle existing images and use parts of them for your own graphics and Python programs. At the end of the book you will learn how you can create GUIs for different purposes.

Python 2.6 Graphics Cookbook

Credits

About the Author

About the Reviewers

Preface

Free Chapter

Start your Engines

Introduction

Running a shortest Python program

Ensuring that the Python modules are present

A basic Tkinter program

Make a compiled executable under Windows and Linux

Drawing Fundamental Shapes

Introduction

A straight line and the coordinate system

Draw a dashed line

Lines of varying styles with arrows and endcaps

A two segment line with a sharp bend

A line with a curved bend

Drawing intricate shapes – the curly vine

Draw a rectangle

Draw overlapping rectangles

Draw concentric squares

A circle from an oval

Cloning and resizing stars

Handling Text

Introduction

Simple text

Text font type, size, and color

Alignment of text – left and right justify

All the fonts available on your computer

Animation Principles

Introduction

Static shifting of a ball

Time-controlled shifting of a ball

Complete animation using draw-move-pause-erase cycles

More than one moving object

A ball that bounces

Bouncing in a gravity field

Precise collisions using floating point numbers

Trajectory tracing and ball-to-ball collisions

Rotating line

Trajectory tracing on multiple line rotations

A rose for you

The Magic of Color

Introduction

A limited palette of named colors

Nine ways of specifying color

A red beachball of varying hue

A red color wedge of graded hue

Newton's grand wheel of color mixing

The numerical color mixing matching palette

The animated graded color wheel

Tkinter's own color picker-mixer

Working with Pictures

Opening an image file and discovering its attributes

Open, view, and save an image in a different file format

Image format conversion for JPEG, PNG, TIFF, GIF, BMP

Image rotation in the plane of the image

Image size alteration

Correct proportion image resizing

Separating one color band in an image

Red, green, and blue color alteration in images

Slider controlled color manipulation

Combining images by blending

Blending images by varying percentages

Make a composite image using a mask image

Offset (roll) image horizontally and vertically

Flip horizontally, vertically, and rotate

Filter effects: blur, sharpen, contrast, and so on

Combining Raster and Vector Pictures

Simple animation of a GIF beach ball

The vector walking creature

Bird with shoes walking in the Karroo

Making GIF images with transparent backgrounds using GIMP

Diplomat walking at the palace

Spider in the forest

Moving band of images

Continuous band of images

Endless background

Data In and Data Out

Introduction

Creation of a new file on a hard drive

Writing data to a newly-created file

Writing data to multiple files

Adding data to existing files

Saving a Tkinter-drawing shape to disk

Retrieving Python data from disk storage

Simple mouse input

Storing and retrieving a mouse-drawn shape

A mouse-line editor

All possible mouse actions

Exchanging Inkscape SVG Drawings with Tkinter Shapes

Introduction

The structure of an SVG drawing

Tracing the shape of an image in Inkscape

Converting an SVG path into a Tkinter Line

GUI Construction: Part 1

Introduction

Widget configuration – a label

Button focus

The simplest push button with validation

A data entry box

Colored button causing a message pop-up

Complex interaction between buttons

Images on buttons and button packing

Grid Geometry Manager and button arrays

Drop-down menus to select from a list

Listbox variable selection

Text in a window

GUI Construction: Part 2

Introduction

The Grid Layout Geometry Manager

The Pack Geometry Manager

Radiobuttons to select one from many

Checkbuttons (Tickboxes) to select some of many

Key-stroke event handling

Scrollbar

Custom DIY controller widgets

Organizing widgets inside frames

Quick tips for running Python programs in Microsoft Windows

Running Python programs in Microsoft Windows

Where will we find the windows installer?

Do we have to use Python version 2.7?

Why do we get "python is not recognized…"?

Index

Customer Reviews

5 star

4 star

3 star

2 star

1 star

Writing data to a newly-created file

We now create a file and then write a small amount of data to it. The value of these very, very simple recipes is that when we are trying some task that is complex and things do not work as expected, the simple one-action-only test programs allow us to break our problem down into simple tasks that we can gradually add complexity to, verifying the validity of each new change. This is a tried and trusted philosophy used by many of the best programmers.

# file_write_1.py
#>>>>>>>>>>>>>
# Let's create a file and write it to disk.
filename = "/constr/test_write_1.dat"
filly = open(filename,"w")           # Create a file object, in write # mode

for i in range(0,2):
    filly.write("everything inside quotes is a string, even 3.1457")
    filly.writelines("\n")
    filly.write("How will stored data be delimited so we can read \ chunks of it into elements of list, tuple or dictionart?")
    filly.writelines("\n")
#filly.close...

Python 2.6 Graphics Cookbook

By : Michael J Ohlson

Python 2.6 Graphics Cookbook

By: Michael J Ohlson

Overview of this book

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Python 2.6 Graphics Cookbook

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