Kivy Blueprints

Mark Vasilkov

• Publisher: Packt Publishing
• Year: 2015
• eBook ISBN: 9781783987849
• Topic: Computer Science
• Subtopic: Open Source Programming
• Index: Computer Science

Kivy Blueprints

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Table of Contents

Kivy Blueprints

Credits

About the Author

About the Reviewers

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Preface

Write once, run anywhere

What this book covers

Setting up the working environment

A note on Python

Installing and running Kivy

Note on coding

Hello, Kivy

Code

Layout

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Downloading the color images of this book

Errata

Piracy

Questions

1. Building a Clock App

The starting point

Modern UI

Design inspiration

Loading custom fonts

Formatting text

Changing the background color

Making the clock tick

Updating the time on the screen

Binding widgets using properties

Layout basics

Finalizing the layout

Reducing repetition

Named classes

Styling buttons

9-patch scaling

Using 9-patch images

Counting time

Formatting the time for stopwatch

Computing values

Putting a stopwatch in place

Stopwatch controls

Summary

2. Building a Paint App

Setting the stage

Fine-tuning the looks

Visual appearance

Window size

Mouse cursor

Multitouch emulation

Drawing touches

A very short introduction to the canvas

Displaying touches on the screen

Clearing the screen

Passing events

Clearing the canvas

Connecting the dots

The color palette

Subclassing the buttons

Taking away the ability to deselect

Overriding the standard behavior

Coloring buttons

A new kind of button

Defining the palette

Setting the line thickness

Changing the line width

Summary

3. Sound Recorder for Android

Writing platform-dependent code

Introducing Pyjnius

Emulating Android

Metro UI

The buttons

The grid structure

Visual attributes

Scalable vector icons

Icon fonts

Rationale for using icon fonts

Using the icon font in Kivy

Testing on Android

Using the native API

Loading Java classes

Looking up the storage path

Reading logs from the device

Recording sound

Major caveat – permissions

Playing sound

Deleting files

Summary

4. Kivy Networking

Writing the chat server

The protocol definition

The server source code

The principle of operation

Testing the server

Screen manager

Customizing the animation

Login screen layout

Chatroom screen layout

Overscroll modes

Bringing the app online

Building a simple Python client

Kivy integration with Twisted

ChatClient and ChatClientFactory

UI integration

Application logic of the client

Cross-application interoperability

Enhancements and eye candy

Escaping the special syntax

What's next

Summary

5. Making a Remote Desktop App

The server

The Flask web server

Advanced server functionality – taking screenshots

Emulating clicks

JavaScript client

Endless loop of screenshots

Passing clicks to host

Kivy Remote Desktop app

The login form

The remote desktop screen

Loop of screenshots in Kivy

Sending clicks

What's next

Summary

6. Making the 2048 Game

About the game

Gameplay concepts and overview

Randomness, or lack thereof

The 2048 project outline

What makes 2048 a good choice of project?

Simplicity as a feature

Creating the 2048 board

Going through cells

Rendering empty cells

Board data structure

Variable naming

Calling reset()

Testing passability

Making tiles

Tile initialization

Resizing tiles

Implementing the game logic

Moving tiles

Controlling the iteration sequence

Implementing the move() method

Binding touch controls

Combining tiles

Adding more tiles

Synchronizing turns

Game over

The winning condition

The loss condition

Where to go from here

Summary

7. Writing a Flappy Bird Clone

Project overview

Creating an animated background

Loading tileable textures

The Background widget

Animating the background

Making pipes

An overview of the pipe properties

Setting texture coordinates

Implementing pipes

Spawning pipes

Moving and recycling pipes

Introducing Kivy Bird

Revised application flow

Accepting user input

Learning to fly straight down

Remaining in flight

Rotating the bird

Collision detection

Game over

Producing sound effects

Kivy sound playback

Adding sound to the Kivy Bird game

Summary

8. Introducing Shaders

Unscientific introduction to OpenGL

Concepts and parallelism

Performance gains, or lack thereof

Improving performance

Taking a closer look at GLSL

Using custom shaders in Kivy

Building the geometry

Illustrating the Indices

Writing GLSL

Storage classes and types

Basic shaders

Procedural coloring

Colorful vertices

Texture mapping

Making the Starfield app

Application structure

Data structures and initializers

Advancing the scene

Writing a corresponding GLSL

Summary

9. Making a Shoot-Em-Up Game

Limitations of the project

Texture atlases at a glance

Creating an atlas

Atlas structure

Using Kivy atlases in an easy way

Ad hoc usage of atlases with GLSL

Data structure for UV mapping

Writing an atlas loader

Rendering sprites from atlas

Designing a reusable particle system

Class hierarchy

The PSWidget renderer class

The Particle class

Writing the game

Implementing stars

Making a spaceship

Creating a trail of fire

Making bullets

Implementing enemies

Collision detection

Finishing touches

Summary

A. The Python Ecosystem

Index

Kivy Blueprints

Copyright © 2015 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: January 2015

Production reference: 1230115

Published by Packt Publishing Ltd.

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Table of contents

• Kivy Blueprints