Book Image

Kivy: Interactive Applications in Python

By : Roberto Ulloa
4 (1)
Book Image

Kivy: Interactive Applications in Python

4 (1)
By: Roberto Ulloa

Overview of this book

Mobiles and tablets have brought with them a dramatic change in the utility of applications. Compatibility has become essential, and this has increased the kind of interaction that users expect: gestures, multi-touches, animations, and magic pens. Kivy is an open source Python solution that covers these market needs with an easy-to-learn and rapid development approach. Kivy is growing fast and gaining attention as an alternative to the established developing platforms. Kivy: Interactive Applications in Python quickly introduces you to the Kivy development methodology. You will learn some examples of how to use many of the Kivy components, as well as understand how to integrate and combine them into big projects. This book serves as a reference guide and is organized in such a way that once finished, you will have already completed your first project. You will start by learning the Kivy Language for building User Interfaces (UI) and vector figures. We then proceed to the uses of Kivy events and properties to glue the UI with the application logic. You then go on to build an entire User Interface (UI) starting from a hand-made sketch. Furthermore, you will go on to understand how to use the canvas and drawing instructions to create different types of geometrical figures. Finally, you will be introduced to a big set of interactive and smooth features: transformations (scale, rotate, and translate), gestures, animations, scheduling tasks, and multi-touch elements. Kivy: Interactive Applications in Python expands your knowledge by introducing various components that improve the User Experience (UX). Towards the end of the book, you will be confident to utilize Kivy components and strategies to start any application or game you have in mind.
Table of Contents (13 chapters)
Kivy: Interactive Applications in Python
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Screen manager – selecting colors for the figures


The ScreenManager class lets us handle different screens in the same window. In Kivy, screens are preferred over windows because we are programming for different devices with different screen sizes. Therefore, it is difficult (if not impossible) to have windows that adapt properly to all devices.

So far, all our figures have been of the same color and that is boring. So, let us allow the user to add some color to make the Comic Creator more fun. Kivy provides us with a Widget called ColorPicker, which is displayed in the following screenshot:

Kivy Color Picker

As you can see, this Widget requires a wide space, so it is difficult to accommodate it in our current interface. Let's use a ScreenManager instance to solve this problem. This basically allows us to have multiple screens instead of just one Widget (ComicCreator) and switch easily between them. The following is a new Kivy file (comicscreenmanager.kv) that contains the ComicScreenManager...