Search icon CANCEL
Subscription
0
Cart icon
Your Cart (0 item)
Close icon
You have no products in your basket yet
Save more on your purchases! discount-offer-chevron-icon
Savings automatically calculated. No voucher code required.
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Newsletter Hub
Free Learning
Arrow right icon
timer SALE ENDS IN
0 Days
:
00 Hours
:
00 Minutes
:
00 Seconds
Kivy Cookbook
Kivy Cookbook

Kivy Cookbook: Enhance your skills in developing multi-touch applications with Kivy

Arrow left icon
Profile Icon Hugo Solis Profile Icon Solis
Arrow right icon
€18.99 per month
Full star icon Full star icon Half star icon Empty star icon Empty star icon 2.5 (2 Ratings)
Paperback Aug 2015 246 pages 1st Edition
eBook
€8.99 €32.99
Paperback
€41.99
Subscription
Free Trial
Renews at €18.99p/m
Arrow left icon
Profile Icon Hugo Solis Profile Icon Solis
Arrow right icon
€18.99 per month
Full star icon Full star icon Half star icon Empty star icon Empty star icon 2.5 (2 Ratings)
Paperback Aug 2015 246 pages 1st Edition
eBook
€8.99 €32.99
Paperback
€41.99
Subscription
Free Trial
Renews at €18.99p/m
eBook
€8.99 €32.99
Paperback
€41.99
Subscription
Free Trial
Renews at €18.99p/m

What do you get with a Packt Subscription?

Free for first 7 days. $19.99 p/m after that. Cancel any time!
Product feature icon Unlimited ad-free access to the largest independent learning library in tech. Access this title and thousands more!
Product feature icon 50+ new titles added per month, including many first-to-market concepts and exclusive early access to books as they are being written.
Product feature icon Innovative learning tools, including AI book assistants, code context explainers, and text-to-speech.
Product feature icon Thousands of reference materials covering every tech concept you need to stay up to date.
Subscribe now
View plans & pricing
Table of content icon View table of contents Preview book icon Preview Book

Kivy Cookbook

Chapter 2. Input, Motion, and Touch

In this chapter, we will cover:

  • Using the mouse
  • Evolving to the touchscreen
  • Working with the accelerometer
  • Using the gyroscope
  • The Differences between the touch and motion events
  • Recognizing touch shapes
  • Detecting multitapping
  • Grabbing touch events
  • Recording gestures

Introduction

The Kivy framework is able to handle most common types of input and actions such as mouse, touchscreen, accelerometer, and gyroscope that will be reviewed in this chapter. It handles the native multitouch protocols on the following platforms: Tuio, WM_Touch, MacMultitouchSupport, MT Protocol A/B, and Android.

The class of all input events is motion event. It generates two kinds of events; one of them is touch events—a motion event that contains at least an x and y position. All the touch events are dispatched across the widget tree. The no-touch events are the rest. The accelerometer is a continuous event, without position. It never starts or stops. These events are not dispatched across the widget tree.

Using the mouse

This recipe will teach you how to use the first kind of input, probably the most used, the mouse. We will consider the mouse input as a touch event, so the (x, y) position of the touch (0-1 range) will be scaled to the window size (width/height) and dispatched to the following:

  • on_touch_down: An event is fired when a touch down event is initiated. Subsequently, the respective widget's on_touch_down() method is called.
  • on_touch_move: An event is fired when a touch event moves (changes location). Subsequently, the respective widget's on_touch_move() method is called.
  • on_touch_up: An event is fired when a down event is released (terminated). Subsequently, the respective widget's on_touch_up() method is called.

Getting ready

In this recipe, we will use the Kv language for the design of the widgets, so you will need to be familiar with the language or have completed the previous chapter. Also, this recipe will use the common Button widget for reference.

How to do it...

Evolving to the touchscreen

In this recipe, we are evolving to the touchscreen. Here, you will see the basic differences between the mouse and the touchscreen. This will give us more options than with the mouse device.

Getting ready

For this recipe, we will use the Kv language for the design of the widgets, so make sure that you are confident with it and refresh your knowledge if necessary. Also, this recipe will use the common button and label widgets for reference. Obviously, to get more benefit, a touchscreen device is useful to run the code.

How to do it…

Perform the following steps:

  1. In the KV file, declare the button and the label:
    <MyW>:
        Button:
            id: button1
            text: 'Hello'
        Label:
            id: label1
            pos: 100, 100
            text: 'My label before press the screen'
  2. In the class of the widget in the Python code, we need to override the method on_touch_down
  3. Change the button text with the information in touch.button
  4. Change the label text...

Working with the accelerometer

Nowadays, it is common that mobile devices are equipped with an accelerometer. Thereby, it is relevant to consider this input to develop fancy apps. The accelerometer is one kind of event that is considered as a no-touch event because it has neither start nor an end, it is always providing information.

Getting ready

In this recipe, we will use the Kv language for the design of the widgets, so, again, you will need to be familiar with the Kv language. Also, this recipe will use the common button and label widgets for reference. Obviously, to get more benefit, a device with an accelerometer is useful to run the code.

It is necessary to install a package for the use of the accelerometer in any mobile device; there is a way to deal with every specific device, but we do not have to reinvent the wheel. Let's use a Plyer package, which is an effort from many of the Kivy developers. To install the package from the shell, use:

$ sudo pip plyer install

Here where we...

Using the gyroscope

Mobile devices today also have a gyroscope. The gyroscope is considered as a no-touch event. This kind of event does not have a start or an end; it is always providing information.

Getting ready

For this recipe, we will use the Kv language for the design of the widgets. Also, this recipe will use the common button and label widgets for reference. Obviously, to run the code of this recipe properly, a device with a gyroscope is necessary.

It is necessary to install a package to use the gyroscope with any mobile device. While there is a way to deal with specific devices, we do not have to reinvent the wheel. Let's use the plyer package, which is an effort from many of the Kivy developers. To install the package from the shell, use:

$ sudo pip plyer install

How to do it…

To complete this recipe, follow these steps:

  1. In the KV file, define the four labels and the button:
    <Acce>:
        Label:
            id: label1
            pos: 150, 300
            text: 'X: '
    
    ...

The differences between the touch and motion events

There is a key difference between touch and motion events. A motion event is a continuous succession of many touch events. However, we also know that a touch event always has the pos profile, namely position information. The motion event, however, is not dispatched throughout the widget tree.

Getting ready

In this recipe, we will use the Kv language for the design of the widgets, so we assume that the reader is familiar with the Kv language or did the lecture of the first chapter. Also, this recipe will use the common button widget for reference.

How to do it…

Use this recipe and follow these steps:

  1. First, in the KV file, define a button:
    <MyW>:
        Button:
            id: button1
            pos: 0,0
            text: 'Hello'
  2. In the class of the widget in the Python code, we need to override the method on_touch_move.
  3. Change the button's position with the information in touch.pos:
    import kivy
    kivy.require('1.9.0') 
    
    from...

Introduction


The Kivy framework is able to handle most common types of input and actions such as mouse, touchscreen, accelerometer, and gyroscope that will be reviewed in this chapter. It handles the native multitouch protocols on the following platforms: Tuio, WM_Touch, MacMultitouchSupport, MT Protocol A/B, and Android.

The class of all input events is motion event. It generates two kinds of events; one of them is touch events—a motion event that contains at least an x and y position. All the touch events are dispatched across the widget tree. The no-touch events are the rest. The accelerometer is a continuous event, without position. It never starts or stops. These events are not dispatched across the widget tree.

Using the mouse


This recipe will teach you how to use the first kind of input, probably the most used, the mouse. We will consider the mouse input as a touch event, so the (x, y) position of the touch (0-1 range) will be scaled to the window size (width/height) and dispatched to the following:

  • on_touch_down: An event is fired when a touch down event is initiated. Subsequently, the respective widget's on_touch_down() method is called.

  • on_touch_move: An event is fired when a touch event moves (changes location). Subsequently, the respective widget's on_touch_move() method is called.

  • on_touch_up: An event is fired when a down event is released (terminated). Subsequently, the respective widget's on_touch_up() method is called.

Getting ready

In this recipe, we will use the Kv language for the design of the widgets, so you will need to be familiar with the language or have completed the previous chapter. Also, this recipe will use the common Button widget for reference.

How to do it…

Follow the steps...

Evolving to the touchscreen


In this recipe, we are evolving to the touchscreen. Here, you will see the basic differences between the mouse and the touchscreen. This will give us more options than with the mouse device.

Getting ready

For this recipe, we will use the Kv language for the design of the widgets, so make sure that you are confident with it and refresh your knowledge if necessary. Also, this recipe will use the common button and label widgets for reference. Obviously, to get more benefit, a touchscreen device is useful to run the code.

How to do it…

Perform the following steps:

  1. In the KV file, declare the button and the label:

    <MyW>:
        Button:
            id: button1
            text: 'Hello'
        Label:
            id: label1
            pos: 100, 100
            text: 'My label before press the screen'
  2. In the class of the widget in the Python code, we need to override the method on_touch_down

  3. Change the button text with the information in touch.button

  4. Change the label text with the information in...

Working with the accelerometer


Nowadays, it is common that mobile devices are equipped with an accelerometer. Thereby, it is relevant to consider this input to develop fancy apps. The accelerometer is one kind of event that is considered as a no-touch event because it has neither start nor an end, it is always providing information.

Getting ready

In this recipe, we will use the Kv language for the design of the widgets, so, again, you will need to be familiar with the Kv language. Also, this recipe will use the common button and label widgets for reference. Obviously, to get more benefit, a device with an accelerometer is useful to run the code.

It is necessary to install a package for the use of the accelerometer in any mobile device; there is a way to deal with every specific device, but we do not have to reinvent the wheel. Let's use a Plyer package, which is an effort from many of the Kivy developers. To install the package from the shell, use:

$ sudo pip plyer install

Here where we are...

Left arrow icon Right arrow icon

Description

Kivy is an open-source Python library for rapid development of applications that make use of innovative user interfaces, such as multi-touch apps. It is a promising Python framework to develop UI and UX apps in a cross-platform environment, under the Python philosophy. Kivy Cookbook is a practical book that will guide you through the Kivy framework to develop apps and get your apps ready for distribution in App Store and Android devices. You will start off with installing Kivy and building your interfaces. You will learn how to work the accelerometer and create custom events. Then, you will understand how to use the basics, buttons, labels and text inputs and manipulate the widget tree. Next, you will be able to work with manipulating instructions, create an atlas and layouts. Moving on, you will learn packing for Windows and packing for iOS, and use TestDrive. By the end of the book, you will have learnt in detail the relevant features and tools in Kivy and how to create portable packages to distribute your apps in the most used platforms.

What you will learn

  • Access widgets defined inside Kv language in your Python code Handle Kivy events to control widgets, touches, the mouse, the keyboard, and animations Recognize touch shapes and detecting multi-tapping Create custom events and declare properties Organizing your layouts while working with the ActionBar Store and retrieve the coordinate space context Create your own shader and render in a framebuffer Leverage Factory objects, multi-touch in iOS and multi-touch in Android

Product Details

Country selected
Publication date, Length, Edition, Language, ISBN-13
Publication date : Aug 21, 2015
Length: 246 pages
Edition : 1st
Language : English
ISBN-13 : 9781783987382
Category :
Languages :
Tools :

What do you get with a Packt Subscription?

Free for first 7 days. $19.99 p/m after that. Cancel any time!
Product feature icon Unlimited ad-free access to the largest independent learning library in tech. Access this title and thousands more!
Product feature icon 50+ new titles added per month, including many first-to-market concepts and exclusive early access to books as they are being written.
Product feature icon Innovative learning tools, including AI book assistants, code context explainers, and text-to-speech.
Product feature icon Thousands of reference materials covering every tech concept you need to stay up to date.
Subscribe now
View plans & pricing

Product Details

Publication date : Aug 21, 2015
Length: 246 pages
Edition : 1st
Language : English
ISBN-13 : 9781783987382
Category :
Languages :
Tools :

Packt Subscriptions

See our plans and pricing
Modal Close icon
€18.99 billed monthly
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Simple pricing, no contract
€189.99 billed annually
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just €5 each
Feature tick icon Exclusive print discounts
€264.99 billed in 18 months
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just €5 each
Feature tick icon Exclusive print discounts

Frequently bought together


Stars icon
Total 115.97
Kivy ??? Interactive Applications and Games in Python second edition
€36.99
Kivy Cookbook
€41.99
Kivy Blueprints
€36.99
Total 115.97 Stars icon
Banner background image

Table of Contents

10 Chapters
1. Kivy and the Kv Language Chevron down icon Chevron up icon
2. Input, Motion, and Touch Chevron down icon Chevron up icon
3. Events Chevron down icon Chevron up icon
4. Widgets Chevron down icon Chevron up icon
5. Graphics – Canvas and Instructions Chevron down icon Chevron up icon
6. Advanced Graphics – Shaders and Rendering Chevron down icon Chevron up icon
7. The API in Detail Chevron down icon Chevron up icon
8. Packaging our Apps for PC Chevron down icon Chevron up icon
9. Kivy for Mobile Devices Chevron down icon Chevron up icon
Index Chevron down icon Chevron up icon

Customer reviews

Rating distribution
Full star icon Full star icon Half star icon Empty star icon Empty star icon 2.5
(2 Ratings)
5 star 0%
4 star 50%
3 star 0%
2 star 0%
1 star 50%
SL Sep 10, 2015
Full star icon Full star icon Full star icon Full star icon Empty star icon 4
This book covers Kivy for Python programmation language. Kivy helps you build graphical interfaces that run on all PC platforms and also on android and IOS. http://kivy.org/The cookbook format is quite convenient because it gives several recipes from extremely basic to more advanced ones. From launching a "hello world" app to packaging your app for distribution.So it's a good purchase and it was worth reading it.
Amazon Verified review Amazon
jooster Sep 07, 2017
Full star icon Empty star icon Empty star icon Empty star icon Empty star icon 1
I cannot recommend this book. Though the format fits my work/learning style, the example code is riddled with errors, problems and omissions. Right of the bat, the very first example (hello world) does not work as described. The remainder of the book is an exercise in frustration. I (tried to) made it through several examples before moving onto something else.
Amazon Verified review Amazon
Get free access to Packt library with over 7500+ books and video courses for 7 days!
Start Free Trial

FAQs

What is included in a Packt subscription? Chevron down icon Chevron up icon

A subscription provides you with full access to view all Packt and licnesed content online, this includes exclusive access to Early Access titles. Depending on the tier chosen you can also earn credits and discounts to use for owning content

How can I cancel my subscription? Chevron down icon Chevron up icon

To cancel your subscription with us simply go to the account page - found in the top right of the page or at https://subscription.packtpub.com/my-account/subscription - From here you will see the ‘cancel subscription’ button in the grey box with your subscription information in.

What are credits? Chevron down icon Chevron up icon

Credits can be earned from reading 40 section of any title within the payment cycle - a month starting from the day of subscription payment. You also earn a Credit every month if you subscribe to our annual or 18 month plans. Credits can be used to buy books DRM free, the same way that you would pay for a book. Your credits can be found in the subscription homepage - subscription.packtpub.com - clicking on ‘the my’ library dropdown and selecting ‘credits’.

What happens if an Early Access Course is cancelled? Chevron down icon Chevron up icon

Projects are rarely cancelled, but sometimes it's unavoidable. If an Early Access course is cancelled or excessively delayed, you can exchange your purchase for another course. For further details, please contact us here.

Where can I send feedback about an Early Access title? Chevron down icon Chevron up icon

If you have any feedback about the product you're reading, or Early Access in general, then please fill out a contact form here and we'll make sure the feedback gets to the right team. 

Can I download the code files for Early Access titles? Chevron down icon Chevron up icon

We try to ensure that all books in Early Access have code available to use, download, and fork on GitHub. This helps us be more agile in the development of the book, and helps keep the often changing code base of new versions and new technologies as up to date as possible. Unfortunately, however, there will be rare cases when it is not possible for us to have downloadable code samples available until publication.

When we publish the book, the code files will also be available to download from the Packt website.

How accurate is the publication date? Chevron down icon Chevron up icon

The publication date is as accurate as we can be at any point in the project. Unfortunately, delays can happen. Often those delays are out of our control, such as changes to the technology code base or delays in the tech release. We do our best to give you an accurate estimate of the publication date at any given time, and as more chapters are delivered, the more accurate the delivery date will become.

How will I know when new chapters are ready? Chevron down icon Chevron up icon

We'll let you know every time there has been an update to a course that you've bought in Early Access. You'll get an email to let you know there has been a new chapter, or a change to a previous chapter. The new chapters are automatically added to your account, so you can also check back there any time you're ready and download or read them online.

I am a Packt subscriber, do I get Early Access? Chevron down icon Chevron up icon

Yes, all Early Access content is fully available through your subscription. You will need to have a paid for or active trial subscription in order to access all titles.

How is Early Access delivered? Chevron down icon Chevron up icon

Early Access is currently only available as a PDF or through our online reader. As we make changes or add new chapters, the files in your Packt account will be updated so you can download them again or view them online immediately.

How do I buy Early Access content? Chevron down icon Chevron up icon

Early Access is a way of us getting our content to you quicker, but the method of buying the Early Access course is still the same. Just find the course you want to buy, go through the check-out steps, and you’ll get a confirmation email from us with information and a link to the relevant Early Access courses.

What is Early Access? Chevron down icon Chevron up icon

Keeping up to date with the latest technology is difficult; new versions, new frameworks, new techniques. This feature gives you a head-start to our content, as it's being created. With Early Access you'll receive each chapter as it's written, and get regular updates throughout the product's development, as well as the final course as soon as it's ready.We created Early Access as a means of giving you the information you need, as soon as it's available. As we go through the process of developing a course, 99% of it can be ready but we can't publish until that last 1% falls in to place. Early Access helps to unlock the potential of our content early, to help you start your learning when you need it most. You not only get access to every chapter as it's delivered, edited, and updated, but you'll also get the finalized, DRM-free product to download in any format you want when it's published. As a member of Packt, you'll also be eligible for our exclusive offers, including a free course every day, and discounts on new and popular titles.