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Raspberry Pi 3 Cookbook for Python Programmers - Third Edition
book

Raspberry Pi 3 Cookbook for Python Programmers - Third Edition

by Steven Lawrence Fernandes, Tim Cox
April 2018
Beginner content levelBeginner
552 pages
13h 58m
English
Packt Publishing
Content preview from Raspberry Pi 3 Cookbook for Python Programmers - Third Edition

How it works...

The Python code creates a Tkinter window that contains a Canvas object called the_canvas. We use the bind function here, which will bind a specific event that occurs on this widget (the_canvas) to a specific action or key press. In this case, we bind the <Motion> function of the mouse, plus the click and release of the first mouse button (<ButtonPress-1> and <ButtonRelease-1>). Each of these events are then used to call the mouse1press(), mouse1release(), and mousemove() functions.

The logic here is to track the status of the mouse button using the mouse1press() and mouse1release() functions.

If the mouse button has been clicked, the mousemove() function will check to see whether we are drawing a new line (we set new coordinates ...

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Publisher Resources

ISBN: 9781788629874Supplemental Content