Finding items by their position

The Canvas class includes methods to retrieve item identifiers that are close to a canvas coordinate.

This is very useful because it saves us from storing each reference to a canvas item and then calculating their current position to detect which ones are within a specific area or closest to a certain point.

Getting ready

The following application creates a canvas with four rectangles, and changes the color of the one that is closest to the mouse pointer:

How to do it...

To find the closest item to the pointer, we pass the mouse event coordinates...