Sunday, February 19, 2017

How-To implement 2 finger pan gesture in Delphi Firemonkey

In Firemonkey, as you know, there is a great support for gestures: standard and interactive. The most important interactive gestures as Zoom, Pan, Rotate, DoubleTap (with an amazing description in dockwiki ), etc... are provided by the framework. See here for a full documentation. In a recent project I had the need to implement 2 finger pan gesture, that is not present in the provided gestures. But Firemonkey is a very great framework, and you can implement an event handler to manage custom actions when OnTouch occurs to specify what happens when a user touches the form using a finger or a similar device (not a mouse). So I wrote a little snippet of code that simulate the 2 finger pan gesture, I created a new demo and moved it into my Delphi Demos repository on Github.
I tried it on Android and works fine and very smoothly. It should works fine on all Firemonkey supported platforms: Windows, Android, iOS and OSX.