Wiki

touch userdata

Introduction

Codea's in-app reference documents most of the touch userdata. The userdata value represents read only data about a single touch on the viewer.

Getting information about a touch

Indexing can be used to get information about a touch, as summarised in the table below:

Index	Comment
id	a number representing a unique identifier for the touch
x	the x position of the touch on the viewer
y	the y position of the touch on the viewer
prevX	the x position of the touch on the viewer, in the previous frame
prevY	the y position of the touch on the viewer, in the previous frame
deltaX	the change in the x position of the touch, since the previous frame
deltaY	the change in the y position of the touch, since the previous frame
state	a number representing the state of the touch
tapCount	a number representing the number of times the touch has been tapped

touch.state

The state of a touch can be one of the following:

state	Global variable	Comment
0	`BEGAN`	Reported once when the viewer is touched.
1	`MOVING`	Reported each time the touch moves on the surface of the viewer.
2	`ENDED`	Reported once when touch leaves the viewer.

touch.tapCount

In some cases, the touch.id is preserved between taps. In other cases, each tap has a distinct touch.id but the touch.tapCount increases with each tap.

In some cases, where touch.state is ENDED, the touch.tapCount is zeroed. In other cases, the touch.tapCount is equal to what it was before the touch.state was ENDED.

Functions

The userdata supports tostring() to produce nicely-formatted output. Consequently, print() also generates nicely-formatted output.