This event uses the value data field, which will be the scale factor of the average spacing from all current touch points compared to the spacing of all the old touch points. The scale factor is calculated by newspacing/oldspacing, so a value of 1.1 indicates a growth of 10% and a value of 0.9 indicates a shrink of 10%

Data

uint32_t    button
uint32_t    timestamp
int16_t     subtype
int16_t     x
int16_t     y
int16_t     z
int16_t     id
int16_t     spare
float       value
float       x_move
float       y_move
int16_t     npoints
                    

Where: