get android sendevent coordinates scale factor

Issue

I am trying to write a script to test my application but when I use sendevent the x and y coordinates are wrong. when I check the getevent output I can see that the coordinates are multiplied by 1.65 how do I get this scale factor programmaticly ?

Solution

On my Motorola Defy with CyanogenMod 7.2 (Android 2.3.7) I can get the min and max values for the scanner coordinates returned by the touch device (and for all other event types too) through a call of getevent -p /dev/input/event3:

~ # getevent -p /dev/input/event3
getevent -p /dev/input/event3
add device 1: /dev/input/event3
  name:     "qtouch-touchscreen"
  events:
    SYN (0000): 0000  0001  0003
    KEY (0001): 0066  008b  009e  00d9  0102  014a
    ABS (0003): 0000  value 0, min 21, max 1003, fuzz 0 flat 0
                0001  value 0, min 0, max 941, fuzz 0 flat 0
                0010  value 0, min 21, max 1003, fuzz 0 flat 0
                0011  value 0, min 21, max 1003, fuzz 0 flat 0
                0018  value 0, min 0, max 255, fuzz 2 flat 0
                001c  value 0, min 0, max 20, fuzz 2 flat 0
                0030  value 0, min 0, max 255, fuzz 2 flat 0
                0032  value 0, min 0, max 20, fuzz 2 flat 0
                0035  value 0, min 21, max 1003, fuzz 0 flat 0
                0036  value 0, min 0, max 941, fuzz 0 flat 0

As you can see Defy's min and max values for the coordinates of the scanner (events 0035 & 0036) are xMin=21, xMax=1003, yMin=0, yMax=941.

With these and the given resolution of the screen in pixels, any pixel coordinates can be easily transformed into scanner coordinates. In a shell script this would look like this (screen resolution of Moto Defy = 480 x 854 px):

let xScanner=$(( $xPix * ($xMax-$xMin) / 479 + $xMin ))
let yScanner=$(( $yPix * ($yMax-$yMin) / 853 + $yMin ))

Works perfectly for me.

Answered By - Jpsy