Fire a pinch in/out command to Android phone using adb

So far I'm able to tap, swipe, unlock, install/uninstall and launch app using adb commands but not able to find how to perform zoom in/out using adb command.

I have got coordinates of pinch in/out but not understanding how to fire them using adb command from terminal.

For example , we have command --> adb shell input tap x y So in this we can replace x and y with values/coordinates similarly I want to know the way to simulate pinch in/out.

Coordinates that I get for pinch-in are below.

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Solution

You can do it using adb getevent and sendevent.
Connect you device using adb. Follow the steps below.

Identify your Input device:
Open any image on your device. To list input devices, run

$ adb shell getevent   
add device 1: /dev/input/event7   
name:     "msm8226-tapan9302-snd-card Headset Jack"
add device 2: /dev/input/event6
  name:     "msm8226-tapan9302-snd-card Button Jack"
add device 3: /dev/input/event2
  name:     "synaptics_dsx_i2c"
add device 4: /dev/input/event4
  name:     "qpnp_pon"

Pinch in/out on the image, you should see some continuous logs like

/dev/input/event2: 0003 0030 00000005
/dev/input/event2: 0000 0000 00000000
/dev/input/event2: 0003 002f 00000000
/dev/input/event2: 0003 0036 00000144
/dev/input/event2: 0003 003a 00000079
/dev/input/event2: 0000 0000 00000000
/dev/input/event2: 0003 0036 00000142

Confirms /dev/input/event2 is the input device name for my target device.

Get exact getevent and convert getevent to sendevent:

Make sure your screen switched on and is open with some image,
Run the below command on the prompt.
```
$ adb shell getevent | grep dev/input/event2 > getevent_input.txt
```
While the above is running, Pinch in/out on the image on your phone.

Once completed, Kill the above command Ctrl + C
Open file getevent_input.txt and delete first line "add device X: /dev/input/eventX" from it.

Since getevent returns values in decimal, and sendevent takes value in hexadecimal.
We have to do the above conversion.
This script hex_to_dec.py here does the Job. Thanks to this guy!
```
$./hex_to_dec.py  getevent_input.txt 
```
Generates a file getevent_input.scr, Now rename this file to .sh
```
$ mv getevent_input.scr  sendevent_input.sh
```
Open file sendevent_input.sh and delete second line "echoing – drawing function" and save it.

Run on device.
Transfer sendevent_input.sh to device.

$ adb push sendevent_input.sh /sdcard/
1615 KB/s (64379 bytes in 0.038s)

Make sure you device has an image open, and screen is not off.

$ adb shell sh /sdcard/sendevent_input.sh

Worked perfectly fine for me, If this what you looking for.
For visible results, enable Show touches in Developer Options.

Environment: Motorola Moto G (Android 4.4.4) with ADB (v 1.0.31) on Ubuntu 12.04.