Take a screenshot via a Python script on Linux

Question

I want to take a screenshot via a python script and unobtrusively save it.

I\'m only interested in the Linux solution, and should support any X based environment.

Answer 1

for ubuntu this work for me, you can take a screenshot of select window with this:

import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gdk
from gi.repository import GdkPixbuf
import numpy as np
from Xlib.display import Display

#define the window name
window_name = 'Spotify'

#define xid of your select 'window'
def locate_window(stack,window):
    disp = Display()
    NET_WM_NAME = disp.intern_atom('_NET_WM_NAME')
    WM_NAME = disp.intern_atom('WM_NAME') 
    name= []
    for i, w in enumerate(stack):
        win_id =w.get_xid()
        window_obj = disp.create_resource_object('window', win_id)
        for atom in (NET_WM_NAME, WM_NAME):
            window_name=window_obj.get_full_property(atom, 0)
            name.append(window_name.value)
    for l in range(len(stack)):
        if(name[2*l]==window):
            return stack[l]

window = Gdk.get_default_root_window()
screen = window.get_screen()
stack = screen.get_window_stack()
myselectwindow = locate_window(stack,window_name)
img_pixbuf = Gdk.pixbuf_get_from_window(myselectwindow,*myselectwindow.get_geometry()) 

to transform pixbuf into array

def pixbuf_to_array(p):
    w,h,c,r=(p.get_width(), p.get_height(), p.get_n_channels(), p.get_rowstride())
    assert p.get_colorspace() == GdkPixbuf.Colorspace.RGB
    assert p.get_bits_per_sample() == 8
    if  p.get_has_alpha():
        assert c == 4
    else:
        assert c == 3
    assert r >= w * c
    a=np.frombuffer(p.get_pixels(),dtype=np.uint8)
    if a.shape[0] == w*c*h:
        return a.reshape( (h, w, c) )
    else:
        b=np.zeros((h,w*c),'uint8')
        for j in range(h):
            b[j,:]=a[r*j:r*j+w*c]
        return b.reshape( (h, w, c) )

beauty_print = pixbuf_to_array(img_pixbuf)

Answer 2

Try it:

#!/usr/bin/python

import gtk.gdk
import time
import random
import socket
import fcntl
import struct
import getpass
import os
import paramiko     

while 1:
    # generate a random time between 120 and 300 sec
    random_time = random.randrange(20,25)
    # wait between 120 and 300 seconds (or between 2 and 5 minutes) 

    print "Next picture in: %.2f minutes" % (float(random_time) / 60)

    time.sleep(random_time)
    w = gtk.gdk.get_default_root_window()   
    sz = w.get_size()
    print "The size of the window is %d x %d" % sz
    pb = gtk.gdk.Pixbuf(gtk.gdk.COLORSPACE_RGB,False,8,sz[0],sz[1])
    pb = pb.get_from_drawable(w,w.get_colormap(),0,0,0,0,sz[0],sz[1])
    ts = time.asctime( time.localtime(time.time()) )
    date = time.strftime("%d-%m-%Y")
    timer = time.strftime("%I:%M:%S%p")
    filename = timer
    filename += ".png"

    if (pb != None):
        username = getpass.getuser() #Get username
        newpath = r'screenshots/'+username+'/'+date #screenshot save path
        if not os.path.exists(newpath): os.makedirs(newpath)
        saveas = os.path.join(newpath,filename)
        print saveas
        pb.save(saveas,"png")
    else:
        print "Unable to get the screenshot."

Answer 3

There is a python package for this Autopy

The bitmap module can to screen grabbing (bitmap.capture_screen) It is multiplateform (Windows, Linux, Osx).

Answer 4

This works without having to use scrot or ImageMagick.

import gtk.gdk

w = gtk.gdk.get_default_root_window()
sz = w.get_size()
print "The size of the window is %d x %d" % sz
pb = gtk.gdk.Pixbuf(gtk.gdk.COLORSPACE_RGB,False,8,sz[0],sz[1])
pb = pb.get_from_drawable(w,w.get_colormap(),0,0,0,0,sz[0],sz[1])
if (pb != None):
    pb.save("screenshot.png","png")
    print "Screenshot saved to screenshot.png."
else:
    print "Unable to get the screenshot."

Borrowed from http://ubuntuforums.org/showpost.php?p=2681009&postcount=5

Answer 5

import ImageGrab
img = ImageGrab.grab()
img.save('test.jpg','JPEG')

this requires Python Imaging Library

Answer 6

Just for completeness: Xlib - But it's somewhat slow when capturing the whole screen:

from Xlib import display, X
import Image #PIL

W,H = 200,200
dsp = display.Display()
root = dsp.screen().root
raw = root.get_image(0, 0, W,H, X.ZPixmap, 0xffffffff)
image = Image.fromstring("RGB", (W, H), raw.data, "raw", "BGRX")
image.show()

One could try to trow some types in the bottleneck-files in PyXlib, and then compile it using Cython. That could increase the speed a bit.

---

Edit: We can write the core of the function in C, and then use it in python from ctypes, here is something I hacked together:

#include <stdio.h>
#include <X11/X.h>
#include <X11/Xlib.h>
//Compile hint: gcc -shared -O3 -lX11 -fPIC -Wl,-soname,prtscn -o prtscn.so prtscn.c

void getScreen(const int, const int, const int, const int, unsigned char *);
void getScreen(const int xx,const int yy,const int W, const int H, /*out*/ unsigned char * data) 
{
   Display *display = XOpenDisplay(NULL);
   Window root = DefaultRootWindow(display);

   XImage *image = XGetImage(display,root, xx,yy, W,H, AllPlanes, ZPixmap);

   unsigned long red_mask   = image->red_mask;
   unsigned long green_mask = image->green_mask;
   unsigned long blue_mask  = image->blue_mask;
   int x, y;
   int ii = 0;
   for (y = 0; y < H; y++) {
       for (x = 0; x < W; x++) {
         unsigned long pixel = XGetPixel(image,x,y);
         unsigned char blue  = (pixel & blue_mask);
         unsigned char green = (pixel & green_mask) >> 8;
         unsigned char red   = (pixel & red_mask) >> 16;

         data[ii + 2] = blue;
         data[ii + 1] = green;
         data[ii + 0] = red;
         ii += 3;
      }
   }
   XDestroyImage(image);
   XDestroyWindow(display, root);
   XCloseDisplay(display);
}

And then the python-file:

import ctypes
import os
from PIL import Image

LibName = 'prtscn.so'
AbsLibPath = os.path.dirname(os.path.abspath(__file__)) + os.path.sep + LibName
grab = ctypes.CDLL(AbsLibPath)

def grab_screen(x1,y1,x2,y2):
    w, h = x2-x1, y2-y1
    size = w * h
    objlength = size * 3

    grab.getScreen.argtypes = []
    result = (ctypes.c_ubyte*objlength)()

    grab.getScreen(x1,y1, w, h, result)
    return Image.frombuffer('RGB', (w, h), result, 'raw', 'RGB', 0, 1)

if __name__ == '__main__':
  im = grab_screen(0,0,1440,900)
  im.show()