How to limit screenshot height in selenium python?

Question

How to limit screenshot height in selenium python?

I would like to get a screenshot of a full web page with Selenium python. To do that I used this answer.

But now I would like to divide the screenshot and limit the height of the resulting screenshot to 30 000px. For example, if a webpage height is 40 000px, I would like a first 30 000px screenshot and then a 10 000 px screenshot.

The solution should not be to save the full page and then crop the image, because I need it to work for very long webpages. Indeed it is not possible to get a screenshot with 120 000px height or you get this kind of error :

    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.WebDriverException: Message: [Exception... "Failure"  nsresult: "0x80004005 (NS_ERROR_FAILURE)"  location: "JS frame :: chrome://marionette/content/capture.js :: capture.canvas :: line 154"  data: no]

I tried this but it does not wok at all :

from selenium import webdriver
from selenium.webdriver.firefox.options import Options
from time import sleep

def save_screenshot(d, path):
    max_size = 30000
    original_size = d.get_window_size()
    required_width = d.execute_script('return document.body.parentNode.scrollWidth')+74
    required_height = d.execute_script('return document.body.parentNode.scrollHeight')+74
    if required_height <= max_size:
        d.set_window_size(required_width, required_height)
        d.find_element_by_tag_name('body').screenshot(path)  # avoids scrollbar
    else :
        for i in range(0,int(required_height/max_size)):
            d.set_window_position(0,max_size*i)
            d.set_window_size(required_width, max_size)
            d.find_element_by_tag_name('body').screenshot(path.replace(".png",str(i+1)+".png"))
        d.set_window_position(0,max_size*int(required_height/max_size))
        d.set_window_size(required_width, required_height%max_size)
        d.find_element_by_tag_name('body').screenshot(path.replace(".png",str(int(required_height/max_size)+1)+".png"))
        d.set_window_position(0,0)
    d.set_window_size(original_size['width'], original_size['height'])

if __name__ == '__main__':
    options = Options()
    options.headless = True
    driver = webdriver.Firefox(options=options,executable_path=r"C:/Users/path/geckodriver.exe")
    driver.get("http://www.lwb.com/")
    sleep(3)
    save_screenshot(driver,"C:/Users/path/test.png")
    driver.close()

Can someone help me here please ?

Thank you,

Mylha

python

selenium

screenshot

asked on Stack Overflow Apr 27, 2019 by

mylha

1 Answer

you can crop the saved screenshot using pillow pip install pillow

def crop_image(img, img_limit):
    img_width, img_height = img.size
    crop_dim = (0, 0, img_width, img_limit) # left top right bottom
    cropped_img = img.crop(crop_dim)
    return cropped_img

after doing save_screenshot(driver, "path/to/img"), do the following :

from PIL import Image

img_limit = 30000 # your image size limit
img = Image.open("path/to/img")
img = crop_image(img, img_limit)
img.save("path/to/img")

if you don't want to save the image before you manipulate it you can use get_screenshot_as_png, which will return binary data instead of saving it :

from PIL import Image
from io import BytesIO

img_limit = 30000 # your image size limit
img_binary = driver.get_screenshot_as_png()
img = Image.open(BytesIO(img_binary))
img = crop_image(img, img_limit)
img.save("path/to/save")

make sure to do del img and del img_binary when you're done to delete the binary data from memory

in order to take one screenshot of the entire page, do this:

from selenium import webdriver

DRIVER_PATH = "path/to/chrome/driver"
URL = "site.url"

options = webdriver.ChromeOptions()
options.add_argument("headless")
driver  =  webdriver.Chrome(executable_path = DRIVER_PATH, chrome_options = options)

# setting a long window height to take one full screenshot
driver.set_window_size(1920, 90000) # width , height
driver.get(URL)
driver.maximize_window()

img_binary = driver.get_screenshot_as_png()

PS : if you use this method to take the screenshot, you won't need pillow. simply use set_window_size to set the height and width of the window that you want, which will get you that same size in the screenshot

answered on Stack Overflow Apr 27, 2019 by

Mohamed Benkedadra • edited Apr 28, 2019 by

Mohamed Benkedadra

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