Can we Zoom the browser window in python selenium webdriver?

As you mentioned that Need it to work in Chrome. The current solutions are only for Firefox, here are a few updates and options :

1. Zoom the CSS :

   driver.execute_script("document.body.style.zoom='150%'")
   

   This option did work for me. But it zooms the CSS, not the Chrome Browser. So probably you are not looking at that.

2. Zoom In & Zoom Out the Chrome Browser :

After 4131, 4133 and 1621 the fullscreen() mode got supported to Zoom In through Selenium-Java Clients but it’s not yet publicly released to PyPI.

I can see it’s implemented but not pushed. Selenium 3.7 (Python) will be out soon. The push to sync version numbers will include that.

3. Configure the webdriver to open the Browser :

If your requirement is to execute the Test Suite in Full Screen mode, you can always use the Options Class and configure the webdriver instance with --kiosk argument as follows:

from selenium import webdriver
from selenium.webdriver.chrome.options import Options

options = Options()
options.add_argument("--kiosk")
driver = webdriver.Chrome(chrome_options=options, executable_path=r'C:UtilityBrowserDriverschromedriver.exe')
driver.get('https://www.google.co.in')

Yes, you can invoke the Chrome driver to zoom without having to use CSS. There are methods packaged into the Chrome DevTools Protocol Viewer, one being Input.synthesizePinchGesture aka zoom in/out.

For ease of use, with regards to the DevTools Protocol API, we will use a class called MyChromeDriver with webdriver.Chrome as a metaclass and a new method for sending these commands to Chrome:

# selenium
from selenium import webdriver
# json
import json

class MyChromeDriver(webdriver.Chrome):
    def send_cmd(self, cmd, params):
        resource = "/session/%s/chromium/send_command_and_get_result" % self.session_id
        url = self.command_executor._url + resource
        body = json.dumps({'cmd':cmd, 'params': params})
        response = self.command_executor._request('POST', url, body)
        return response.get('value')

1. Setup our webdriver and get some page:

webdriver = MyChromeDriver()
webdriver.get("https://google.com")

2. Send Chrome the Input.synthesizePinchGesture command along with its parameters via our new method send_cmd:

webdriver.send_cmd('Input.synthesizePinchGesture', {
                        'x': 0,
                        'y': 0,
                        'scaleFactor': 2,
                        'relativeSpeed': 800, # optional
                        'gestureSourceType': 'default' # optional
                    })

3. Walla! Chrome’s zoom is invoked:

As a side note, there are tons of other commands you could use with send_cmd. Find them here: https://chromedevtools.github.io/devtools-protocol/

Based off this answer: Take full page screen shot in Chrome with Selenium

Environment:

• Selenium 3.6.0
• chromedriver 2.33
• Chrome version 62.0.3202.75 (Official Build) (64-bit)
• macOS Sierra 10.12.6

I tried the ways (without use the CSS) that people suggested in other questions in the past. For example, the answers in this question: Selenium webdriver zoom in/out page content.

Or this: Test zoom levels of page on browsers

without success.

So, I thought: if not with the shortcuts, what could be a different way to do that?

The idea is to use the "chrome://settings/" page in order to change the zoom:

Ok I know, for example from Going through Chrome://settings by Selenium, that every settings should be set in the ChromeOptions.

From this question I noticed that in the list of preferences the only paramater (I think) could be:

// Double that indicates the default zoom level.
const char kPartitionDefaultZoomLevel[] = "partition.default_zoom_level";

I tried, without success.

I want to repeat that I know it isn’t the correct approach (and that will be different with different browser versions), but it works and, at least, was useful for me to understand how to go inside a shadow root element with selenium.

The following method return the elements inside a shadow root:

def expand_shadow_element(element):
    shadow_root = driver.execute_script('return arguments[0].shadowRoot', element)
    return shadow_root

It is useful because in the chrome://settings/ page there are shadow root elements.

In order to do that in my browser, this is the path:

root1=driver.find_element_by_xpath("*//settings-ui")
shadow_root1 = expand_shadow_element(root1)
container= shadow_root1.find_element_by_id("container")

root2= container.find_element_by_css_selector("settings-main")
shadow_root2 = expand_shadow_element(root2)

root3=shadow_root2.find_element_by_css_selector("settings-basic-page")

shadow_root3 = expand_shadow_element(root3)
basic_page = shadow_root3.find_element_by_id("basicPage")

settings_section= basic_page.find_element_by_xpath(".//settings-section[@section='appearance']")

root4= settings_section.find_element_by_css_selector("settings-appearance-page")
shadow_root4=expand_shadow_element(root4)

and finally:

settings_animated_pages= shadow_root4.find_element_by_id("pages")
neon_animatable=settings_animated_pages.find_element_by_css_selector("neon-animatable")

zoomLevel= neon_animatable.find_element_by_xpath(".//select[@id='zoomLevel']/option[@value='0.5']")
zoomLevel.click()

The entire code:

driver = webdriver.Chrome(executable_path=r'/pathTo/chromedriver')

def expand_shadow_element(element):
    shadow_root = driver.execute_script('return arguments[0].shadowRoot', element)
    return shadow_root


driver.get('chrome://settings/')

root1=driver.find_element_by_xpath("*//settings-ui")
shadow_root1 = expand_shadow_element(root1)
container= shadow_root1.find_element_by_id("container")

root2= container.find_element_by_css_selector("settings-main")
shadow_root2 = expand_shadow_element(root2)

root3=shadow_root2.find_element_by_css_selector("settings-basic-page")

shadow_root3 = expand_shadow_element(root3)
basic_page = shadow_root3.find_element_by_id("basicPage")

settings_section= basic_page.find_element_by_xpath(".//settings-section[@section='appearance']")

root4= settings_section.find_element_by_css_selector("settings-appearance-page")
shadow_root4=expand_shadow_element(root4)

settings_animated_pages= shadow_root4.find_element_by_id("pages")
neon_animatable=settings_animated_pages.find_element_by_css_selector("neon-animatable")

zoomLevel= neon_animatable.find_element_by_xpath(".//select[@id='zoomLevel']/option[@value='0.5']")
zoomLevel.click()


driver.get("https://www.google.co.uk/")

EDIT

As suggested by @Florent B in the comments, we can obtain the same result simple with:

driver.get('chrome://settings/')
driver.execute_script('chrome.settingsPrivate.setDefaultZoom(1.5);')
driver.get("https://www.google.co.uk/")

firefox solution for me,

Zoom body browser

zoom is a non-standard property, use transform instead (demo):

driver.execute_script("document.body.style.transform = 'scale(0.8)'")

https://github.com/SeleniumHQ/selenium/issues/4244

driver.execute_script('document.body.style.MozTransform = "scale(0.50)";')

driver.execute_script('document.body.style.MozTransformOrigin = "0 0";')

# zoom in firefox browser
driver.get("about:preferences")
driver.execute_script("arguments[0].click();", driver.find_element(By.XPATH, "// [@id='defaultZoom']"))
ActionChains(driver).click(driver.find_element(By.XPATH, "//*[@value='50']")).perform()