Take advantage of built in support for full page screenshots

[nextlevelbeard]

Is your feature request related to a problem? Please describe.
Often, the full page screenshots are unreliable and contain ghosting of elements due to scrolling effects.
For example: see #125

Describe the solution you'd like
Multiple browsers have built in support for this that deliver a clean and ghost free image.

For Firefox, we can create a client side script that calls the :screenshot command. See docs here:
https://firefox-source-docs.mozilla.org/devtools-user/taking_screenshots/index.html#taking-screenshots-with-the-web-console

Then execute it with the executor function in getFullPageScreenshotsDataDesktop:

visual-testing/packages/webdriver-image-comparison/src/methods/screenshots.ts

Line 352 in b40be9d

export async function getFullPageScreenshotsDataDesktop(

Describe alternatives you've considered

We could also call the webdriverIO API: browser.fullPageScreenshot(), if the browser is available to us.
https://webdriver.io/docs/api/gecko/#fullpagescreenshot

[christian-bromann]

We should update the saveScreenshot command in WebdriverIO core to use WebDriver Bidi primitives for taking screenshots. They provide full flexibility including full page screenshots.

[wswebcreation]

Thanks for your FR @nextlevelbeard , I've investigated the Firefox one in the past and wasn't fully reliable. But I can do a research again

@christian-bromann That would be great! Adding a flag for fullpage might be very useful

[nextlevelbeard]

@wswebcreation @christian-bromann

Am I correct to say that this is now unblocked by PR webdriverio/webdriverio#14267 being merged and released with webdriverIO v9.12.0 ?

[wswebcreation]

@nextlevelbeard

Yes, you are correct, but....., there is a "hard dependency" with using the correct version of the webdriverio package. Just checking if it's BiDi is not enough. For now, the module doesn't know which webdriverio version the user uses.
The project-committers are now looking for a good solution that is not only usable for the visual package, but also for future packages/modules