1810934 - Full Page Screenshot breaks after 16400px

Status: RESOLVED DUPLICATE of bug 1743887

(Firefox :: Screenshots, enhancement)

Description

[tusharamit]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36

Steps to reproduce:

If you take a very big page i.e. a webpage having DOM height above > 20000px and take a full page screenshot we can see that the screenshot starts breaking.
Ideally the issue starts occurs at 16383px which is 32767/2.

Load the DOM > Take Full Page SS (cmd + shift + s) > Full Page

Actual results:

Elements above 16k px
Some DOM/CSS elements are missing.
Some CSS starts breaking.

Expected results:

The screenshot should have been same as the DOM is rendered. All elements above 16k should also be consistent.

Comment 1

[tusharamit]

The issue has been occurring for all the firefox versions. I have added a fix on my end on my local side since the max capacity is of 32767px. What I am doing is I am taking 2 screenshots each of 16,383px and merging them on to drawn canvas depending upon the max height required. I looked at memory and other options was not able to debug it. So In order to solve it I ended up writing a code to take 2 screenshots.

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Firefox::Screenshots' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 3

[Ina Popescu, Desktop QA]

Hello tusharamit,
Could you please provide the webpage where you noticed this issue so that we could reproduce it on our side(a webpage having DOM height above > 20000px)?

Comment 4

[tusharamit]

Attachment: dummyLongPage.html

Attached the example DOM with issue. Just open it in chrome and render it to take full page screenshot and it should break. The images appearing black will disappear. Let me know if you need other details as well. These are good to reproduce the issue though.

Comment 5

[Rares Doghi, Desktop QA]

I was also able to reproduce this issue on my side using the Demo page from comment 4, Loading the demo page in Firefox and then saving the full visible page will stop showing the thumbnail images. I will attach the screenshots that I managed to save.

Please note that I could only get these screenshots on a Windows 10 machine because on Mac OSx 11.1 it will return an error saying that Firefox Screenshots went Haywire, without actually saving anything.

I'm not sure if this is an actual defect or if it should be treated as an Enhancement.
Thanks for all the extra info @tusharamit.

Comment 7

[Rares Doghi, Desktop QA]

I was able to verify this fix in our latest Nightly build after flipping the screenshots.browser.component.enabled pref to true in about:config.