User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:108.0) Gecko/20100101 Firefox/108.0
Firefox for Android

Steps to reproduce:

Taking screenshots of whole page doesn`t work on all websites with a scroll bar ,ex : Chatgpt , this happened on other websites before as well.

Actual results:

when selecting "Whole page" , Firefox only screenshots the current view instead of scrolling down to get a complete screenshot

Expected results:

Firefox should screenshot the whole page

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.

(In reply to scream_abd12 from comment #0)

Actual results:
when selecting "Whole page" , Firefox only screenshots the current view instead of scrolling down to get a complete screenshot

There is a limit to how long a page Firefox will capture. But it is quite long (about 30,000 pixels) and adequate for most purposes. So I'm not sure if you are running into that limit or if something else is going on. It might also be that the page in question uses an iframe and Firefox is only capturing the full length of the top level document, and not scrolling the inner iframe where the content you are looking for is housed?

if you can provide an example URL and/or screenshot we can figure out if there's some actionable bug to fix here.

(In reply to Sam Foster [:sfoster] (he/him) from comment #2)

(In reply to scream_abd12 from comment #0)

Actual results:
when selecting "Whole page" , Firefox only screenshots the current view instead of scrolling down to get a complete screenshot

There is a limit to how long a page Firefox will capture. But it is quite long (about 30,000 pixels) and adequate for most purposes. So I'm not sure if you are running into that limit or if something else is going on. It might also be that the page in question uses an iframe and Firefox is only capturing the full length of the top level document, and not scrolling the inner iframe where the content you are looking for is housed?

if you can provide an example URL and/or screenshot we can figure out if there's some actionable bug to fix here.

I posted on Reddit asking for help with this issue but they directed me here. Like I said when I try to take a screenshot of whole page on Chatgpt , it only screenshot the current view , so as you said , it probably has to do with the document level , I am not really knowledgeable much about Web Design, so forgive my lousy naming. :) . it also happens when I try to screenshot PDFs , it only takes the current view. These are the only two examples I remember for now. But if you can go to CHatgpt and start any conversation with it , until a scroll bar appears, then try to screenshot the whole conversation , you will easily see what happens.
I guess this is not a bug then, but is there a workaround ? I use this tool a lot everyday and if I could get it to work properly in this situation , it will save me a lot of time .
I attached a screenshot ,but I am not sure if you can tell what the problem is from it.

I cannot log into Chat GPT because it appears to be "at capacity", however, the screenshot shows that only the current view is shown after the screenshot. I can confirm this issue based on the screenshot.
Moreover, I've also tried screenshotting a random PDF to get the same result; the screenshot only shows the current view.

I do not know if this can be improved, but I confirm this report as an enhancement.

Encountered similar behavior when trying to take a full screenshot of a random reddit page. Firefox produces a screenshot of the whole page, but it's partially blank, and partially does not display the feed as expected.

Just wanted to confirm if we should perhaps mark this as a defect? From what I can see from a quick test, screenshot tool produces "as expected" screenshots of some pages (under 30k px) and some pdfs for me, and struggles in other circumstances.

I'm not sure if the problem with whole-page capture of PDF is the same issue. Similar symptoms but could be a different underlying problem - can you file a separate bug for that? I don't see an existing bug on file for it.

Encountered similar behavior when trying to take a full screenshot of a random reddit page. Firefox produces a screenshot of the whole page, but it's partially blank, and partially does not display the feed as expected.

This sounds like bug 1812202, can you confirm that describes the issue you are seeing?

Reddit seems to use a virtual list kind of arrangement, where content is loaded as you scroll down the page. So the full page screenshot will only capture whatever content is already loaded - it doesn't actually scroll down to the end of page for you (which is good, as its possible there is no end to the page if you do this.)

I can't get back into ChatGPT to test the other issues, but as I mentioned in comment #2 its likely they are using an i-frame or similar arrangment where the document's scrollbar is hidden and the inner element scrolls. That would be bug 1643719 if so.

So I'm still trying to narrow down on what "can't take a screenshot of the whole page always" means. If the issues described here are already on file we can dupe this bug and close it. If there some aspect that isn't already tracked I'm happy to keep this on file with steps-to-reproduce so we can give it a priority and get it into our backlog.

(In reply to scream_abd12 from comment #4)

I guess this is not a bug then, but is there a workaround ? I use this tool a lot everyday and if I could get it to work properly in this situation , it will save me a lot of time .

No, it is a bug, its just that we already have something on file where we are tracking it and planning how to resolve it. These are bug 1670270 and bug 1643719. One workaround would be to use the newer, in-progress implementation by enabling the screenshots.browser.component.enabled pref in about:config, and use the drag handles to create the selection you want to capture, rather than the "full page" button. That will let you scroll, adjust the rectangle, scroll some more etc.

(In reply to Sam Foster [:sfoster] (he/him) from comment #10)

(In reply to scream_abd12 from comment #4)

I guess this is not a bug then, but is there a workaround ? I use this tool a lot everyday and if I could get it to work properly in this situation , it will save me a lot of time .

No, it is a bug, its just that we already have something on file where we are tracking it and planning how to resolve it. These are bug 1670270 and bug 1643719. One workaround would be to use the newer, in-progress implementation by enabling the screenshots.browser.component.enabled pref in about:config, and use the drag handles to create the selection you want to capture, rather than the "full page" button. That will let you scroll, adjust the rectangle, scroll some more etc.

yes exactly these two bugs, hopefully they get fixed soon :) , I tried your suggestion but I could not scroll after the selection window appears when I tried it on Chatgpt , however it worked on Reddit.
note: if Chatgpt keeps saying "at capacity" just keep refreshing and you should be able to login

(In reply to Sam Foster [:sfoster] (he/him) from comment #10)

One workaround would be to use the newer, in-progress implementation by enabling the screenshots.browser.component.enabled pref in about:config, and use the drag handles to create the selection you want to capture, rather than the "full page" button.

Thinking about it some more, this isn't going to work with an fixed height, overflow: scroll element. The drag handles for the region selection UI are drawn on an overlay that uses the document's top/left corner as origin, so without some work we just don't currently have a way to draw a box on an overflowed element. And even if we did, the captureTab API we use is also rooted on the document and wouldn't capture the overflowed part of the element.

I'm going to dupe this to bug 1643719 where we'll start to explore potential solutions. That seems to cover what is described in comment #0. If you think some aspect of the problem you've seen isn't covered there, feel free to open a new bug for that part. Thanks again for the help, this is a bit of a gnarly problem but it comes up often enough that I think we'll need to find a solution.

:ania, I'm clearing the need-info for :dbodea. I think the pdfjs case might still warrent its own bug. We have a couple PDF-related screenshots bugs on file but none that I could see at a glance that cover an incomplete output problem.

Sam, I filed a standalone bug for the issue that I have with a whole page screenshot on reddit - https://bugzilla.mozilla.org/show_bug.cgi?id=1818114. It's slightly different than the transparent pixels issue.