1811925 - Implement scrolling screenshots via ScrollCapture API

Status: RESOLVED DUPLICATE of bug 1530967

(GeckoView :: General, enhancement, P3)

Description

[Jonathan Almeida [:jonalmeida]]

From github: https://github.com/mozilla-mobile/fenix/issues/20905.

What is the user problem or growth opportunity you want to see solved?

Since the first Android 12 beta (DP 1), Google has been polishing the new scrollable screenshots. Now the screenshots are detecting automatically whether the View that we have screenshoted is a scrollable one and the system is presenting us with the option to scroll more in order to extend the screenshot. This is only happening automatically for View-based screenshots and not for web-based (like a browser's webview). The latest Canary version of Chrome has already started to experiment with this link. I know that it's still early to have this change inside Firefox, but the official Android 12 release is almost here, so we have to think of implementing it at some point, or at least to start tinkering with it. Since the fourth beta of Android 12 is already released, we know for sure that this one will be in the final APIs.

ScrollCapture API docs

How do you know that this problem exists today? Why is this important?

Firefox, like many other apps, hasn't implemented (or even started to experiment with) the new ScrollCapture API. It would be good at some point to have this new feature come to Firefox on Android as well.

Who will benefit from it?

All users running Android 12+
It would also help with switching of the users from Chrome to Firefox at some point, since having this feature is a big plus for either browser.

┆Issue is synchronized with this Jira Task

Change performed by the Move to Bugzilla add-on.

Comment 1

[badgooner]

Can this be implemented please? Difficult to recommend Firefox over chrome when Android native features like scrolling screenshot do not work in Firefox.

Comment 2

[jackyzy823]

Attachment: scrollcapture.patch

Comment 3

[jackyzy823]

Attachment: scrollcapture.patch

Comment 4

[jackyzy823]

Hello, i made a draft implementation of scrollcapture.

I'm here to ask some questions and discuss some implementation details.

Questions:

1.Are there any documents to get the accurate definition of some width/height properties?

Currently. I use the properties by "logging it's value" then decide if it is right to use here.
For example, how to get the current document's width/height, how to get devices' width/height and etc...

Discussion

1.Should we 1) capture fullpage first, and return part by part in onScrollCaptureImageRequest , or 2) capture specific area when each onScrollCaptureImageRequest ?

Currently i use the first one as it is easy to implement . However there might be some problems 1) It could use a lot of memory if bitmap is large which could cause OOM 2) ScrollCapture wouldn't use up the full page , it would only capture content of 5~6 times (not very accurately counted) of current device height. so capturing full page is a waste.

use the second one , i guess scaling will cause some problem.

Thanks.

Comment 5

[Jeff Boek [:boek]]

Hey Jackyzy, Going to bring this up in our next triage to see if I can get some of your questions answered!

Comment 6

[Sin Shadow Fox]

Okay, scrolling screenshots recently stopped working for me (the scrolling screenshot button underneath the screenshot no longer appears when taking a screenshot of Firefox pages). What's going on?