Closed Bug 990904 Opened 10 years ago Closed 9 years ago

Ensure subframes with background-attachment:fixed scroll properly

Categories

(Core :: Panning and Zooming, defect)

Product:
Core
Component:
Panning and Zooming
Platform:
All
Gonk (Firefox OS)
Type:
defect
Priority:
Not set
Severity:
normal

Tracking

()

Status:
RESOLVED DUPLICATE of bug 1166301

People

(Reporter: kats, Unassigned)

References

(
URL
)

Details

There are going to be cases where we can't do async scrolling for elements. An example is a subframe that has background-attachment:fixed (so says :mstange).

For scrolling these elements based on touch input we need to keep the panning code that currently resides in BrowserElementPanning.js. The best way to do this is to move it into gecko c++ code and have it live alongside the mouse and keyboard pan-driving code.
Summary: Move synchronous panning code into gecko from BrowserElementPanning.js → Move synchronous panning code from BrowserElementPanning.js into C++
Markus, can you provide a test case that you think requires sync scrolling? I tried writing one (http://people.mozilla.org/~kgupta/bug/990904.html) but it does scroll async so I'm not sure I understood the scenario you mentioned.
Flags: needinfo?(mstange)
tn helped me out on IRC. Bug URL has a working test case. Currently we do async scrolling on it, but the background jitters as it repaints, because we don't keep it fixed while scrolling async.
URL: http://people.mozilla.org/~kgupta/bug...
Flags: needinfo?(mstange)
I wonder if we should wait until bug 950934 is fixed before doing this. That would have the effect of going from this sync-scrolling code having to work for all scroll frames, to it having to work for just these pathological cases - that might allow simplifying the code.
If we do need sync-scrolling to handle this case we should use the existing sync scrolling codepath, where the APZ operates on a dummy layer and then dispatches repaint requests to gecko. The panning code in BrowserElementPanning.js should die.
No longer blocks: 970125
Summary: Move synchronous panning code from BrowserElementPanning.js into C++ → Ensure subframes with background-attachment:fixed scroll properly
(In reply to Kartikaya Gupta (email:kats@mozilla.com) from comment #0)
> There are going to be cases where we can't do async scrolling for elements.
> An example is a subframe that has background-attachment:fixed (so says
> :mstange).

As of bug 1166301, we can async-scroll subframes that have background-attachment:fixed!
Status: NEW → RESOLVED
Closed: 9 years ago
Resolution: --- → DUPLICATE
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