This bug is extracted from bug 68821. Scrolling is very slow when there is a fixed background image. As I wrote in bug 68821 [2001-02-15 04:15], the problem is that a fixed background causes the frame to set the NS_VIEW_PUBLIC_FLAG_DONT_BITBLT on the view, which means that the view is entirely redrawn everytime we scroll. We should instead redraw only the portion of the page that contains the image. See the testcase I attached to the other bug: http://bugzilla.mozilla.org/showattachment.cgi?attach_id=25333 For the bug to be obvious, the page should not be too small.
Currently, the view manager isn't told which part of the view is non-blittable. To track that, we would need an extra rectangle field in each view (or maybe just a pointer since we won't need it often), and we'd have to change the view manager interface so that layout tells us the non-blittable rectangle. This information would have to be updated as the image loads and its size information becomes available. In other words, this would be a real pain.
Setting target milestone to 1.0.1
Target Milestone: --- → mozilla1.0.1
Target Milestone: mozilla1.0.1 → ---
Set milestone to future
Status: NEW → ASSIGNED
Target Milestone: --- → Future
Does the performance drop off dramatically with CPU speed? On 500 Mhz there is no perceptible slowdown on the referenced page.
Can't reproduce this with Mozilla/5.0 (Windows; U; WinNT4.0; en-US; 0.8.1) Gecko/20010412 Scrolling of the attachment mentioned is really fast thanks to the new imglib.
Additional test pages: http://www.physics.hmc.edu/courses/p028/ http://www.w3.org/TR/html401/ The physics lab page scrolls slowly for me on Win98 using Mozilla 2001 042908.
I see visible slowdown on Linux, K6-2 350
less but still visible slowdown on NT4, Celeron 450
bigger slowdown on linux was actually caused by bigger screen resolution
see this on linux,too sould be platform all -> all
I think this is a bad dupe of 90198 (Bugzilla Bug 90198 scrolling very slow (fixed background)), but that bug is assigned to Kevin too! (although I suspect he doesn't know that). And btw like people say above, this is an ALL/ALL bug, really.
Marking dup per xan's comment. *** This bug has been marked as a duplicate of 90198 ***
Status: ASSIGNED → RESOLVED
Last Resolved: 17 years ago
Resolution: --- → DUPLICATE
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