This page scrolls slowly in both Nav6 PR 1 and Moz 2000062608 Sorry for not creating a minimal test case.

I don't see this behavior on Win98 using build 062508. Perhaps an NT video driver problem?

Same for me with 061820 on Win98, it "scrolls" about 3 steps per second. Very fast (normal) scrolling with NS 4.72 and IE 5.0.

Trying it on another computer, it seems to be scrolling somewhat normally. One click of the mouse wheel and it scrolls the entire page (But thats another bug). I think its safe to say this was a false alarm.

Reproduced on 2000070508 Win2000, also reproduced in NT4 running in VMware/Linux. Seems to be an NT-only bug. need simple testcase + determine proper component.

Pierre, can you please triage.

It is clearly slow to scroll - and my NT box makes some VM-noise when scrolling too. It is the background image: remove it and the scrolling is brilliant. The image is 5 X 8000 pixels, and it is a GIF, so if this is a bug it should probably go to the imagelib... I'm guessing it is since IE and Nav scroll just fine with the GIF background. I'll attach a local copy of the page since it is easier to cut-up that way.

Page is scrolling slowly when the background image is used. Uncomment out the style rule in the attached copy of the page to set the background to none and it scrolls very fast. Possibly a problem with GIF images of large size?

It seems like MOST pages with background images (not just GIFs) are somewhat or much slower than pages without them. Yet the speed of these pages in IE 5.0, Opera 4.0, and Navigator 4.x is just fine. Some other examples: http://www.nasa.gov http://samandmax.mixnmojo.com/purcellinterview.html Even a page with a moderately sized background image is somewhat slower.. http://www.w3.org/TR/REC-CSS2 Everything should scroll as fast as http://www.mozilla.org does right now.

Don: this sounds like a tiling issue....want to take a look? -p

*** Bug 45538 has been marked as a duplicate of this bug. ***

I can fix this only for NT using the PatBlt code path of background tiling, this will not work for win98 or win95 because the PatBlt call can only be used for small tile sizes (smaller than 8x8 pixels). I will check in the fix when after beta2.

Index: nsRenderingContextWin.cpp =================================================================== RCS file: /cvsroot/mozilla/gfx/src/windows/nsRenderingContextWin.cpp,v retrieving revision 3.118 Patch for fast background rendering on windows NT diff -r3.118 nsRenderingContextWin.cpp 2876c2876 < return PR_FALSE; --- > return PR_TRUE;

Hello, This page scrolls just fine. OS: Win98 Build: 2000072108 Skin: Cool Blue I did notice slow scrolling in Modern skin, but not Cool Blue. Have you tried using Classic?

I have a one line fix for this...

Marked nsbeta3+

http://63.76.44.234/moztest/ is a little test case that illustrates this bug

*** Bug 48001 has been marked as a duplicate of this bug. ***

*** Bug 47766 has been marked as a duplicate of this bug. ***

Is the slow scrolling on http://whirlpool.net.au/ related to this?

These images are very large.. so when it scrolls the entire image gets copied many many times. This can be fixed by limiting the damage rect when scrolling occurs.. but there is another bug that was fixed by bliting the entire image everytime for a background tiling bug Mark Attinasi did. This is a duplicate of that bug.. which I have to find the number for. Anyway.. this probably will not be fixed for this version because to fix that bug we need to do an API change.. and that would be risky.

This occurs with inline images as well. See http://www.wadsack-allen.com/~jwadsack/test1.html on WinNT (M17). When scrolling down the scroll is fine, scroll back up and it shakes when the image comes to the visible region.

This bug is caused by bug 41134. When 41134 is fixed this will go away. *** This bug has been marked as a duplicate of 41134 ***

not a dupe, but rather a depend, reopening and marking depend on 41134

Adding Arch keyword. per dcone 8/9.

I just added a minimal test case to flex this bug. Interesting note: it only occurs for background images that are transparent PNGs. Also specified a BASE HREF to load images off my site. The attachment already contains commented out lines for opaque PNG, and opaque GIF and transparent GIF.

Some types of backgrounds scroll slowly.. and this can not be helped.. some types of transparency (like 8 bit transparent images), 256 color images, etc, etc. The case you mentioned is one of those.

Verified Mr. Cone :-)