598575 - Scroll redraw on print preview is off by one line of pixels (triggering dark horizontal lines)

Status: RESOLVED FIXED

(Core :: Print Preview, defect)

Description

[Mikko Rantalainen]

User-Agent:       Mozilla/5.0 (X11; Linux x86_64; rv:2.0b7pre) Gecko/20100921 Firefox/4.0b7pre
Build Identifier: Mozilla/5.0 (X11; Linux x86_64; rv:2.0b7pre) Gecko/20100921 Firefox/4.0b7pre

The print preview is missing redraw of one line of pixels when scrolling up or down. The missing line seems to depend on number of pixels scrolled at a time and sometimes all the pixels are correctly rendered.

Reproducible: Sometimes

Steps to Reproduce:
1. Open any long web page (multiple pages if printed on paper)
2. Select File - Print preview
3. Scroll the document downwards (scroll bar, mouse wheel and middle mouse button auto scroll all expose the problem)
Actual Results:  
The pages previewed scroll ok but every now and then a single line of pixels misses the rendering (a horizontal line with background grey appears on the content area). Resizing the window (forcing the redraw) fixes the display.

Expected Results:  
The display should scroll without flaws.

It seems that if content should be scrolled e.g. 15 pixels upwards, the content is blitted 15 pixels upwards but only 14 pixels of actual content are redrawn at the bottom. Only the background is drawn for the (missing) last line of pixels.

I'm running with MOZ_ACCELERATED=11 environment and layers.accelerate-all set to true. The scrolling defect does not appear in normal content (HTML page display as opposed print preview).

Comment 1

[Mikko Rantalainen]

Attachment: Screenshot of the erratic display

Comment 2

[Ilja Sekler]

The intervals between lines are always 4 scroll increments.

Comment 3

[Timothy Nikkel (:tnikkel)]

Does it still happen if you turn off acceleration?

Comment 4

[Ilja Sekler]

(In reply to comment #3)
> Does it still happen if you turn off acceleration?

Yes (SourceStamp=71e8b5aee972).

Comment 5

[Timothy Nikkel (:tnikkel)]

Regression range:
http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=dc2939f2640d&tochange=4b879b793eb6

Comment 6

[Timothy Nikkel (:tnikkel)]

The first bad revision is:
changeset:   51957:c888cdffd617
user:        Robert O'Callahan <[e-mail]>
date:        Fri Sep 03 14:31:42 2010 +1200
summary:     Bug 579276. Part 12: Clip all drawing to the visible region on the nonretained path. r=cjones

Comment 8

[Chris B.]

I see this in the current nightly and am not using Linux, but Windows 7 64-Bit.

Comment 9

[Chris B.]

Attachment: Screenshot of the erratic display - Windows 7 - Current Nightly

Comment 10

[Timothy Nikkel (:tnikkel)]

Random guess: bug 615794 might help here.

Comment 11

[Timothy Nikkel (:tnikkel)]

Something in roc's huge patch queue fixes it for me on Linux (could be bug 615794 or something else).

Comment 12

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

So is this fixed now?

Comment 13

[Chris B.]

I don't know, David.  It hasn't been officially closed yet, but I am not seeing this issue in the current Minefield (1/6/11 Build).

Comment 14

[Ilja Sekler]

(In reply to comment #12)
> So is this fixed now?

Can't reproduce the issue with Firefox 4.0b0pre built from <http://hg.mozilla.org/mozilla-central/rev/efad321b7a2e> on Linux too, so this is likely fixed.

Comment 15

[Daniel Holbert [:dholbert]]

WORKSFORME too with today's nightly:
Mozilla/5.0 (X11; Linux x86_64; rv:2.0b9pre) Gecko/20110106 Firefox/4.0b9pre

Resolving WORKSFORME - we can change that to FIXED if we determine what fixed it.

Comment 16

[Timothy Nikkel (:tnikkel)]

Pretty sure its bug 615794 that fixed this. I tested just before that landed and it wasn't fixed.

Comment 17

[Ilja Sekler]

(In reply to comment #16)
> Pretty sure its bug 615794 that fixed this. I tested just before that landed
> and it wasn't fixed.

If it matters, <http://hg.mozilla.org/mozilla-central/rev/a955dcb369f6> alone fixed the issue. Verified by backout of all parts of bug 615794 and comparing to a build with only part 1 reapplied.

SourceStamp=df3c1150dd7a