1189837 - Print Preview - displayed page contents extend beyond paper sheet edges

Status: RESOLVED FIXED

(Core :: Panning and Zooming, defect)

Description

[dw-dev]

Attachment: Print Preview - page contents extend beyond paper sheet edges

User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:42.0) Gecko/20100101 Firefox/42.0
Build ID: 20150730030208

Steps to reproduce:

File > Print Preview


Actual results:

Print Preview is displayed with page contents extending beyond the paper sheet edges.


Expected results:

Page contents should be truncated at paper sheet left/right margin and (if there are multiple pages) interrupted at paper sheet top/bottom margins.

Comment 1

[Alice0775 White]

[Tracking Requested - why for this release]:

Comment 2

[Alice0775 White]

Pushlog:
https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=738d8ee106fe&tochange=af67b5f73381

Suspect: 59d0d20d6337	Kartikaya Gupta — Bug 1178354 - Ensure we fire a before-first-paint event for printing as well. r=tn

Comment 3

[Kartikaya Gupta (email:[e-mail])]

The patch was supposed to fix issues like this, not create them! *sigh* I'll try to repro and investigate.

Comment 4

[Liz Henry (:lizzard) (relman/hg->git project)]

Tracking for 42. Sounds like kats is on the job :)

Comment 5

[Kartikaya Gupta (email:[e-mail])]

I was able to repro this on my windows machine easily. Turning on paint flashing showed that the extra white areas were not getting repainted. I confirmed that they are coming from the checkerboarding-background-color code in ContainerLayerComposite.cpp by commenting out that code and observing that the white areas went away. I just need to figure out exactly why that code is triggering and how to fix it properly.

Comment 6

[Kartikaya Gupta (email:[e-mail])]

The reason it was checkerboarding is because the composition bounds was a little too large. This in turn was because the composition bounds was subtracting off the scrollbars using CSS pixels instead of LD pixels (i.e. what it says at https://bugzilla.mozilla.org/show_bug.cgi?id=1168487#c0). Correcting that fixed the problem.

Comment 7

[Kartikaya Gupta (email:[e-mail])]

Attachment: Patch

I also verified that this patch has the desired behaviour after full zoom has been applied. (STR: load google.co.uk on a device with 1.5 CSSToLayoutDevice with layer borders, and ctrl+ to apply full zoom, ensure purple border doesn't overlap scrollbar.)

I'm not sure if there is a difference between this and explicitly using UnscaledDevicePixelsPerCSSPixel like you mention in bug 1168487 comment 0 but the end result here seems correct.

Comment 8

[Markus Stange [:mstange]]

Comment on attachment 8643723 [details] [diff] [review]
Patch

Review of attachment 8643723 [details] [diff] [review]:
-----------------------------------------------------------------

This is much better than explicitly using UnscaledDevicePixelsPerCSSPixel.

Comment 9

[Kartikaya Gupta (email:[e-mail])]

Try push: https://treeherder.mozilla.org/#/jobs?repo=try&revision=fbf79cfbcdc0, will land if that's green.

Comment 10

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/fa8ed8cd2a06

Comment 11

[Timothy Nikkel (:tnikkel)]

Comment on attachment 8643723 [details] [diff] [review]
Patch

Hmm, shouldn't we do this for all the users of ScrollbarAreaToExcludeFromCompositionBoundsFor?

Comment 12

[Kartikaya Gupta (email:[e-mail])]

Oh, I thought I did. Missed the use site in MobileViewportManager, but I'll update that too (tomorrow morning).

Comment 13

[Kartikaya Gupta (email:[e-mail])]

I put the patch on bug 1168487, just because I like closing bugs with patches rather than as dupes. :)

Comment 14

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/fa8ed8cd2a06

Comment 16

[dw-dev]

Is this bug fix in Nightly 2015-08-07 ?

The reason for asking is that the display behaviour in print preview has changed from that which I originally reported, but there are now diiferent display artefacts:

- depending on the page displayed and zoom level, there may be a thin horizontal white line displayed in the right-hand background area (e.g. Google home page and 100% zoom).

- depending on the page displayed, zoom level and scroll position, the page contents still sometimes extend beyond the paper sheet edges; if scrolling with the mousewheel, this may be transient.

- in all cases, scrolling up or down using the mousewheel, causes graduated banded shading of the background area on both sides, towards the bottom or top of the window.

Comment 17

[Kartikaya Gupta (email:[e-mail])]

Yes, the bug fix is in Nightly 2015-08-07.

(In reply to dw-dev from comment #16)
> - depending on the page displayed and zoom level, there may be a thin
> horizontal white line displayed in the right-hand background area (e.g.
> Google home page and 100% zoom).
> 
> - depending on the page displayed, zoom level and scroll position, the page
> contents still sometimes extend beyond the paper sheet edges; if scrolling
> with the mousewheel, this may be transient.

Hm, please file new bugs for these issues, and include the URLs on which you are seeing these. Thanks.

> - in all cases, scrolling up or down using the mousewheel, causes graduated
> banded shading of the background area on both sides, towards the bottom or
> top of the window.

This one is bug 1169957.

Comment 18

[dw-dev]

> - depending on the page displayed and zoom level, there may be a thin
> horizontal white line displayed in the right-hand background area (e.g.
> Google home page and 100% zoom).
> 
> - depending on the page displayed, zoom level and scroll position, the page
> contents still sometimes extend beyond the paper sheet edges; if scrolling
> with the mousewheel, this may be transient.

I have only noticed the first problem on the Google home page.  The second problem happens on many web pages.  After looking at quite a lot of URL's in print preview, I am fairly certain that these two problems have the same underlying cause.

I have raised bug 1192498 to cover both problems. 

> - in all cases, scrolling up or down using the mousewheel, causes graduated
> banded shading of the background area on both sides, towards the bottom or
> top of the window.

I have confirmed that disabling apz (layers.async-pan-zoom.enabled = false) eliminates this problem.  I will re-test when bug 1169957 is fixed.