239213 - [UX] Auto-scrolling on some pages in print preview does not work

Status: NEW

(Core :: Print Preview, defect)

Description

[Chris]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.6) Gecko/20040206 Firefox/0.8
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.6) Gecko/20040206 Firefox/0.8

Switching to print preview mode on a page like
http://bugzilla.mozilla.org/enter_bug.cgi?product=Firefox and attempting to
auto-scroll by clicking the center mouse button does not work for certain pages.

Reproducible: Always
Steps to Reproduce:
1. Go to problem URL page
2. File > Print Preview
3. Center click somewhere off the preview to scroll and moving the mouse up and
down from that spot

Actual Results:  
Auto-scroll icon does not appear and page does not scroll as expected

Expected Results:  
Icon should have been shown and page scrolled up or down

Comment 1

[Asa Dotzler [:asa]]

related to bug 239212?

Comment 2

[Andrew Hayden]

I've also noticed this behavior without clicking on anything.  It seems to be a
focus issue.  Moving the mouse to the area outside of the page boundaries makes
scrolling work again if you have not clicked on anything.

Comment 3

[Marcus Campbell]

I reckon this is basically just bug 239212 again, but XP or mouse software might
be allowing limited autoscrolling of the preview.

Comment 4

[Percy Cabello]

Not sure if this is related to this bug:

- In Print preview if I wheel scroll while the mouse cursor is over content or
the gray background of the Print Preview window it scrolls.
- When positioned over the pages' margins, vertical and horizontal, including
the header and the footer, it doesn't. 

Using: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.6) Gecko/20050317
Firefox/1.0.2

Comment 5

[Robin Monks]

Moving to core, taking QA...

Comment 7

[Botond Ballo [:botond]]

Copying over some info that might be relevant from bug 1396028 comment 0:

Autoscrolling has been broken in Print Preview for a while. I disabled it in bug 1393424.

At least two things need to happen before we can re-enable it:

  1) The content-side JS code that initiates autoscrolling uses
     "content.performance.now()" to obtain a timestamp [1], but
     "content.performance" is null in Print Preview. We'll need
     to find another way of getting a timestamp.

  2) There is a coordinate systems problem, tracked in bug 1393424,
     which causes both tooltips and the autoscroll anchor to appear 
     in the wrong location. In the case of autoscrolling, this
     causes unintended scrolling, since scrolling is caused by
     the mouse being away from the autoscroll anchor.

[1] http://searchfox.org/mozilla-central/rev/51b3d67a5ec1758bd2fe7d7b6e75ad6b6b5da223/toolkit/content/browser-content.js#179

Comment 8

[Botond Ballo [:botond]]

(In reply to Botond Ballo [:botond] from comment #7)
>   2) There is a coordinate systems problem, tracked in bug 1393424,
>      which causes both tooltips and the autoscroll anchor to appear 
>      in the wrong location.

The correct bug reference here is actually bug 1393494. However, that has since been marked a duplicate of bug 127909, which aims to resolve the issue by disabling tooltips, rather than fixing the underlying coordinate systems problem.

So, if we want autoscrolling to work in Print Preview again, we'll need to fix that coordinate systems issue in this bug.