169356 - Horizontal mousewheel scrolling always scrolls down

Status: RESOLVED WORKSFORME

(Core :: XUL, defect)

Description

[Nicholas Riley]

User-Agent:       Mozilla/5.0 (Macintosh; U; PPC Mac OS X; rv:1.0.1) Gecko/20020917
Build Identifier: Mozilla/5.0 (Macintosh; U; PPC Mac OS X; rv:1.0.1) Gecko/20020917

The Carbon implementation of mousewheel scrolling supports horizontal scrolling;
the Cocoa one doesn't.  If you try to scroll horizontally (in Jaguar at least,
you can do it by holding down Shift while rolling the mousewheel) Chimera always
scrolls down, whereas Mozilla behaves as if you didn't have the shift key held down.

The attached patch supports horizontal scrolling in Cocoa as well as it works in
Carbon, which is to say not at all until bug 58589 is fixed (which I'm going to
take a look at next...).  But at least it doesn't always scroll down.

Reproducible: Always

Steps to Reproduce:

Comment 1

[Nicholas Riley]

Attachment: patch

patch to clean up scroll wheel handling

Comment 2

[Josh Birnbaum]

-> Browser (where I think this belongs, based on the patch)

And confirming, since there's a patch

Comment 3

[Andrew Thompson]

Hey pink, you know all about mice. What do you make of this?

Comment 4

[Mike Pinkerton (not reading bugmail)]

look at :

-  if (hasJaguarAppKit())
-    geckoEvent.delta = -incomingDeltaY;
-  else
-    geckoEvent.delta = incomingDeltaY * -kNumLines;

and then look at :

+  PRInt32 deltaMultiplier = hasJaguarAppKit() ? -kNumLines : -1;

if i'm not mistaken, the latter has the logic backwards from the former. Is that
indended? other than that, looks good. does it not work though, because of the 3
open bugs? why does moz work if that's the case?

Comment 5

[Nicholas Riley]

You're right, they should be swapped to preserve current behavior.  I don't even
know the purpose of that code, actually; I just preserved it (well, tried to :)
because it was there and appeared to be compensating for something.

The reason this works on Mozilla is that it uses the equivalent Carbon Event
handling code, here:

http://lxr.mozilla.org/seamonkey/source/widget/src/mac/nsMacEventHandler.cpp#1444

That hard-codes a multiplier (3) regardless of OS version, and HandleScrollEvent
properly sets scrollEvent.scrollFlags based on the axis from the event.  So
vertical scrolling works, and horizontal scrolling at least behaves like
vertical scrolling until the bugs I mention are fixed.

Comment 6

[Peter Weilbacher]

Does this problem still exist with a current version of Mozilla like 1.7.3 or
1.8a5? Horizontal scrolling is implemented since 1.6 or so and should work in
principle (don't find the bug right now) and I don't think that there are Mac
specific problems. See bug 231718 how to set up the hidden prefs to activate it.

Comment 7

[Nicholas Riley]

This is fixed in Camino now (which was all this bug related to; it did not refer to the Mozilla 
implementation).  I tried 2-D scrolling in images and Web pages in the latest Camino nightly build.

Thanks to whoever fixed it.

Comment 8

[Jason Bassford]

No specific patch/bug referenced as the fix.

-> WORKSFORME.